Organic Vegetable Production - New York Cooperative Extension

Fair Use of this PDF file of

Organic Vegetable Production, NRAES-165

Proceedings from NYS Agricultural Experiment Station, January 14–16, 2003 Published by NRAES, March 2004

This PDF file is for viewing only. If a paper copy is needed, we encourage you to purchase a copy as described below. Be aware that practices, recommendations, and economic data may have changed since this book was published. Text can be copied. The book, authors, and NRAES should be acknowledged. Here is a sample acknowledgement: ----From Organic Vegetable Production, NRAES-165, published by NRAES (2004).---- No use of the PDF should diminish the marketability of the printed version. This PDF should not be used to make copies of the book for sale or distribution. If you have questions about fair use of this PDF, contact NRAES.

Purchasing the Book

You can purchase printed copies on NRAES’ secure web site, www.nraes.org, or by calling (607) 255-7654. Quantity discounts are available. NRAES PO Box 4557 Ithaca, NY 14852-4557 Phone: (607) 255-7654 Fax: (607) 254-8770 Email: [email protected] Web: www.nraes.org More information on NRAES is included at the end of this PDF.

Acknowledgments

Partial FundingThe Organic Vegetable Production workshop was partially funded by the Northeast Region Sustainable Agriculture Research and Education (SARE) program, which is administered by the Cooperative State Research Education and Extension Service and the USDA.

About the Workshop and ProceedingsThe workshop was coordinated by Abby Seaman, Area Extension Educator, New York State Integrated Pest Management Program, Cornell Cooperative Extension. The proceedings was edited by Abby Sea-man.

These meetings were intended for commercial vegetable growers who are currently growing organically or want to learn more about organic practices, as well as beginners contemplating organic vegetable production. University and farmer speakers covered the basics of soil and nutrient management, weed management, and insect and disease management.

Thanks to SpeakersThe workshop coordinator and NRAES would like to thank the speakers for their diligence in submit-ting their papers for these proceedings.

DisclaimerTo simplify information, trade names have been used in this publication. No endorsement of named products is intended, nor is criticism implied of similar products that are not mentioned.

Proceedings ProductionJeffrey S. Popow, NRAES managing editor, designed the proceedings and managed the proceedings project.

About NRAESSee the inside back cover for information about NRAES, including contact information and a list of NRAES member universities.

Natural Resource, Agriculture, and Engineering Service (NRAES)Cooperative Extension

PO Box 4557Ithaca, New York 14852-4557

Cooperative Extension NRAES–165

Proceedings from a Three-Day Series of Meetings

Jordan Hall Auditorium New York State Agricultural Experiment Station

Geneva, New York January 14–16, 2003

Organic Vegetable Production

ii

Requests to reprint parts of this book should be sent to NRAES. In your request, please state which parts of the book you would like to reprint and describe how you intend to use the reprinted material. Contact NRAES if you have any questions.

Natural Resource, Agriculture, and Engineering Service (NRAES)Cooperative Extension PO Box 4557 Ithaca, New York 14852-4557

Phone: (607) 255-7654Fax: (607) 254-8770E-mail: [email protected]

Web site: www.nraes.org

NRAES–165March 2004

© 2004 by NRAES (Natural Resource, Agriculture, and Engineering Service). All rights reserved. Inquiries invited.

ISBN-13: 978-0-935817-96-6

iii

Contents

About the Speakers ..................................................................................................................vi

Soil and Nutrient Management

Soil Life .................................................................................................................................... 3Janice Thies

Department of Crop and Soil Sciences Cornell University

Interpreting Soil Test Results and Estimating Nutrient Availability ......................................... 6John Howell

UMass Extension University of Massachusetts

Tillage Practices for Maintaining Soil Quality ....................................................................... 16Harold van Es


Compost and Cover Crops for Organic Vegetable Growers ................................................... 21Brian Caldwell

Northeast Organic Farming Association of New York

Soil and Nutrient Management Practices on Upingill Farm ................................................... 24Cliff Hatch

Upingill Farm Gill, Massachusetts

Soil and Nutrient Management Practices on Roxbury Farm .................................................. 34Jean-Paul Courtens

Roxbury Farm Kinderhook, New York

Fertility Management at Roxbury Farm ................................................................................. 45Jean-Paul Courtens


iv

Contents

Weed Management

Understanding Weed Biology ................................................................................................. 59Charles L. Mohler

Crop and Soil Sciences Cornell University

Weed Management on Organic Vegetable Farms ................................................................... 76Vern Grubinger

University of Vermont Extension

How to Get 99% Weed Control without Chemicals ............................................................... 83Brian Caldwell


Mulching for Weed Control and Organic Matter .................................................................... 87Paul Arnold

Pleasant Valley Farm Argyle, New York

Bio-Extensive Approach to Market Gardening ..................................................................... 100Anne and Eric Nordell

Beech Grove Farm Beech Grove, Pennsylvania

A Few Long Furrows on Horsedrawn Tillage ....................................................................... 105Eric and Anne Nordell


v

Contents

Insect and Disease Management

Impacts of Soil Quality on Disease and Insect Resistance in Plants .................................... 113Anusuya Rangarajan

Dept. of Horticulture Cornell University

Disease Management Strategies: Cultural Practices ............................................................. 120Helene R. Dillard

Department of Plant Pathology New York State Agricultural Experiment Station; Geneva, New York Cornell Cooperative Extension

Cultural Practices for Disease Management ......................................................................... 123Curtis Petzoldt

Integrated Pest Management Program New York State Agricultural Experiment Station; Geneva, New York

Identifying and Encouraging Beneficial Insects ................................................................... 128Michael P. Hoffmann

NYS IPM Program and Department of Entomology Cornell University

Insect Management: Managing Beneficial Habitats, Using Organic Insecticides.................................................. 136

Ruth HazzardDept. of Entomology University of Massachusetts Extension

Pest Management on Applefield Farm .................................................................................. 142Steve Mong

Applefield Farm Stow, Massachusetts

Pest Management from a Farmer’s Perspective .................................................................... 152David Marchant

River Berry Farm Fairfax, Vermont

vi

Paul Arnold and Sandy Arnold have been farming at Pleasant Valley Farm for 12 years and raise about 8 acres of organic fruits and vegetables on their 60 acres in Washington County, New York, with two children. Their living is made by selling all of their produce at 4 area farmers’ markets.

Brian Caldwell is the education director for NOFA-NY. He is also an experienced grower of organic vegetables and fruit at Hemlock Grove Farm in West Danby, New York.

Jean-Paul Courtens, the founding farmer of Roxbury Farm, was born and raised in the Netherlands, where he studied biodynamic agriculture. Roxbury Farm grows vegetables, herbs, melons, and strawberries using biodynamic practices on 148 acres in Kinderhook, New York for a CSA of 650 families in four communities.

Helene Dillard has conducted basic and applied research on the biology, ecology, and management of fungal and bacterial pathogens of vegetables at the New York State Agricultural Experiment Station in Geneva, New York since 1984. She has been the director of Cornell Cooperative Extension, a primary outreach unit of Cornell University, since 2002.

Vern Grubinger is the director of the Center for Sustainable Agriculture at the University of Vermont. He has extensive experience in many aspects of organic and sustainable veg-etable and small fruit production. He is the author of the book Sustainable Vegetable Production from Startup to Market.

Cliff Hatch has over 20 years of experience in organic production. He grows a variety of vegetables, strawberries, and grains at Upingill Farm in Gill, Massachusetts.

Ruth Hazzard is team leader for the Vegetable Program and also coordinates the Integrated Crop and Pest Manage-ment Project for vegetables. Her research has focused on insect and disease management in brassicas, sweet corn, tomato, and peppers. Currently she is involved with studies on biointensive insect management in brassicas, cucurbits, and sweet corn.

Mike Hoffmann is the director of the New York State IPM Program and a professor in the Department of Entomology in Ithaca. His research and extension program focuses on alternative insect management strategies.

John Howell recently retired as Extension Vegetable Specialist at the University of Massachusetts. His areas of special interest include vegetable production systems, nutrient and soil management, greenhouse tomato produc-tion, trickle irrigation and fertigation, and water garden construction and maintenance.

David Marchant and Jane Sorensen operate River Berry Farm alongside the LaMoille River in the Champlain Basin of Vermont. They grow approximately 40 acres of certified organic vegetables, 4 acres of IPM managed strawberries, and 15 acres of grain. The vegetables are marketed out of state through the Deep Root Organic Cooperative, and lo-cally through stores and farmers markets.

Chuck Mohler is a senior research associate in the depart-ment of Crop and Soil Sciences. Most of his work has focused on the effects of tillage, cultivation, and crop residue on the population dynamics of annual weeds. He is a co-author of the book Ecological Management of Agricultural Weeds.

Steve Mong, his wife Kirsten, and brother Ray have operated Applefield Farm for 20 years. It is a 25-acre farm with 20,000 square feet in greenhouses, which are used for bedding plant, hanging basket, annual, and perennial production. Steve has been an active cooperator in University of Massachusetts pest management trials.

Anne and Eric Nordell grow vegetables, herbs, and strawberries on 6.5 acres in Trout Run, Pennsylvania. They have developed an elegant whole farm approach to nutrient and weed management. Their produce is marketed through grocery stores, restaurants, and farmers’ markets.

Curt Petzoldt is the Assistant Director and Vegetable Coor-dinator at the New York State IPM Program. For the past ten years he has conducted multidisciplinary trials comparing the environmental and economic attributes of conventional, IPM, and organic production systems at the research farm and on growers’ farms.

Anu Rangarajan is an associate professor in the Department of Horticulture at Cornell and statewide specialist for Fresh Market Vegetable Production. Her research program focuses on specialty crop variety trials, and developing production systems that minimize chemical fertilizer and pesticide inputs and maximize crop nutritive value.

Janice Thies is an associate professor of soil biology who joined the Cornell faculty in 2000. Janice’s research program focuses on three main areas: soil microbial population genet-ics, the influence of management practices on soil microbial community structure, and the development of biofertilisers and biopesticides for use in low-input agriculture.

Harold van Es joined the Cornell faculty in 1988. His research, extension, and teaching programs address the management of soil and water resources for sustainable agricultural production and environmental protection. He is a co-author of the book Building Soils for Better Crops.

About the Speakers

Soil and Nutrient

Management

This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit www.nraes.org, or call (607) 255-7654. Page 1 of this PDF has fair use information.


Soil and Nutrient Management 3

The diverse and numerous creatures living in the soil provide a variety of benefits to crops and but also have potential detriments. The benefits include the decom-position of organic matter, nutrient cycling and release, nitrogen fixation and mycorrhizal relationships, disease suppression, and soil structure improvement. Potential detriments include immobilization of nutrients and the ability to cause plant and animal disease.

Soil food web

The complex network interactions that occur between organisms in the soil is sometimes described as the soil food web. Plants are the foundation of the soil food web, capturing energy from the sun through photosynthesis and providing the organic matter that other organisms work on. Decomposers such as bac-teria and fungi work on the material produced by the plants releasing nutrients in a form that is usable by plants. Small arthropods, nematodes, protozoa, and earthworms shred and consume the organic matter produced by the plants, making it more available to the bacteria and fungi, and also consume the bacteria and fungi themselves, releasing plant-available nutrients. Larger arthropods and small mammals then consume the smaller creatures releasing more nutrients.

Soil arthropods

There are four major groups of soil arthropods. Preda-tors such as ants, ground beetles, and spiders help con-trol crop pests. Another group including dung beetles, mites, and sow bugs shred organic matter. Fungal feed-ers such as springtails and turtle mites release nutrients tied up in fungal biomass. And herbivores such as mole crickets and symphylans can cause crop damage by feeding on roots. Functional roles of arthropods include shredding of organic matter which stimulates microbial activity, mixing microbes with organic matter, miner-alizing plant nutrients, increasing aggregation of soil, burrowing, which increases soil channels, preying on other arthropods, and feeding on plants.

Earthworms

Earthworms are another important group soil or-ganisms, considered by some to be soil ecosystem engineers. They move tremendous amounts of soil through their guts as they burrow. In the process, they stimulate microbial activity, mix and aggregate soil, increase soil infiltration rate and water holding capac-ity, create channels for plant roots, and bury and shred plant residues.

Soil LifeJanice Thies

Associate Professor Department of Crop and Soil Sciences

Cornell University


4 Organic Vegetable Production

Nematodes

Soil nematodes are very small (300-500 µm), ubiq-uitous and abundant in soils. They depend on water films on soil particles to swim and survive. They have a range of feeding strategies including plant parasites, bacterial and fungal feeders, predators, or omnivores. The different types of nematodes can be distinguished by their mouthparts. Plant parasitic nematodes have a characteristic stylet with a basal bulb, to penetrate roots. Bacterial feeders have a wide mouth opening to gather in bacteria. To evaluate the health of a soil, some researchers examine the ratio of different types of nematodes. Their functional roles in soils are to feed on bacteria, fungi, and protozoa and in turn release plant available-nutrients, feed on other soil organic matter, affecting soil structure and carbon utilization, or parasitize plants and animals.

Protozoa

Three types of protozoa can be found in soil: ciliated, flagellated or amoeboid. They are animal cells (which have no cell walls, just the cell membrane), and are therefore susceptible to and good indicators of the presence of environmental toxins. In animals, certain types of protozoa can cause disease. In soils, their principal functional role is as primary consumers of bacteria. In this way, they regulate bacterial popula-tions, increase the turnover of soil microbial biomass and organic matter, maintain plant available nitrogen, and decrease establishment of plant pathogens. They are also food for nematodes and fungi.

Fungi

Fungi have diverse roles in soil. They produce diges-tive enzymes and function as primary decomposers. They can be saprophytes, predators of nematodes, parasites of other fungi or plant pathogens. The pro-duction of hyphae by saprophytic fungi can be exten-sive, and forming a dense web in soil, and helping to improve soil aggregation. Fungi are the organisms with greatest biomass in soil. Symbiotic fungi such as mycorrhizae form associations with plant roots that enhance the survival of both plant and fungi. Some

mycorrhizae, such as many ectomycorrhizae, are good saprophytes, and function independent of plants. The ectomycorrhizae associate primarily with trees. These associations consist of a sheath surrounding the root and limited intercellular penetration between cells in the root cortex. The endomycorrhizae associ-ate primarily with crop plants. In this symbiosis, the fungi penetrate the root cortex to form an intimate relationship with host cortical cells. In both symbio-ses the integrity of the plant cell membrane remains intact and is the site of nutrient exchange with the fungus. In general, mycorrhizae improve the nutrient status of the plants (especially for phosphorus), and may protect plants from exposure to salt, desiccation, toxins or pathogens. The plant provides energy to the mycorrhizae in the form of carbon compounds. The external fungal hyphae explore more soil volume than the root itself, especially for phosphorus. This element is quickly depleted within a zone of 1 mm of the root, and does not move any further in soil. For nitrogen, the depletion zone is 10 mm from the root. The hyphae extend this depletion zone for phosphorous. These fungi increase soil stabilization. Tillage, monoculture, fungicides, and long fallows can deplete mycorrhizal populations.

Bacteria

Bacteria form the base of the soil food web. They degrade a broad range of organic materials, and some produce antibiotics. Bacteria are the most numerous organisms in soil and represent the highest diversity of species in soil. Their functional roles include nu-trient cycling and immobilization and formation of humus. There are bacterial pathogens as well, which may produce allelopathic compounds that are toxic to plants. Because of the diversity of food sources used, rapid reproduction and small size, bacteria are very responsive to changing soil environments and criti-cal players in both organic matter decomposition and nutrient cycling.

Bacteria can also form symbiotic relationships with plants. The primary example of this is the Rhizobium symbiosis responsible for nitrogen fixation in the roots of legumes. Legumes lacking the symbiotic relation-ship show signs of nitrogen deficiency when grown in low nitrogen soils, while nearby plants inoculated with the appropriate Rhizobium species do not.



The rhizosphere (root surface) is a “hotbed” of activ-ity for bacteria, actinomycetes, and fungi. Plant roots exude or secrete carbohydrates that serve as food sources for a number of beneficial and pathogenic organisms. Roots that are colonized by beneficial or-ganisms are less likely to be attacked by pathogens due to competition for nutrients, production of antibiotics, and/or parasitism of the pathogens by the beneficial organisms.

A strong food web is needed for optimal nutrient cycling and release. Research has shown that plants

Figure 1The soil food web(Source:SoilBiologyPrimer.2000.SoilConservationSociety,USDANaturalResourcesConservationService)

growing in sterilized soil produce less biomass than plants growing in soil where bacteria are present, which in turn produce less biomass than plants growing in soil where bacteria, fungi and higher order consumers are present. Regular additions of organic matter from diverse sources and avoidance of tillage practices and chemical applications that are detrimental to soil organisms will help maintain a diverse and strong soil food web on your farm.



Soil quality is of major importance to crop health and productivity. Soil management practices should strive to protect soil from erosion, maintain or increase or-ganic matter, provide an environment which promotes a diverse microbial population and create and maintain good soil tilth. A nutrient management program should: 1) supply sufficient nutrients to achieve the optimum yield that is realistic for the site; 2) avoid excess ap-plication of nutrients which can degrade water quality or which create imbalances causing lower yield and/or quality; and; 3) maintain desired soil pH, to ensure that all nutrients are readily available to the crop.

Physical properties of soil

Soil texture

Soils are composed of solid particles with spaces be-tween them. The soil particles consist of tiny bits of minerals and organic matter The areas between them are called pore space and are filled with air and water. An agricultural soil should consist of about one-half soil particles and one-half pore space by volume. Ideally, organic matter will account for 5 to 8% of the weight of soil particles. Moisture content varies considerably with factors such as soil drainage and the amount and frequency of rain or irrigation. For most agricultural crops, conditions are best when the

pore space is filled about equally with water and air.

Mineral soil particles are grouped according to size. Beginning with the smallest, they are classified as clays, silts, sands and gravel. Soils consist of mixtures of various size particles. Texture is the proportional amount of each of these groups. Note that the word loam does not refer to a specific group of particles, but is used to describe mixtures of sand, silt and clay. Soil texture is determined solely by the sizes of the mineral particles and has nothing to do with organic matter Weathering can change the size of these par-ticles, but only over thousands or millions of years. For all practical purposes, the texture of the soil does not change.

Soil texture has a major effect on the physical and chemical characteristics of soil. Sandy soils have rather large particles and large pore spaces (macropores). Clay soils have very tiny particles with very small pore spaces (micropores), but because there are many times more pore spaces, clay soils have greater total pore space than sandy soils. Water adheres to soil particles. The force of this can pull water through a soil, even against gravity. This is called capillary action, and acts in the same way water is lifted in a straw or narrow tube. In this case, water is lifted farther in a narrow tube than in a wide one. Capillary action is greater in micro pores than in macro pores. However, if a soil is compacted, all water movement including capillary

Interpreting Soil Test Results and Estimating Nutrient Availability

John Howell Extension Vegetable Specialist (retired)

UMass Extension University of Massachusetts



movement is limited. Clay soils absorb and retain more water than sandy soils, but are typically poorly drained and not well aerated. Sands are well drained as a rule, but retain little water. Loams combine some of the moisture retention characteristics of the clays with the aeration of the sands and are widely considered the best agricultural soils. Sandy soils are coarse-textured and are often referred to as “light” because they are easy to work. Clay soils are fine-textured and their particles will bond tightly together when they dry out after being wet. These soils can become very hard and difficult to work and are often called “heavy.” The terms “heavy” and “light” do not refer to weight; sands actually weigh more per unit volume than clays.

Soil structure

Structure is another term used to describe physical attributes of soils. While texture refers to the sizes of mineral particles, structure is the overall arrange-ment or aggregation of soil particles. Terms such as loose, hard-packed, granular and cloddy are among those used to describe structure. Soil structure can be modified by activities such as tillage, moisture level, freezing and thawing, root growth, earthworms and other soil inhabiting animals, and driving or walking on the surface.

Very sandy soils nearly always have a loose structure and don’t become hard-packed or cloddy. Fine-textured soils can become hard-packed. This condition inter-feres with root growth, inhibits movement of water into (infiltration) and through (percolation) the soil. The micro pores in fine textured soils can easily be filled with too much water to the exclusion of air, limiting the exchange of oxygen and carbon dioxide. The mac-ropores of coarse-textured soils facilitate infiltration and percolation of water and the exchange of gases, but they retain little water for crop use. By loosening and aggregating a fine textured soil, we can improve water infiltration, percolation, and gas exchange, and still maintain the ability to retain water for plant growth. An aggregated soil consists of granules that resemble crumbs. A granule consists of many clay or silt particles clumped together. A well granulated soil has micropores within the granules and macropores between them and is both moisture retentive and well aerated.

Natural activities such as freezing and thawing and the movement of roots contribute to granulation of

soils. Tillage at proper levels of soil moisture causes granulation. Excessive tillage in an effort to prepare a fine seed bed, especially when soils are dry, destroys soil aggregates. It is very easy to overwork a soil with a rototiller. Pounding from rain or irrigation water droplets can also destroy soil aggregates. Soils should be managed to create and maintain soil aggregates as much as possible. Mulches are an excellent way to protect aggregates from splashing water.

Biological activities are important to the granulation process. Earthworms pass soil through their digestive systems, adding viscous juices which bind particles together. Snails and other organisms leave a trail of slime behind them which acts as a glue. Organic matter is an important factor in the formation of soil aggregates and it adds greatly to their stability. Soil organic matter, particularly if it is well decomposed (humus) is a binding agent which holds clay particles together. It is believed that this is due to chemical unions between humus and clay particles. The end result is that soil organic matter plays a major role in granulation. By increasing the stability of soil ag-gregates, the soil becomes easier to work and doesn’t compact as easily.

Organic matter not only improves the structure of fine-textured soils, but it is equally beneficial for coarse textured soils. Coarse soils have a high pro-portion of macropores, facilitating gas exchange and water movement. However, due to a low proportion of micropores, these soils are not moisture retentive. This makes frequent irrigation a necessity during dry periods. Organic matter substantially increases the proportion of micropores, greatly improving the water holding capacity of a coarse-textured soil. It is estimated that for each per cent of soil organic matter, moisture holding capacity is increased by as much as 16,000 gallons per acre in the root zone.

Chemical properties of soil

Information about a soil’s chemical properties can be provided by a soil test. The soil test report indicates the levels of the nutrient elements that are available for crop nutrition. It also provides information about soil pH, buffer pH, cation exchange capacity, base saturation and organic matter. If this sounds a bit in-timidating, the following discussion should be helpful.



Essential elements

There are thirteen mineral elements known to be essen-tial for plant growth. All of these nutrients are absorbed from the soil. Six of these are called major or macro elements because the plant uses them in comparatively large amounts. They are nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S). Sometimes Ca, Mg and S are referred to as secondary elements because they are used in somewhat smaller amounts than N, P and K. The other seven are called minor, micro or trace elements. These are ev-ery bit as important as major elements, but are used in very small amounts. These elements include iron (Fe), Manganese (Mn), zinc (Zn), boron (B), copper (Cu), molybdenum (Mo) and chlorine (Cl). Nickel (Ni) is accepted by many scientists as the 14th nutrient element derived from soils. The level of crop production can be no greater than that allowed by the most limiting of the essential elements.

In addition to mineral elements, carbon (C), hydrogen (H) and oxygen (O) are essential elements. Plants take these elements from air and water. Although these ele-ments are not applied as fertilizer materials, our soil management practices affect their availability.

Soil pH

One of the most important aspects of nutrient man-agement is maintaining proper soil pH. Soil pH is a measure of soil acidity. A pH of 7.0 is neutral. If the pH is below 7.0, the soil is acid, but if it is above this level it is alkaline. Most soils in the Northeast are naturally acid and need to be limed periodically to neutralize excess acidity. Soil pH is important because it affects the availability of nutrient elements for plant uptake. Availability of macro-elements and molybdenum (Mo) is restricted in acid soils. Under alkaline conditions, with the exception of Mo, the availability of microele-ments is reduced. Under acid conditions, Ca and Mg are frequently low and there may be toxic levels of iron, aluminum and manganese. Most crops, do best when the soil pH is in the range of 6.0 to 6.8. At this pH, the availability of macro and micro elements is maximized, and accumulation of toxic elements is minimized. Although most soils in the Northeast are able to supply sufficient amounts of microelements, growers may find deficiencies in some of the sandy soils. A soil pH of 6.0 to 6.2 is more appropriate for

these soils. Clearly, you cannot expect to achieve the benefits of other amendments when pH is suboptimum.

Cation exchange capacity

“Ions” are atoms or groups of atoms (molecules) which have an electrical charge. “Anions” have a negative (-) charge and “cations” have a positive (+) charge. Plants take up nutrients from the soil either as cations or anions. Many of the nutrient elements are cations (pronounced cat-eye-ons). These include Ca++, Mg++, K+, Fe+++, Mn++, Zn++, Cu++ and ammo-nium (NH

4+) which is a form of N. Other cations of

importance are H+ and Al+++ (aluminum). Anions of importance include nitrate (NO3-), a highly leachable form of nitrogen.

Cations are attracted to negatively charged surfaces of small clay and organic (humus) particles called col-loids. This attraction is called adsorption. Generally, cations are held tightly enough on adsorption sites to restrict their loss through leaching. These cations can move from the adsorption sites on colloids into the soil water solution and vise versa. In the soil solution, they are available for root uptake, but are also subject to leaching (see Figure 3). Cation exchange capacity (CEC) is a measure of the number of adsorption sites in a soil and is an important indicator of the soil’s ability to retain and supply cations for plant use. CEC is reported as milli-equivalents per 100 grams of soil (meq/100 g). The CEC of agricultural soils ranges from below 5 in sandy soils with little organic mat-ter to over 20 in certain clay soils and those high in organic matter. A soil with a low CEC has little ability to store nutrients and is susceptible to cation nutrient loss through leaching.

Cation exchange capacity is related to soil texture. Of the mineral particles, clay is the only group which makes a significant contribution to CEC. However, there are several types of clays, and they vary con-siderably in their CEC. Crops are grown on a wide range of soil types, including many that are sandy and low in clay. In many areas of the Northeast, the types of clay present have a low CEC. In much of the region’s soils, organic matter is the primary contribu-tor to CEC. This fact is true even of soils with low organic matter. Not only does organic matter improve the physical properties of soil, it also plays a vital role in soil chemistry by increasing CEC.



Base saturation

The cations Ca++, Mg++, K+ and H+ normally account for nearly all cations adsorbed on soil particles, although trace elements that are cations are also present in minute quantities. Ca++, Mg++, and K+ are base cations that raise soil pH and H+ and Al+++ are acidic cations that lower soil pH. If all of the adsorbed cations are bases and none are acidic, there would be a 100% base saturation, and the soil pH would be about 7 (neutral) or above. In acid soils there are acid cations pres-ent and the percent base saturation is less than 100. Besides having sufficient quantities of Ca, Mg and K, they should be in balance with each other because an excess of one of these can suppress the uptake of another. As a general rule a Ca:Mg:K ratio of about 20:4:1 is desirable. When expressed as percent base saturation, desired levels are: Ca 65-80%; Mg 5-15%; and K 2-5%.

Soil organic matter

As already noted, soil organic matter (SOM) improves moisture holding capacity of sandy soils, aeration of clay soils and helps overall structure of any soil. Soil organic matter is the chief contributor to cation exchange capacity in many soils and is an important factor in all soils. The break down or decomposition of SOM releases nutrients which can be used by plants. Organic matter is also food for organisms that are es-sential for a healthy soil environment.

By definition, organic matter contains carbon. Carbon is a source of energy for microorganisms (microbes) in the soil. These are microscopic plants and animals such as bacteria and fungi. Some of these are patho-gens which cause plant disease, but in a healthy, well managed soil the vast majority are beneficial. Organic matter provides food for a diverse popula-tion of microbes in the soil and this helps prevent any one type of organism, such as a plant pathogen, from dominating.

Soil organic matter is continuously being produced and broken down by living plants and animals. Dr. Fred Magdoff of the University of Vermont coined an appropriate phrase: There are three kinds of SOM; the living, the dead and the very dead. The living fraction of the SOM is made up of living plants and animals, including microbes, that are found in the soil. When they die, stalks, leaves and other plant parts retain

recognizable characteristics for a while. This is the dead fraction of the SOM. It is also called the active fraction because it supports microbial activity. Sooner or later the dead organic matter decays due to microbial activity and cannot be recognized for what it was and eventually becomes humus. This is very dead organic matter. It is also called inactive organic matter because it will no longer support microbial activity. In addition, animals eat plants or other animals and pass some of their food through their bodies as manure which is rich in nutrients and organic matter.

Organic matter consists of numerous compounds which vary greatly in their ease of decomposition. Sugars, starches and proteins are rapidly decomposed by microbes while lignin, fats and waxes are resistant to this process. Fresh organic residues consist mostly of easily decomposed compounds which break down rapidly under favorable conditions. The result is a rapid reduction of the volume of SOM. The resistant materi-als remain and form the dark colored material called humus. Humus continues to decompose, but at a very slow rate. Carbon dating has shown some humus to be thousands of years old. Humus forms the colloids which contribute to increased cation exchange capacity and good soil structure.

Soil organic matter is broken down by microbes as they consume it for food. Any factor that affects soil microbial activity also affects SOM break down. In the microbe, respiration combines most of the carbon from SOM with oxygen to form carbon dioxide gas. For this process to continue, there must be an exchange of oxygen and carbon dioxide between the atmosphere and the soil pore spaces. Gas exchange can be restricted if the soil is compacted or saturated with excess water. This slows the rate of SOM decomposition. While excess water inhibits decomposition, a certain amount is necessary to support microbes. Therefore, condi-tions of moisture stress can be expected to slow the decomposition of SOM.

Soil microbes are also influenced by soil pH and tem-perature. This is especially true of bacteria. Under acid conditions, bacterial activity in breaking down organic matter is greatly reduced. Soil fungi responsible for break down of SOM are generally less affected by low pH. In most cases, however, bacteria are respon-sible for most of the decomposition of SOM, and as a rule this process is markedly slowed if soil pH level drops below 6.0. The optimum soil temperatures for



bacterial activity are in the 70 to 100° F range, but activity occurs as low as 40° F, although at greatly reduced rates.

A moist, warm, well aerated soil with a pH between six and seven provides ideal conditions for decompo-sition of SOM. These are the conditions that promote optimum growth of most crops. Productive farming practices can be quite destructive to SOM! This may seem frustrating if you are trying to build SOM, but decomposition is a beneficial process. It provides energy for a diverse group of soil microbes, releases nutrients for plant growth and produces humus. The challenge is to continuously replace what is lost and, if practical, increase SOM.

Adding to soil organic matter

Compost is an excellent source of organic matter that nearly all farmers can make. Most growers don’t have enough raw materials to satisfy their needs. Some are bringing in additional materials such as municipal yard wastes to compost on site. Others are purchasing compost from the increasing number of commercial composters. Regardless of the source, compost should be finished before use. Finished compost has no recog-nizable bits of matter and will not heat up after turning. Compost should be tested for nutrient content. Most soil testing laboratories can test compost. Finished compost should have a low ammonium content, high nitrate level and a pH near neutral. Repeated use of a compost high in a particular element may cause a nu-trient imbalance and result in excess levels of certain elements. This can easily be avoided by soil testing on a regular basis (at least every three years).

Animal manure is an excellent source of nutrients and organic matter. About half of the nitrogen in fresh dairy manure and 75% of the nitrogen in poultry manure is in the form of ammonia. Ammonia is subject to loss through volatilization if not incorporated immediately after spreading. In the soil, ammonia is converted to nitrate and is available for plant use. However, since nitrate is subject to leaching, large applications should generally be avoided. There are times when readily available nitrogen is needed, but fresh manure should be applied with caution. Many people prefer to com-post manure before field application. This stabilizes the nitrogen. Manure can be mixed with other materials for composting. There are strict certification re-quirements for composts that contain manure and

there are required intervals between application of manure and harvest of edible crops. Check with an accredited certifying agency.

Soil testing

Sampling a field

To collect a soil sample, use a soil probe, soil auger, or garden shovel to collect samples from throughout the field. Use a “V” or “W” pattern to ensure that the sample is representative of the field. Areas of the field that appear to be a different soil type, have been man-aged differently, or where you have observed poor growth, should be sampled separately.

Scrape away surface litter from the sites you choose, and then collect a core or slice of soil to the plow depth—usually about 6-8 inches. Collect cores from 10-15 different sites and place them in a plastic bucket. Mix these samples well, and then take about one pint of soil from this mixture to send to the lab. It is best to air dry this sample before you send it to the lab.

The report you receive from the lab should indicate soil nutrient levels of most of the macronutrients and some of the micronutrients, pH, and organic matter. Some labs also include cation exchange capacity, buffer pH or exchangeable acidity, and/or base saturation.

Adjusting pH

Lime is used to correct the pH of acid soils. The amount of lime needed depends on several factors, including current and desired pH, soil texture and soil organic matter. Soil testing laboratories measure soil pH, which is actually a measure of the concentration of H+ in the soil solution. This is called active acidity. There is also H+ adsorbed onto soil colloids. This is called reserve (or exchange) acidity and this is related to cation exchange capacity (CEC). When lime is added to the soil, reac-tions occur which result in H+ being replaced by Ca++ and/or Mg++. At the same pH, a soil with a high reserve acidity (loams, clays, high humus) may require 3 to 4 times as much lime as one with a low reserve acidity (sands, gravels). The soil testing laboratory uses a procedure to determine the lime requirement of a soil based on its reserve acidity. A buffer pH test is the most common method used to determine lime requirement,



but some laboratories use other procedures.

The speed with which lime reacts in the soil is depen-dent on particle size and distribution in the soil. To determine fineness, lime particles are passed through sieves of various mesh sizes. A 10 mesh sieve has 10 openings per linear inch, or 100 openings per square inch (10 X 10) and a 100 mesh sieve has 10,000 openings per square inch (100 X 100). Lime particles that pass through a 100 mesh sieve are fine and react rapidly—within a few weeks. Coarser material in the 20 to 30 mesh range will react over a longer period such as one to two years or more. Agricultural ground limestone contains both coarse and fine particles. About half of a typical ground limestone consists of particles fine enough to react within a few weeks or months, but to be certain you should obtain a physical analysis from your supplier.

Super fine or pulverized lime is sometimes used for a quick fix because all of the particles are fine enough to react rapidly. Hydrated lime, “quick lime” are fast acting, but are not approved for use in organic systems because they are highly caustic.

For the most rapid results, lime should be thoroughly mixed with the soil. Plowing turns lime under to the plow depth, but does not mix it with the soil. Harrow-ing can do a good job of mixing, but generally only incorporates lime to a depth of two to three inches. A split application can be use in which half the lime is plowed under, and the remainder is applied after plow-ing and harrowed in. A rototiller is effective for soil incorporation. Weather permitting, it is best to apply lime when the soil is somewhat dry. If lime is spread on damp soils, it tends to cake and will not mix as well with soil particles. If the soil pH is already at a reasonable level and rapid results are not needed, lime may be recommended to maintain current levels. In this case plowing or simple harrowing are sufficient for incorporation.

Besides raising soil pH, lime is the most economical source of Ca and Mg for crop nutrition. Select liming materials based on Ca and Mg content with the aim of keeping these nutrients in balance. If the Mg level is low, a lime high in Mg (dolomite) should be used. If Mg is high and Ca is low, a lime high in calcium (calcite) is preferable. “High Mag” lime contains about 5% Mg and 35% Ca by weight. Use this if both Ca and Mg are needed. Continual use of one type of lime over several

years can lead to an imbalance between Ca and Mg. Because dolomitic lime is the most readily available liming material in some areas, many growers have used it continuously. As a result, many fields are low in Ca and very high in Mg. Choose liming materials to achieve and maintain appropriate base saturation levels. Shop around for and insist on the appropriate material, even if you must pay for increased hauling costs. Gypsum may be used to increase Ca if calcite is not available, but it does not affect soil pH and is expensive.

The neutralizing power of lime is determined by its calcium carbonate equivalence (CCE), also referred to as Effective Neutralizing Value (ENV). Recommen-dations are based on an assumption that lime is pure calcium carbonate which has a CCE (ENV) of 100%. If lime has a lower CCE (ENV), more than the recom-mended amount is needed, but if it is higher, as with some dolomitic limes, less is required. To determine the amount of lime to apply, divide the recommended amount by the per cent calcium carbonate equivalence of the lime to be used and multiply by 100. For ex-ample, if the lime recommendation is 2 tons per acre and the lime has a CCE of 72%, apply 2.7 tons per acre according to the following calculation:

recommended amount X 100% = amount CCE needed

OR

2 tons/A X 100% = 2.7 tons/A 72%

Wood ashes can also be used to raise soil pH. The calcium carbonate equivalence of wood ashes varies considerably, typically ranging from 30 to 50%. They are chemically similar to quick lime and supply K as well as Ca and Mg. CAUTION: Do not over-apply wood ashes. Wood ashes spread in a concentrated area cause the soil pH to become extremely high, inhibiting plant growth.

On some soils, it may be necessary to lower the pH. Elemental sulfur can be used for this purpose. Like limestone, particle size and thoroughness of mixing affect the speed of reaction. It typically requires six months to a year to lower pH to the desirable range. The ability of sulfur to lower pH varies among soils. Sulfur must be oxidized to be acidifying. This process



is carried out by certain bacteria. If they are not pres-ent in the soil, this reaction, and hence, acidification will not occur.

Nutrient management

Macronutrients

Nitrogen

Nitrogen is often the most limiting nutrient. Deficiency symptoms include yellow plants and stunted, weak growth. The majority of crops absorb most of their nitrogen in the nitrate (NO

3-) form, but they can ab-

sorb some ammonium (NH4

+). Unfortunately, nitrate-nitrogen is very soluble and is easily leached. In most soils, a considerable amount of nitrogen is tied up in organic matter (crop residues, soil organic matter, mi-crobes, etc.) not immediately available to plants. This nitrogen must be released by microbes as they consume organic matter. This process is called mineralization These microbes are most active when the soil is warm, moisture and aeration are optimum and pH is 6.0 or above. Cool conditions, dry or waterlogged soils, low pH or compaction will slow the conversion of nitrogen to available forms. Under favorable conditions, we can usually expect from 20 to 40 lbs. of nitrogen per acre for each per cent soil organic matter.

Nitrogen uptake varies from as little as 50 lb./A for snap beans to 200 lb/A or more for field corn. Soil organic matter can provide some and in some cases all of a crop’s need for nitrogen. The rest can be provided by adding an organic fertilizer. Manure can supply a substantial amount of readily available nitrogen. For safety reasons and to meet certification require-ments, a minimum time interval is required between application of non-composted manure and harvest of edible crops.

Phosphorus

Phosphorus, like nitrogen, can be found in organic and inorganic portions of the soil. P deficiency appears as a purpling of leaf tissue. P is found in three forms in soil; two of which are unavailable to plants. The unavail-able forms include P in organic matter and phosphorus fixed or bound to iron and aluminum at low pH, and

calcium and magnesium at high pH. Added fertilizer phosphorus is fixed with other elements and is only very slowly made available. Since this is a chemical reaction, it is faster in warmer soils than in cooler soils. Banding P with a material such as bone meal, rather than broadcasting, is a more efficient way to apply this nutrient if needed. Manure is a good source of easily available P.

Potassium

Potassium is the third of the “primary elements.” Crops deficient in K can suffer considerable loss in yield or quality without showing obvious symptoms. This is often called hidden hunger. In severe cases, leaf edges may be scorched. Plants absorb potassium in the ion form K+. Potassium can be leached from sandy or gravelly soils of low CEC and be fixed and unavail-able in some clays.

Calcium

Calcium is absorbed by roots in the ion form Ca++. Deficiency symptoms include young leaves that are stunted, distorted and spotted and necrotic at the leaf edge. Blossom-end rot is seen in tomatoes and other fruiting crops. Although calcium may be present in high levels in the soil, dry conditions will limit its uptake by plants and cause deficiency symptoms. High levels of sodium, K, Mg, and ammonium may also cause deficiency by interfering with Ca uptake.

Magnesium

Magnesium is absorbed in the Mg++ form. Deficiencies appear on older leaves as regions between leaf veins which become yellow and sometimes a reddish color progressing to brown. Deficiency is most common on acid, highly leached soils or those that are high in potassium or calcium.

Sulfur

Sulfur is cycled through soil in a very complex fashion, similar to nitrogen. In the northeast, significant quanti-ties of sulfur are supplied by air pollution. Deficiency symptoms, while rare, first appear as a yellowing of the younger leaves (as compared to older leaves with nitrogen). Sulfur deficiency is more likely in acid, sandy soils, low in organic matter.



Micronutrients

Micronutrients are not often deficient. Deficiencies are more likely in soils with high pH or sandy soils with low organic matter. Some of the more common elemental deficiencies are mentioned below.

Irondeficiency

Iron deficiency appears as a white or yellow area between the veins of youngest leaves. It is most com-monly seen on soils with higher pH and can often be worsened by liming. Excess P can tie up some iron as well.

Manganesedeficiency

Manganese deficiency can result in yellowing of the interveinal areas of young leaves (as compared to older leaves for magnesium). It is most common on soils with pH above 6.8.

Zincdeficiency

Zinc deficiency often shows as small, abnormally shaped leaves and stunted plants. As with iron, excess P can tie up zinc.

Borondeficiency

Boron deficiency may result in browned, distorted, brittle plants. Fruit may be affected by cracks, necrotic spots, and internal breakdown. Stems of cruciferous crops may be hollow. It may occur on alkaline, highly leached, or low organic matter soils. Caution: some crops are sensitive to high levels of boron; don’t ap-ply more than two lb per acre. Solubor or boraxo are approved sources for organic agriculture.

Determining what nutrients to add and how much

The only way to know the nutrient needs of a soil is by testing. Guess work is dangerous. There are numerous examples of fields with serious nutrient imbalances and excesses where they were not monitored by soil testing. Most soil test reports indicate nutrient levels in terms of parts per million (ppm) or pounds per acre

(lb/A). This is not usually very helpful to a grower, but the report also has a rating of low, medium, high (optimum) and very high (excessive). These ratings are useful in determining the need for nutrient applications.

Generally, it is best to have nutrient levels in the high/optimum range. This means that for most crops, there is an adequate supply of nutrients. If a nutri-ent is in the medium range, it is likely to limit crop production, but not severely. In such cases, crops can be expected to respond to application of the nutrient some extent. If a nutrient level is in the low range it is likely that it will limit production to a greater extent. In this situation, increasing the level of the nutrient element will probably benefit the crop significantly. Conversely, if a nutrient is in the very high/excessive range, it may interfere with the availability of certain other nutrients which are otherwise in adequate sup-ply. Excess levels of nitrogen and phosphorous also create potential hazards to water quality, and in the case of nitrate-nitrogen in drinking water, can have serious health effects.

One of the goals of a soil management program should be to maintain nutrient levels in the high/ optimum range. If a nutrient is in or is approaching the very high/excessive range, it should not applied until the level drops back into the high/optimum range. This is challenging for organic growers, because many amendments such as compost contain a number of different nutrients. If a material is used, it may supply some needed nutrients, but may also increase the level of nutrients already in excess. Also, many materials are slow to release nutrients and may continue to do so after levels are in the very high/excess range. The best way to avoid excess nutrient levels is to test the soil regularly and be aware that many materials will continue to increase soil nutrient levels for some period of years after application.

Pre-sidedress soil nitrate test

The pre-sidedress soil nitrate test (PSNT) was origi-nally developed to improve nitrogen management in field corn on farms with a significant amount of ma-nure usage. It has been adapted for use in vegetable crops to predict the need for applying supplemental nitrogen during the growing season. Regular soil tests



performed in the fall, winter or spring do not provide an accurate indication of nitrogen levels in the soil during the growing season. The PSNT can also be a useful tool for organic growers to monitor nitrogen levels during the summer, when this nutrient is normally at its high-est levels. This allows the grower to adjust applications of nitrogen containing amendments, such as compost to avoid excesses of deficiencies. A nitrate-nitrogen level of 30 ppm measured in early summer is believed to be adequate for most crops. Levels above 50 ppm are considered excessive.

To sample for the PSNT, collect 15 to 20 subsamples from the top 12 inches of soil about one week before the pumpkin vines begin to run. Mix the subsamples and retain about one cup full for the test. Soil samples should be spread on a nonporous surface to air dry soon after sampling. Follow the general directions for collecting soil samples described on page 10 in this chapter. When the soil is dry, send your sample to a soil testing lab for a nitrate-nitrogen test.

Organic fertilizers

Nutrients need to be added to fields to replace those which have been removed by harvesting. If a soil is low in a nutrient(s), extra effort is needed to achieve suitable levels for optimum production. Organic fertilizers include animal manures, compost, green manures, and other natural materials. Many of these are slow to become available to plants, but contribute to soil fertility in the long run. Some are available more rapidly and are useful to correct a problem or to supply certain nutrients while fertility is built up with other amendments. Some common organic fertilizers are listed in Table 1 along with typical nutrient values and relative availability. The list of allowed inputs sometimes changes, so it is important to consult with an accredited organic certifying agency to determine what fertilizer materials are currently allowed.

Organic fertilizers often improve soil organic matter and generally have a positive impact on soil tilth. They are easy on earthworms and microbial popula-tions. However it is possible to achieve excess levels of some nutrients if some amendments are applied at high rates over a period of time. This can be avoided by monitoring levels by regular soil testing.

References

Brady, Nyle C. 1974. The Nature and Properties of Soils. 8th edition. MacMillan Publishing Co. New York.

Garrison, Steven, ed. 1999. Commercial Vegetable Production Recommendations for Delaware, Mary-land, New Jersey, Pennsylvania and Virginia. Coopera-tive Extension Systems of Delaware, Maryland, New Jersey, Pennsylvania and Virginia

Heckman, Joseph. 2002. Personal communication.

Howell, John C., ed. 2002. 2002-2003 New England Vegetable Management Guide. Cooperative Extension Systems of New England.

Howell, John C. 1998. Soil Basics I, II and III. Univer-sity of Massachusetts Extension Fact Sheets: VegSF 1, 2 and 3-98

Magdoff, Fred. 1992. Building Soils for Better Crops: Organic Matter Management. University of Nebraska Press. Lincoln.

Sachs, Paul D. 1993. Edaphos: Dynamics of a Natural Soil System. Edaphic Press. Newbury, Vt.

Pohl, Susan, ed. 1994. Vegetable Production Hand-book. Cornell Cooperative Extension.



Table 1Organic Fertilizers. Check with certifying agent on current status.

Material N (%) P2O

5 (%) K

2O (%) Relative Availability

Alfalfa pellets 3 0.5 3 slowDried blood 13 2 0.5 med/rapidBone meal (raw) 2-6 15-27 0 slow/medBone meal (steamed) .5-4 18-34 0 slow/medCocoa shells 1-2 1 2-3 slow

Compost (unfortified) 1-3 .5-1 1-2 slowCompost (fortified blends) 3-5 3-4 3-5 slow/medCottonseed meal 6 2 2 slow/medFish emulsion 4-5 1-2 1-2 rapidBat guano 6 9 2 med

Manure (fresh) dairy .5 .2 .5 med/rapid horse .6 .2 .5 med sheep 1 .3 1 med/rapid poultry 1-3 1-2 .5-2 med/rapidPumace (fresh apple) 6-7 1-2 .2 slow

Soybean meal 6-7 1-2 2 slow/medTankage (dry) 6-7 10-14 0 medWood ashes 0 1-2 3-7 rapidColloidal phosphate 0 18-25 0 slow; about 3% availableGranite dust 0 0 3-5 very slow

Greensand 0 0 4-9 very slowRock phosphate 0 20-32 0 slow; about 2% availableSodium (Chilian) nitrate 16 0 0 rapidSul-Po-Mag 0 0 22 rapid; also contains Mg and SEpsom salts 0 0 0 10% Mg-rapid

Nutrient content varies with origin and handling; availability depends on fineness of grind.



Healthy soil is the foundation of sustainable crop production. It is the result of a combination of factors. While this presentation will focus mostly on how till-age affects soil health I first want to briefly go over the “bigger picture” of soil health.

A key concept for managing soil health is recognizing the interaction between the biological, chemical, and physical aspects of soil. Biologically healthy soil has low pest populations, or the ability to suppress pests, and is fully functional with respect to nutrient cycling and producing plant growth promoting compounds. From the chemical perspective, healthy soil has ad-equate levels of available nutrients, but not so high that there will be a lot of leaching; an optimal pH for the planned crop rotation; and low levels of toxic or disruptive substances such as heavy metals, aluminum, or salts. The physical characteristics of healthy soil include good tilth, water infiltration, aeration, and water retention.

The biological, chemical and physical properties mu-tually influence each other, and if we ignore one, the other will be affected. For example, aggregation of soil particles is influenced by the types of cations (e.g. Ca, Mg, K) and amount of organic matter present in the soil. The types of organisms present can be influenced by compaction and availability of food sources, and soil drainage influences the amount of nitrogen avail-able to plants because saturated soil can lose nitrogen

through denitrification, and well drained soil can lose nitrogen through leaching. In the past decades, agri-culture has too much focused on the chemical aspects of soils and insufficient attention has been given to the physical and biological (especially) functions.

The key management approaches that can positively influence soil health are organic matter additions, reduced tillage, and compaction prevention. Adding organic matter to the soil increases biological activity and diversity, which in turn releases plant-available nutrients and holds them in the soil, increases soil ag-gregation, pore structure, and tilth, produces humus and other plant growth promoting substances, and reduces soilborne diseases and parasitic nematodes (Fig. 1). At least one long term cropping experiment has shown a yield increases related to increasing or-ganic matter levels, especially in dry years when higher organic matter levels can improve water retention.

Now we’ll move on to tillage. One question we can ask ourselves is why we till in the first place. The plow, which was invented in the England in the mid-1700s, revolutionized agriculture. It provided unprecedented control of weeds, allowed for a more stable food supply, and was a critical tool in the development of virgin lands in North America. Plowing the soil incor-porates residue from the previous crop, weeds, and amendments. It’s the first step in seedbed preparation, increases the conversion of organic matter to plant-

Tillage Practices for Maintaining Soil QualityHarold van Es




available nutrients, and reduces compaction, at least temporarily. So, the first experience with the plow was very positive, mainly because the destructive qualities didn’t manifest themselves until after several decades.

In that respect, it is interesting to study the contribu-tions of the eighteenth-century English agriculturalist Jethro Tull. Tull made an everlasting contribution to the worlds by inventing the seed drill, as he recognized that good seed placement improved germination and plant population over the conventional broadcast seeding (of small grains). Now, we recognize that the mechanical seeder is an essential agricultural tool, especially for conservation farming because no-till planters allow us to place seeds with very minimal tillage. Tull, however, also appears to have done an unintentional disservice to the land. He believed that plant roots absorbed nutrients as tiny soil particles (rather than as ions as was established in the following century). He therefore tilled his soils over and again to pulverize it. Sure enough, he was able to feed his crops for many years without the use of manure or other forms of fertilizer. But what was he doing? He

oxidized the soil organic matter and released nutrients for his crops. In time, however, he mined the soil of its nutrients and food source for soil organisms. In the long run this is not sustainable, and we have seen similar problems with modern farming methods. One interesting lesson learned from Tull’s work is that short-term research does not always provide the right picture.

There are also other negative aspects of plowing. It uses a large amount of energy, and repeated plowing destroys soil aggregates, which increases compaction and the potential for crusting, resulting in low water infiltration, increased erosion, and the development of a zone of low microbial activity near the soil surface. Intensive soil tillage exposes the soil to the elements and causes temperature and heat extremes near the surface, creating an environment that is uninhabit-able for soil organisms. In that respect, we need to start changing our somewhat romantic image of clean tillage, which we often associate with goodness and tradition. What could be better than a beautiful, aro-matic freshly-plowed field? In fact, we are actually

Addorganicmatter

Increased biological activity (& diversity)

Decomposition

Nutrientsreleased

Aggregationincreased

Pore structureimproved

Humus and othergrowth

promotingsubstances

Reducedsoil-borne diseases,parasitic nematodes

Improved tilthand water storage

HEALTHY PLANTS

Harmfulsubstancesdetoxified

Figure 1



doing something very unnatural, because soil is not naturally exposed to the elements and we are creating an ecologically unfavorable soil environment. A field covered with residues may not have the aesthetics of a plowed field, but it is a lot more ecologically compat-ible. Farm ugly, as they say.

Another factor associated with increased soil degrada-tion is driving heavy farm equipment on a field. The weight of heavy equipment is concentrated in a small area underneath the tires, and can certainly increase soil compaction, especially if the soil is wet. The level of compaction is greater and extends deeper into wet soil than into dry soil, reminding us of the importance of staying off fields when the soil is wet.

The notions of water availability and compaction are brought together in the concept of the “optimum water range.” Highly compacted soil has a smaller optimum water range than a well-structured soil (Fig. 2). During wet periods, compacted soils experience prolonged water saturation and aeration problems, because they

do not have the large pores that readily drain and allow air into it. When the soil dries, compacted soils more readily experience drought stress, which is actually caused by hard soil not allowing for root penetration. So crops growing on compacted soil are “happy” only when the moisture conditions are “average.” During prolonged dry or wet periods, however, the plants quickly become stressed and have decreased yield or quality. A well-structured soil will not show drought or aeration problems unless the conditions are very extreme.

So how do we improve soil health? First, we have to recognize that some soils have become “addicted” to tillage. Depletion of organic matter over time has resulted in soils that are so compacted that multiple passes are needed to break up clods to create a good seedbed. The relief is only temporary, however, as these soils usually settle back down and form crusts after the first good rain, inhibiting seedling emergence and root growth. What can we do to remediate such soils or prevent them from occurring in the first place?

Figure 2



Building Healthy Soils

In general, the following practices will help build soils:

1. Organic Matter Management

• Add organic matter to the soil regularly.

• Use different types of organic materials.

• Use different sources of organic materials

• Reduce organic matter losses

• Keep soil surface covered with living vegetation as much as possible

2. Improved tillage

• Minimize tillage intensity

• Optimize timing

• Maximize surface cover

3. Minimize soil compaction

• No traffic on wet soils (by far most important)

• Minimize soil loading by reducing equipment weight and spreading the load with multiple axles and large tires

• Use controlled traffic lanes, and take advantage of ridges and beds

Reducing tillage results in many changes in the soil including higher carbon (organic matter) levels, bet-ter structure, better water availability, more biological activity, and reduced erosion.

Other changes to keep in mind are that soils may also stay cool later in the spring, nutrients may become stratified (higher levels near the surface) because they are not being mixed into the soil profile, and the pH of the surface soil will change more rapidly after ap-plications of lime because the lime is not being mixed with a larger amount of soil.

There is a range of options for reduced tillage, includ-

ing no-till, strip till, ridge till, and zone till. The cooler soils associated with no-till can be a challenge in the Northeast. Strip, zone, and ridge till are adaptations of no-till that can overcome some of the cool soil problems. The narrow tilled zone warms up faster due to the removal of a small amount of residue, and is loosened and aerated, creating more favorable conditions for germination and growth. My research program has shown that no till is most successful when used with crop rotations rather than in monoculture. Also, we found that using ridges or beds, which force controlled traffic, are very attractive for our climate conditions, especially on medium and fine-textured soils. No-tillage is generally very successful on sandy and gravelly soils, which have less compaction prob-lems and are more drought sensitive.

We have learned that a good no-till seeder is a criti-cal piece of equipment, because it allows for good seed placement under a range of conditions. Many times, farmers perform intensive tillage just to create a seedbed, while fine tilth is only needed in the soil immediately surrounding the seed. With a no-till or zone-till planter, tillage options are much more flexible. If serious cover cropping is part of the management of the farm, a no-till drill is essential. There should be no tillage prior to cover crop seeding, because that mostly negates its benefits. Recent studies conducted in Michigan suggest that even when cover crops or manure are used in a rotation, soil organic matter levels don’t increase when a moldboard plow is used for till-age. Tillage practices such as no-till, zone-till, strip-till, and ridge-till do result in an increase in organic matter, even when cover crops are not used. In other words, the less the soil is disturbed, exposing organic matter to the air, the less organic matter is oxidized and lost to the atmosphere.

Mulching is another practice that can benefit soil health by providing cover for the surface of the soil and pro-viding a source of organic matter. The use of mulches enhances water availability by improving infiltration into the soil and reducing evaporation from the soil. Mulching provides weed control by shading the soil surface and inhibiting weed germination, reduces splashing of soil and disease inoculum onto leaves and fruit, and reduces infestations of certain insects (i.e. Colorado potato beetle) on plants grown in a mulch system. Also, the temperature and moisture modera-tion from a covered soil promotes biological activity.



While bringing cut mulch into a field is feasible on a small scale, a different approach is needed for us-ing mulch on a larger scale. Steve Groff, an innova-tive farmer in southern Pennsylvania has adapted a technique for planting into standing mulch that was developed by USDA researchers. Steve uses a no-till seeder or transplanter to establish a crop into the mulch from a killed rye/vetch cover crop that was planted in the fall of the previous growing season. The cover crop is killed either with herbicides or by a piece of equipment that rolls down and crimps the cover crop just as it starts to flower. You can learn more about this technique from Steve’s web site: <http://www.cedar meadowfarm.com/>.

What type of tillage makes the most sense on any par-ticular farm? It depends…on the type of operation, the

soil types, and the climate. What works for one grower in one part of the state may not work for another grower in another part of the state. Choose a system that is most efficient in terms of energy use and passes across the field, can handle organic matter additions in the forms available to you, and is appropriate for your manage-ment style and operation. Be aware that a there is often a yield reduction that lasts 2-3 years when changing to minimal tillage systems on unhealthy, degraded soils. Start small and develop a system that works for you before using it on your entire farm.

A good resource for learning more about soil health is: Building Soils for Better Crops by Fred Magdoff and Harold van Es. It’s available from the Sustainable Agriculture Network, <http://www.sare.org/>.



Applying compost and growing cover crops are ex-cellent practices for growers to use to enhance soil fertility. They improve the soil’s nutrient, physical, and biological status.

Improving soil with compost

If one starts with a depleted soil, the first thing to do is to correct the pH with lime if necessary, and then add compost to boost overall nutrient levels and biologi-cal activity. This initial boost of compost is generally put on at a high rate of 10 tons per acre or more. Uncomposted manure can be used in a similar way, observing the time to harvest restrictions required by organic certifiers.

Composts made from different feed stocks can have widely different analyses. Chicken manure has very high relative phosphorous levels, since chickens are fed large amounts of grain, which is relatively high in P. Therefore, compost made with large amounts of chicken manure is also relatively high in P. Poultry manure composts generally have higher nitrogen-phosphorous-potassium (N-P-K) percentages than composts made from other feedstocks, some as high as 5-5-5. Conversely, composts made mostly with plant matter may have an analysis below 1-1-1. If you pur-chase compost, get an analysis from your supplier so

you know what levels of nutrients you are applying to your fields. Otherwise, have a sample of your compost or manure analyzed at a lab.

A few years (perhaps 3-5) of heavy, but diminishing compost applications will bring soil nutrient levels up into the “high” range, even under heavy cropping. Crops remove far fewer nutrients than will have been applied. A ton of compost may contain 10 to 60 or more pounds of nitrogen, of which around half will be in available form. It may also carry similar amounts of phosphorous and potassium, along with calcium, magnesium, sulfur, and trace minerals. An application of ten tons per acre of compost with a 1-1-1 analysis, then, may add something like 200-200-200 pounds of NPK. An average vegetable crop harvest might remove on the order of only 80-20-100 pounds from the field. So, 120-180-100 pounds per acre may have been ap-plied in excess of what the crop harvest removed.

Since P and K are mostly held by the soil, it is easy to see how they can build up to high levels after a few years of heavy compost applications. Nitrogen is a dif-ferent story. It is easily lost to air or groundwater and builds up more slowly. So even after the heavy nutrient applications of these first few years, nitrogen will still be needed each year for most crops. P and K will be in ample supply. The soil fertility strategy can shift at this time, so the N comes mostly from legume green manure crops, and compost is used far less frequently.

Compost and Cover Crops for Organic Vegetable Growers

Brian Caldwell Farm Education Coordinator




Legumes for nitrogen

Tilling under heavy stands of legume green manure crops such as clovers or hairy vetch, can add over 100 lbs./A of nitrogen to the soil. The nitrogen content of a legume cover crop is roughly proportional to its dry weight content. This, in turn, depends in part on how much growing time the cover crop has had. In some cases, red clover may occupy a field for a whole year, but heavy crops of some cool-season legume crops, notably hairy vetch and field peas, can be grown before or after partial-season vegetable crops like lettuce, spinach, herbs, brassicas, onions, carrots, etc.

Another way of squeezing in a legume green manure is to underseed it into a standing vegetable crop at the final cultivation. For instance, red clover can be dribbled between rows of fall brassicas about a month after transplanting. By the time of harvest, the red clo-ver will form a low mat over most of the field. It will have competed little with the crop, unless conditions became very dry. In that case, extra irrigation will have been necessary. By the following May, a good stand of clover will put on enough growth to supply the N needed by the next crop.

Cover crops and green manures

Legume cover crops include clovers, alfalfa, field peas, hairy vetch, field fava beans, sweet clover, soybeans, cowpeas, etc. The clovers and alfalfa are perennial sod crops, while the others are grown as annuals in different parts of the season. Mixes of legumes and grasses often give the best overall results. Tried and true examples are rye and hairy vetch; oats, triticale, and field peas; and timothy and alfalfa or clover.

Two outstanding references on cover crops are the Northeast Cover Crop Handbook, by Marianne Sarran-tonio (1994), and Managing Cover Crops Profitably, by the Sustainable Agriculture Network, 2nd ed. (1998).

Crop rotation

During and after the first years of organic management, a good crop rotation needs to be put in place. The rotation is the key organic practice that allows pests, including weeds, to be controlled and soil fertility to be properly managed. Successful organic farmers realize the importance of their crop rotations.

The crop rotation can be seen as an organized succes-sion of crops grown over the seasons on a given field. It varies from farm to farm, depending on markets, soils, and many other factors. Good crop rotations, however, include a fairly wide variety of crops. In addition to vegetable crops for sale, an effective rotation further includes green manure and cover crops, and possibly even grains and sod crops.

Vegetable crops tend to reduce soil quality, since their culture usually requires bare ground over much of the season, repeated trips across the field, and they leave little residue. Sod crops, on the other hand, cover the soil completely and provide heavy biomass when turned under. Over the years, a sod will raise soil quality to its maximum potential. Cover crops and grain crops fall between these two extremes, in terms of effects on soil quality.

Sample simplified vegetable rotations:1. Intensive: Veg/cover crop → veg → veg/cover

crop → (repeat) →2. Extensive: Veg/small grain → small grain/

hay → hay (legume and grass sod) → veg/cover crop → (repeat) →

In the first example, a vegetable crop is grown every year, while in the second, there are two vegetable crops in every four years. Since vegetable crops are generally worth far more than grain, hay, or cover crops, the first rotation would seem to be more remunerative than the second. However, pest and weed problems are almost guaranteed to be worse in rotation 1, requiring far more effort and expense. So rotation 2, in fact, may make the grower more money. Anne and Eric Nordell of Beech Grove, PA have taken this extensive vegetable rotation idea to a very high level.

From a soil fertility standpoint, rotation 2 is also easier to manage. The cover crop used in rotation 1 will often be cereal rye, since rye can be planted late in the sea-



son, allowing for late vegetable harvest. Since rye is not a legume, it supplies no extra nitrogen to the field. Nitrogen must be added the following year for good yields, so most growers put on additional compost. As we will see below, on a continuing basis this will result in excess applications of P and K (and perhaps other minerals as well). Soil nutrients will gradually but continually build up in rotation 1. Also, the soil physical condition will be degraded by “lack of rest” from constant vegetable production. This will further increase the need for compost.

Rotation 2, however, allows for improvement of soil quality with a sod crop, and plenty of nitrogen from the sod plowdown. Other nutrients can be held at stable levels. In fact, if need be, P and K can be removed from this system by harvesting hay off the field. Little compost needs to be added into this rotation to maintain overall nutrient levels and soil fertility.

Organic matter levels can be high in either rotation 1 or 2. But rotation 1 will require continual additions of compost to keep them high. Over 20 years or more of production, P and K levels will become very high in rotation 1, but will remain fairly stable in rotation 2 if hay is removed from the field.

Other rotations can be designed that combine or alter various aspects of these samples, and may incorporate many of the wide variety of cover crops for nitrogen fixation and weed, insect, or disease control.

Phosphorous and potassium

Are very high P and K levels a problem? Let’s start with phosphorous. Fifty years ago, soil phosphorous levels were typically low enough to reduce yields un-less extra P was applied, so farmers said, “the more P, the merrier!” But after years of P applications, many agricultural soils now have high or very high P levels. Compost, especially poultry compost, is extra high in P, so this attitude no longer applies. When soil P levels get very high, small amounts of P will leach into groundwater and, in the long run, degrade lakes and ponds. This is not good stewardship, even though the overall phosphorous pollution contribution from organic vegetable farms is small. Soil high in organic matter is less “nutrient leaky” than those whose OM is low. But eventually levels can build so high that losses

will be significant. Adding excessive nutrients is also wasteful. In other words, it is not a good sustainable practice.

Oddly enough, even when soil P is in the “high” range, it is possible that some crops on some soils can be P-deficient under cool conditions. The crops will grow out of that deficient state when the soil warms. My suggestion would be to use row covers and other means to warm the plants and the soil if you want really early crops, and soil P will not be a problem.

Potassium is another issue. It can also leach into the groundwater, but is not considered a problem pollut-ant like phosphorous. However, very high K levels may interfere with plant uptake of other cations like calcium or magnesium. The science gets fuzzy in this area, but soil organisms may also not be getting what they need under very high K conditions. If your soil tests show continually increasing K levels, that also raises a warning flag.

Contaminants

Another aspect of yearly applications of compost that needs scrutiny is that of contaminants in the compost. Sewage sludge composts are not allowed for organic production, in part because of heavy metal contamina-tion. But this can be a problem in other composts as well. Some dairy and sheep farms use copper sulfate foot baths to reduce foot rot diseases. Compost from these farms has shown high copper levels. Non-organic broiler chicken operations routinely feed arsenic-based coccidiosis control compounds as well. Yearly appli-cations of such contaminated composts could lead to undesirable soil levels of these heavy metals. Be sure to review analyses of the compost you use for heavy metal content.

In conclusion

To sum up, I suggest that poor fields can benefit from heavy compost or manure applications for a few years. Once soil nutrient levels and biological activity are increased to high levels, a diverse rotation including vegetables, sod and cover crops has many benefits and avoids nutrient overloading problems.



I don’t have very many slides today; usually I bring too many. Also this is the first time I have ever been asked to talk on this subject. I think 90 percent of my talks are always on strawberries and they generally center around weed control, so it is kind of nice to have to think of something else to talk to you folks about. We will sort of plod through the pictures and I think by comparison to what I picked up out of Jean-Paul’s and what else has gone on here today, my talk will be very anecdotal on this subject.

In general, I would have to say that much of our farm is branded as certified organic, but I have never con-sidered myself an “organic farmer.” I consider myself much more a traditionalist in the sense that the part of the world that I come from, I come from a family of farmers that have always been farmers. It just has never gone out of our family. What has happened in my life is largely just a large part of chance.

The land I farm is very typical of New England. You will see from most of these photos that it is almost like we are in the middle of a rain forest the way the forest has crept back in around the edges of the field. Because so few people keep animals anymore, all the marginal land has just gone back to woods. All of the land that we farm is probably class-I and class-II soil.

As it just happens to us, most of the land that we farm due to our climate being in New England we get all

of this lake effect snow which becomes lake effect rain in the summertime and then we also get hurricane season that blows up from the coast. So, unless you are on exceptionally well drained land in the Connecticut Valley, at least for me anyway, since I am not on the really well drained stuff, I generally have too much water in my environment.

Also, the soils I am working primarily are silt loams, at least all of our level land where we do most of our crop production. Our biggest single crop is strawber-ries. It wasn’t what I had intended when I first went for my first career which was a chef. I decided that my farm was going to have three main enterprises all integrated in a really nice way. We were going to grow wheat, raise my bees and I was going to have small livestock, basically sheep. I was never going to have anything more than sheep and chickens. I spent my teenage years chasing my father’s cattle around the county and I never wanted to see another cow on my farm. As you will see as you go through this all of this has changed because really the way you were raised and what is in your genes I guess probably just tends to keep coming back to you.

This is a typical soil, typical field of ours with our biggest crop. We basically keep about five acres of strawberries in production and we have two types of production on the farm. We have our strawberry production and we have our vegetable production. In

Soil and Nutrient Management Practices on Upingill Farm

Transcript of a presentation by:

Cliff Hatch Upingill Farm

Gill, Massachusetts



one sense for years I have been trying to get out of vegetable production because of the low capital input it is almost where every farmer starts in our neck of the woods—with organic vegetable production. There is a lot of heavy price competition from people who haven’t been in business and don’t really know what it is costing them to be in business.

After a few years in the vegetable business one day I went to my cousin’s strawberry operation to pick strawberries and I went from being a leek farmer to a strawberry farmer in about twenty minutes of picking strawberries in his field and seeing hundreds of people coming to pick his strawberries for him and do his work for him I decided that that lonely work I was doing out in the middle of all that mud in November with those leeks was for the birds. It just wasn’t making it for me. I was in physical therapy for my back. Lots of stuff just wasn’t happening right.

We started with the berries big time in the early 90s and I really think the demographics in the strawberry you-pick is only going to get better as the population ages. You can see from these first few slides, after I go through my introduction of my farming, I am going to go into some of our strawberry cultural practices. I don’t have a lot of vegetable slides because since I always do strawberry talks, I have lots of strawberry slides, but I do have some of our vegetable stuff.

Our vegetable stuff is primarily field type things that we do now for our farm stand to decorate it in the fall. The bees have stuck with our operation. They are a real integral part of it. Partly because honey and bees have such a good image. What we are endeavoring is to get out of the certified organic trap that we are basically in as not being a big grower, we still need third party certification because a lot of our produce gets shipped to Vermont. There are some co-ops up there, but basically once our own retail business at our own farm is going well enough we hopefully can drop that oversight thing and just do things that we want to do. Having the bees on the farm and as a honey sales person it just acts as a really good all over thing with the public. It has good image. Not only that, I end up using some cover crops that probably some people tend to avoid.

We grow a lot of buckwheat because it gets us through the summer dearth on nectar in our cover cropping program. Also, it makes use of the clover and stuff

that we grow that we intercrop with all the rye that we grow for mulching the berries and stuff like that. We make sure that the bees are standing right on the hillside at the farm.

We grow a lot of vine crops as you can see. Our big-gest vine crop is not so much squashes, which are for our own stand in the fall, we grow a pretty good size melon crop. Primarily musk melons, but we are also growing watermelons, regular cantaloupes and some other exotic melons because now that our brand name is established with our melons in these markets we can offer a whole line of things and the melons kind of are paying the payroll for the summer labor that we need in our berries.

We have a lot of things happening on the farm at this point. One of the reasons we got into bees was that we had no land and bees don’t really respect the boundar-ies that everyone else has so the bees basically would do a fly over and bring back a crop for us.

When we first moved into the county my wife and I were both working in the city and we decided that we had to change our lifestyle and for raising our children. We were living between Boston and Providence. I worked in Providence, she worked in Boston and we split between the two and we saw each other kind of when we put the children in one another’s arms. We decided to leave that and come back to the small farm that she had grown up on. It wasn’t a farm when she grew up on it, it was just a hobby farm where they raised some horses. We started out with that and started renting little pieces of land around the town and then finally we got well enough established that people would trust us with a little bit bigger piece of land. I come from a farming family and basically I ended up selling farms in that town and using them as a land swap arrangement to eventually buy a bigger farm.

So, what we will go over when we get into the soil fertility management thing is what is happening as we start with the resource management of that farm trying to incorporate traditional stuff with that. What we started farming for was a better way to raise our children. That was our primary mission with our farm. That is kind of how the cattle have come into the pic-ture. Part of me rediscovering that cows weren’t so bad, but also that I don’t like feeding my children dairy product that we found in the store. I don’t believe that a homogenized milk product is at all healthy for you



as well as the other stuff, plus I have always wanted to make cheese.

My grandfather was an international grand champion breeder of Ayshire cattle from 1930 to 1950. When I went out shopping for cattle, I naturally explored whether or not I could get some stock that would trace back to the time when my parents and my heritage ruled the roost in that breed. We had our first Ayshire calf just this past year. My little son that came along rather late in life glommed right on to it. Of course the calf is growing a lot faster than him and he can not handle it now, but that’s all right. There you can see the start of our Ayshire herd with the other calf that was born this year.

You can see where our farm is situated. Those are the hives right between the cows up on the hillside. Our ultimate plan for this farm is that we will have horned cattle grazing on the hillside to sell that cheese at the farm stand. My plan is that ultimately we will keep doing vine crops, vegetable crops and potato crops for a fall farm stand along with raspberries that we are getting into and then the cheese is basically my winter operation as I am growing older. I find as I am getting in to my 50s that the field work that I used to do out in the sun just isn’t the greatest anymore. Hopefully, I am going to turn that over to people who are younger than myself and think it is a lot of fun.

This year we started putting in a food processing plant in the farm to sell more value added berries and other value added products to make my cheese in and to handle the milk and stuff. That will keep me busy during the winter. I have always had to shift gears throughout my career. It is no different now. Now I am going back to constantly try and remember all that stuff that my parents used to talk about with the cattle and they’re gone. I don’t have them to ask the questions of.

The other thing that we are doing is raising pastured poultry. It is always nice on a hot day in the summer time to start slaughtering chickens. All of these things work in. Our compost piles are basically fancy manure piles. They will range in everything from potatoes to some feed corn that may have gotten moldy with a large component of cattle manure and bedding all just put in a heap until it is has been steaming for awhile and once the action has quieted down it becomes safe to put on the fields. The pastured poultry has been a project to get other people involved on the farm. This woman works

for me, but this is sort of like the old share cropping situation. I will give you space to raise your chickens if you feed or help to sell them. She manages the front of the farm during the you-pick time. It has also been good for my daughter. It has been one of her big proj-ects. Believe it or not raising chickens can land you a $30,000 scholarship. She won a total scholarship to go to college with. One of the kickers when we were at this luncheon that they had, the chairman of the search committee comes up to her and says, “Oh, you’re the women who raises her own chickens.” She has been involved with Vicki doing this throughout. Vicki and I had always done the eviscerating and slaughtering and she does kind of the day to day management of the birds. She finally got to really get her hands into the operation with us, too. But, it is all part of what I think our farm is really about which is basically creating a good way to raise our children.

I still use conventional tillage. It is part of my tradi-tional attitude. It is kind of the only thing I know. It is also what I have and what I started out with. I try to be good about it in terms of field passes, etc. We generally try to do our plowing and our harrowing in one pass by using a clod-buster following the plow so that we don’t go back and re-harrow. We use pretty much the same method whether it is melons or potatoes, the only difference in the next shot is we prepare raised beds for most of our stuff because our soils tend to be very heavy and we have more than adequate rain fall. This is an alluvial deposit. There is a 20-foot drop between this deposit and its drainage basin. Our biggest problem in terms of structural fertility is generally too much water and not enough air and soil life created from that. So, most of our stuff we put into some sort of raised bed. We do all of our melons into raised beds.

We have traditionally used plastic mulch on melons and a lot of our vine crops. What we are going to now is doing a living mulch, but what we have been experimenting with is putting down our plastic in the fall. Putting down compost or manure in the fall and then laying the plastic right on top of that. We would have already previously drilled in rye. The rye comes up within the lanes in the spring and all we do instead of having to add mulch at that point is basically roll the rye down. It has worked out to be a nice system. We are also taking it to the point which we are going to try this year in our field where we do not take up the plastic and we are going to try making it go another cycle because the rye was interseeded with clover and



that clover is now what is coming up between the lanes in that plastic.

Our basic method is if we have to correct any nutrient levels at this point we probably would have done it through a broadcast application. Generally, we find with most of our soils that we almost always need to have an addition of potassium and our cheapest and most convenient thing to apply for that is Sul-po-mag. We are able to get that for about $225 per ton. It goes on nice. It does a good job for potassium sulfate and we generally put that on with our clover covers, etc. The strawberries in their establishment have a relatively low nitrogen requirement, which is kind of a nice thing for our key crop.

Also, as it ends up for us, in most research on strawber-ries you can’t make them phosphorous deficient. Most of our soils always test phosphorous deficient. Even on soils where we have gotten our organic matter ap-proaching five percent we have started to have some good indications of available phosphorous already there. Our silty loam soils, the way it is explained to me, that the phosphorous is there it is just hidden between the particles and it is not available. So, we are generally on phosphorous deficient soil which is the other reason why the berries are a good thing in our estimation with our soil. So, basically a broadcast application and then we make these ridges. If this was going to be a potato field, our potato planter does pretty much the same thing. We try to keep everything on the same system so that it can all be managed accordingly.

After we have created the ridges, we primarily use Wilson cultivators. We also use these for bed forma-tion as well, but we use basically the same system for hilling our potatoes or cultivating between things, etc. It is our main piece of cultivating equipment. On our soils what works for us is keeping everything up on these ridges. The only place where we do not do this in on the hillside slope that you are going to see in a little bit. This piece of land is Hartland silt loam. We grow potatoes on this land. This particular piece of land fell prey to a practice of previous farmers of always putting lime on their manure when they were spreading manure on their fields. The pH in this field was running like 7.5-8.0 which is kind of high for most of the crops that we like to grow.

A sideline that we were doing on this land that I don’t think is worth doing is we got involved in an experi-

ment. I don’t know if you are familiar with “re-miner-alize the earth” or not. Over on the side there is a pile of stuff with which we are involved in an experiment with some researchers at U-Mass and some people for The Publication for Remineralizing the Earth. What their thought was is that soils that have been farmed a long time had been depleted of a lot of their trace minerals. There are several big quarrying operations in our valley and a grant writer got the idea that we should take some of these mineral wastes from these gravel operations and see what would be the affect of adding these minerals to the soils. There were two types of stuff available. This was trap rock dust from the crushing of stones that they use primarily as schist whose key ingredient is calcium. We have that stuff available to us and then we have the float from a gravel operation where when they are washing gravel there will be all of these minerals that they want to wash out and then that becomes a waste product and they have all this cloudy stuff with minerals at the construction pit for you to go pick up for free. People were using that in the area also.

These researchers asked me if I would help them out. We used this in various ways and it actually did work very well against Botrytis in strawberries. But as far as raising the brix level of the fruit by applying this to the soil, no it will never happen. We applied it to grain crops instead of our cover crops. We did not get any results. The hypothesis was disproved. It is an inter-esting thing in terms of soil fertility. If you do have a quarry in your area that does crush rock and you can get it, what is nice about it is that most of our soils also kind of have a little bit too much magnesium in them. The Lee lime that they get in the Berkshires is a high magnesium lime and that is generally what is available in our area. Actually as a source for calcium without excess magnesium, different rock powders like this from various quarries do come in handy. This one had high calcium and would help buffer the soil’s pH but it did not add the excess magnesium.

The other thing in terms of approaching our fertility, especially with the strawberries and the other cash crops we rotate with strawberries is leeks. I can’t look at just my fertility as a single issue. I will not put any animal manures and especially my own compost stuff on this land where I am going to grow berries or leeks. We rely primarily on plant cover crops and then the additions of things like Sul-po-mag or black rock phosphate and pure minerals like that.



We have also gone to making all of our own straw because anytime we have bought straw it is almost like going out and paying for somebody else’s problems. We have introduced a lot of really nice German chamo-mile with New York State wheat straw into our fields at different times. You just create a lot of nightmares with that. Basically, 60 lbs of nitrogen per acre for the total vegetative year of this crop. That is not hard to make at all. We are planting at usually about 14,000 – 28,000 plants per acre. We do a delayed planting to help aid with our weed control in these and the crop just ahead of this was the rye cover crop. We almost always precede our strawberries with sudan grass the season before that. After that land is seeded with su-dan grass we will go through seasons of clover on the land before it is replanted to leeks. We will generally follow leeks and strawberries back and forth. This is one of the few things that I don’t think does anything bad to my strawberries. If I can get sweet corn, we are currently going in to having sweet corn at our farm stand. If we can get sweet corn to be weed free we will probably grow that ahead of strawberries also because as a relative of corn, etc. it would not vector anything bad to our berries.

The addition of the rye straw is probably the single big-gest source of organic matter. We are putting down an incredible amount of straw. We are putting out at least six tons to the acre every single year. The plants are there for at least two to three years besides everything else that we have plowed into the land. The production of our rye straw is a major undertaking every year. We are probably putting in at least 10-15 acres into the barn of rye straw every year. As one of our biggest crops and work activity, what we do is plant the rye in late August, September, October all the way up to November if we can and we basically interseed most of our rye, almost all of it with red clover. After we mow the rye in the spring we do not go back and have to do any tillage. The clover will come on. Hairy vetch does not recover from the mowing – it never seems to come back. I don’t know why, it just doesn’t. To me is seems like it should, the red clover will always come back.

The farm has two major resources, the one 14 acre flat field that you see going in the center field of the photo and there is another 10 acre field that we are contour farming which is where I am standing taking this photo from. I am standing in the middle of the alfalfa field that was there when we bought the farm.

Alfalfa, orchard grass with a lot of quack grass by the time we got it.

The 14 acre field is two types of soil. There is a Rayn-ham silt loam which is at the lowest parts of it and it has a Hartland silt loam in the upper part and the Hartland ranges out into some Merrimac at the extreme headland of the field. The Merrimac is a really fine soil for do-ing organic production on because it is one of those extremely sandy soils. The Hartland silt loam is real nice on this and it is the upper part there and that is were we are putting all the berries. Our first year with this field to get it started we did that center strip which you see plowed up the center of it. The upper half of that was the first place that we planted strawberries. That piece of land had been in continuous silage corn for about 15 years. The organic matter tested out in that field at five percent organic matter content. The farmer that I bought it from was a traditional guy with a lot of cattle and huge equipment to really put down a lot of manure. Our first year growing rye on that – the rye at the end of May, early June was up to about eight foot high and the stalks were so thick on it that the equipment could not handle the stuff.

The fertility on the field was incredible from this management, but the weed problems in it were also unbelievable in terms of everything that had been put on it. Every kind of broadleaf chemical had been used on the land and an entirely new family of weeds is always waiting for you each year. The years that we have been bringing this farm out of that kind of production to make it fit for growing strawberries has been a long hard climb.

This slide shows that whole center strip – those berries are now out of production and plowed under. We would have disked them over as soon as we were finished harvesting them in July. This is basically August/September when we are getting ready to sow our rye. You can see on the right hand part of the middle field just below that black section, that is one of the fields that we cut rye off of and it is basically all clover for the summer period before we plow it under again and plant rye on it. Just ahead of that you see two white strips going back and that is part of our buckwheat. I like to plant buckwheat. When I am first getting onto a piece of land I generally plant buckwheat on it just to assess what the land can do. If there is any part where buckwheat doesn’t grow there probably is some kind of a serious problem. The headlands in this field would



not grow buckwheat. There had been so much traffic for years of harvesting the silage and the plowing pat-terns of the field that the entire headlands at the further end of that piece would not grow buckwheat because of the soil compaction and also because there was a slope at the end that was bringing too much water into that part of the field. Between diverting it and growing various crops on it and going over it lightly we are now growing on that part of the field. There were a couple acres at the headland of that field that weren’t productive because of water and compaction and serious problems with that.

Over on the left you see a strip that went through our micro-cropping pattern which was to grow buckwheat to assess what it would do. I can generally get three crops of buckwheat into a piece of land in a single year, if I can, out of a single sowing before I plant rye on it for the winter. Rye or winter barley, either one. I will put on winter barley if it is quick enough. We have to get it planted before the first of October. We can’t really get a good stand of barley in our latitude if we put it on later than that. Anything later than that has to be rye.

The winter barley is a great feed for cattle, for pigs, sheep and any kind of waterfowl love it and most fowl love it also. There are a few dietary things you have to watch because it is very abrasive to the gut. You either have to soak it or grind it or something, but it is a mar-velous feed and it is pretty easy to grow. It threshes out nice. There again a straw from that I generally will sell to someone else after we thresh out the straw because it will be too weedy for putting back on our land. What we like to grow is basically rye hay. We thresh out virtu-ally none of the rye. We harvest it in early June when it is just headed up and once it is mowed it is dead and then the clover can come on in the field.

The center brown spot, where those stripes of white are growing is where we took out the planting of straw-berries and we will probably put you-pick peas in this strip next year because when we are up there picking berries people will get a hold of that.

The other thing on this farm is on this slope that you are looking at that we have planted, the upper part is still in alfalfa that will get plowed down next year and we will put field corn for grain on the top of the hill. There is a strip of sweet corn and then there are strips of sorghum and then there is buckwheat at the bottom.

There is also a strip of pumpkins in this contour also.

Now this backs up to part of our strawberry rotation you can see the buckwheat growing. As soon as we disked off those strawberries I usually put buckwheat on as a smother crop for weeds during the summer. There are still some berries in there that we are prob-ably going to try taking to a third year fruiting in that back piece and this is the group of berries that we just planted this year. That land before the berries were planted had buckwheat on it for two years with rye covers in the meantime. Last year it had a crop of sudan grass with cowpeas and other things on it that we plowed down. The rye was on it right before we planted it and that is the other reason for our delayed planting because we will take the rye off and then do our planting.

Generally, what we have been using with the demise of Agway is they had a lot of fertilizers that they bought when they wanted to get into the organic produc-tion business and I did a pretty sizable purchase of a chicken fertilizer that they had put together. It includes everything from manure to chickens, body parts and everything that they manufactured to sell to organic farms. With their bankruptcy there was a big stock of this at the local fertilizer plant that I bought up. We have bought that and used it for top dressing in things like our renovated strawberries, this was 6-6-6. In our renovation of strawberries if our nitrogen levels are low we go out and buy it in some form like that.

We have not had good luck on berries doing things like using alfalfa meal and soy. We have done that in years when all of a sudden there was a problem. I am not sure exactly what was going on in those fields where we used a feed ingredient as a fertilizer, but I never had such problems with a crop as I had when I used that and I can’t explain why. The plants were anemic and it came on suddenly. Tissue samples showed nothing. We had no nutrient imbalances of the major things, anyway, but they just weren’t thriving. It is possible it could have a seasonal thing. It was kind of a cold, wet season. But, it was the only thing I had done differently from anything that I had ever done with berries before. We had other berry plantings on the farm that were doing fine but the field were we put our combination of soy meal and Sul-po-mag, because they were the only things that would match organic certification that the local fertilizer mill could put together for the planting and because they had run



out of what they had that was NOFA approved and so they made that up for us. We applied that and used that as the fertilizer. Broadcast, did our hilling and usual things and then halfway through the season, basically when it was time for them to run and vegetate they just stopped. There were no nematode problems, there weren’t any of those other things that there should have been and that was the only thing I changed in my management. This is back in the days when we used to raise several acres of leeks. The same soil, this is our key crop that we like to integrate with our berries if we are going to grow another cash crop on the land with them and work in as a rotation this is my preferred thing with that.

We irrigate on our land primarily for frost control where we very seldom have to put down water for water sake. It is usually not necessary. We have had one or two seasons where I have watered crops for fear of losing it to drought. Generally, if we are watering we are either evaporative cooling which we will do on potatoes a lot, especially in the summer. Potatoes like to be cooled down in the afternoon. They don’t like hot days they like to go in to the night cool. We will water at midday on strawberries for evaporative cooling and then this past year we got to spend many sleepless nights watering all night long to keep things from freezing. That is winter barley in the foreground of the photograph. This is probably just immediately after setting plants and we are watering them in once they have been set in the raised beds on there. The only place we really do not do that creation of the ridge is on that contour.

This farm as you can see from this wet area that is running right through the center of the field were there is a lot of hazel wood growing etc. In terms of what it points out to there, saturated soils like that in a low spot are virtually used as grazing land. There really is nothing you can do with them in tillage. They are better off as a resource just left. Even grazing them at the extreme banks is a problem. Then the strip go-ing up the hill, the lower part of that strip we used for vine crops and then each edge of the contour on it, basically on the left edge we are raising raspberries, we have a perennial crop that does not require any tillage. Because it is a small part of the field it would be difficult to be turning a tractor in and around. We plan to do pastured poultry also on that section, put-ting the poultry in amongst the raspberries on that as

a way of keeping weeds down and putting stuff right back in to the land.

You can see a crop of sudan grass and above that you can see the corn. Next year where that sudan grass and corn are will be re-seeded into rye and red clover over the winter and then where the alfalfa is at the top will be plowed down next year and field corn will go in up there. This is another shot of the same thing except, I don’t know how evident it is to you, but the key things we have had to do on this farm is the drainage. The drainage ditches that were in it are all filled in. It is our biggest thing. Soil that is holding too much water has no life in it. That strip of buckwheat is for a new plant-ing of raspberries next year. We broke the sod on that hillside two years ago, put it to rye and the following year it was in a summer crop of buckwheat and next year it will be civilized enough and the sod broken out that we can put raspberries in there.

I am happy to take a question at this point of anyone has one.

Questions and answers

Q: I find that rye can be a problem to handle. How do you manage it for the least problems?

A: Likewise with you I have had rye in all kinds of forms. The worse problem with combined rye is that it has too much rye seed still in it. Most growers will not reset the concaves and get the grain out of it. It is a pretty small seed so you end up with tons of rye seed and rye since it doesn’t winter kill like oats or something like that is nasty stuff to have as mulch if it is really rye straw.

The other problem with rye if you use combined rye is that they don’t thresh it until late July or August. It takes a really long time for the seed to get to the point where they can combine it. Generally, you have a lot of other weeds in the field. Unless they are using a really good herbicide management plan on it most rye straw will be infested with weeds and more rye. My experience lately has been, like with this field that has had so much high fertility and grows such rank rye that my machinery can’t handle, I cut it fairly early. You cut it as early as you can when you have



the weather in your side. At our latitude basically from May 30th on if there is enough crop in the field to make a crop for you as far as what you want, cut the stuff. The earlier you cut it the less weed seed you are going to have. As soon as it heads up. If the head has formed it will not regrow. You can wait until the cuticle on the leaf dries down if you want a stalk on it, but the other thing you have to worry about is if you let it get too high.

If you take rye that is grown to eight foot and on re-ally good land rye will get up to eight foot high with no problem, by the time that goes through a hay baler, unless you have got a chopper, you go to shake the stuff out you are going to have strands like this that you are trying to put down around stuff. It will be a very poor mulch. It won’t keep any of your weeds out either. I used to mow it myself with a disk. I have a disk mower. Now I pay the farmer next door, who since the local straw dealer went out of business the dairy farmer next door had taken to growing rye and selling it. As he is cutting his rye I have him cut it with a disc-bine. He has a flail conditioner after his mower which pulver-izes the stock so it dries better. We have a chopper that chops it. We put all of our rye through a bale chopper. We have a trailer with a chopper mounted on the front. We load the trailer with about 40-50 bales and the chopper is out in front and we just throw whole bales into it and it chops it up. The rye hay is no problem. That is one advantage that combining has is the extra between having gone through a combine and then go-ing through a baler you could generally hand shake it out and it is not bad. The rye hay is really nice if you have a chopper to do it. We flail condition it. The other thing you can do to make it easier to handle is let it get rained on a few times. Don’t worry about it, let the stuff get rained on it will help break the cuticle down on it. Just rake it again, dry it out again and then bale the stuff. Your baler will probably handle it a lot bet-ter, too. Because it is so waxy, most balers, unless they have straw tuckers, the baler can’t handle the stuff. It goes through too fast and it is a weird adjustment you have to make on a hay baler to handle that stuff, but most people who bale straw have special bale retarders in their balers to handle a waxy cuticle. I know that is kind of an essay answer to what you thought was simple question.

Q: Why do you use rye if it’s so tricky to manage?

A: A couple of things about it. Number one the rye is cheap. Rye is going to run you about $9 to $12 for 50-100 weight, depending on how you are buying it and it is untreated seed they do not put any work into it.

Compared to other species, most other species of cereal grains they have developed have very low amounts of straw and very high amounts of grain. Most of the rye we plant as cover crop is still primitive in that respect and has a massive amount of straw compared to the amount of grain in it. The barely that you saw in that other shot, if we get a couple of tons of straw off an acre we would be doing really good where as we can probably get six tons off any acre of rye easily. Because it is just that much more product in straw compared to the grain species. Most of the wheat that you see grow-ing out in this part of the world, I guess it is actually called Geneva, which is the principle soft wheat grown in much of the northeast now. The stuff doesn’t even get to two feet high and it has these huge seed heads on it. It is a very highly bred plant. It is bred for grain it is not bred for producing straw.

Plus the rye will also germinate. No matter how late you are in your management you can put that stuff on in the middle of November and it can make a catch. It is a really remarkable plant. The other thing that we do with it is the rye was planted on this contour and you can see that it is gone now. We have our rye down on our berries. We put these guys out on it, too and they were making a remarkable amount of milk on it. It is really incredible how much milk they make on a bin of rye.

Q: Do you have any problems with pests?

A: We have a lot of problems in our organic berries with strawberry rootworm, it is our biggest pest.

For tarnished plant bugs I can tell you what not to do. We do scouting and we put in a lot of traps for captur-ing them. Don’t leave rye standing or any weediness or aging plant near them. I’ll relate the worst experience we had with tarnished plant bugs this past year. I left a strip of rye standing near a stretch of strawberries, hopefully to act as a windbreak and create a nice little microclimate to boost those berries along because they were a late variety and I wanted them quicker. We never had such an infiltration of tarnished plant bugs as we did in a patch of strawberries with a wintered over



crop like that left standing beside them. It just was an enormous pest gatherer.

Q: Are you sure it was the rye?

A: Well it could have been chance because also there is a strip of rye between them and a hay field and the hay field also could act as basically a reservoir for tarnished plant bugs, the hay field had alfalfa and other species that tarnished plant bugs like and I have tried putting reservoirs of alfalfa near strawberries but tarnished plant bugs just love that little white blossom they will always come over and get some.

Just as well we have to watch for tarnished plant bugs whenever we are using row covers because the row cover will boost their populations also. They like be-ing under that row cover it helps them out just like it helps the berries out. They are a major problem. Cold is your best asset against them. Early fruit doesn’t get bothered by them as much as all of your late varieties. Jewels, Late Glows and all those things and there is very few effective organically approved pesticides that will be effective on tarnished plant bug.

We do not have any problems with root weevil. The strawberry rootworms we can’t really live with. I have tried various management strategies and I thought I had figured it out, but this past year I got another infesta-tion after having gotten rid of them for awhile. I look at that as a syndrome. Usually we get a strawberry rootworm problem whenever I damage some roots on some strawberries and in this case I hit them kind of hard with some cultivators when we were renovating. It was a dry time and it was just this one section I did not feel like resetting the irrigation to irrigate this one little patch and those stressed plants got a patch of strawberry root worms in them who have proceeded to try to take over more than I think that they have any right to have.

Q: What varieties of strawberries do you use?

A: This is supposed to be soil fertility and it turned into another strawberry lecture. What varieties of strawberries, for what?

The way you can always tell the ones that are good for production are they are usually the ones that are the lowest price in the nurseryman’s catalog because

they have been around the longest and growers have bought them the most.

I am always kind of a “contrarian” and I always was buying more exotic ones and pricier ones and I never had such good luck as when I bent back to getting something like Honeyoyes which are a good New York State development. They are the most productive strawberry I grow or that I think anybody can grow. They are a good sturdy plant. They are not good when they get over ripe, but they have amazing production. They’re a good plant maker because in strawberries for organic production the key thing that you are going to want to do is be on a nice light friable soil that you can do a lot of hoeing.

Unlike most other things, to get strawberries estab-lished in a weed free way, if you want to get a couple years production on them. They are really devilish on weeds. Strawberries don’t mind other plants they have no bad will against any other plant. They think that growing in the edge of the woods in a bunch of weeds is just where they belong. They appreciate the shade that they get from other plants. The only way being able to counter their whole thing for organic production is to increase their planting density so that they are shading one another and keeping each other cool because that is what they really like. They like nice cool roots. I don’t know how people get them to survive in plastic. I have never seen strawberries that I thought looked happy growing in that stuff. Nice well drained soil that can be cool like a north slope. If you have a nicely drained north slope and you have eradicated the perennial weeds in it to some degree something like Honeyoye.

Honeyoye is a really nice berry, but in strawberries it is going to depend a lot on your marketing and how you are selling them as far as what will go well. Honeyoye is a good all over berry. Cavendish works really good for you-pick operation, but it does have some white fruit problems. The only ones I would probably tend to avoid for organic operations are anything that is sensitive to leaf spot. You probably should avoid these because even the copper based fungicides which are the only thing you really have in an organic management program to fight leaf spot with are extremely toxic to strawberries. They just don’t like copper. If you have bad leaf spot on a plant and you’re not able to control that fungus, if leaf spot gets onto the calyx it makes



very unattractive fruit; nobody buys it. They don’t care how organic it is. They’ll hop over that fruit with the damaged calyx, won’t sell in anybody’s market compared to something with a nice looking calyx. So a Midway would be one to avoid in that respect.

In conclusion

I have arranged this one as the last slide as far as the cows out grazing on the cover crop. It is incredible with them. I had always been told by my father that rye would make the milk stink and not to graze your cattle on it. You couldn’t keep them off of this stuff. They would wait at the gate and would much rather be out there shuffling through the snow than eating something else and the milk didn’t stink and the butter was extremely yellow.



Soil and Nutrient Management Practices on Roxbury Farm

Transcript of a presentation by:

Jean-Paul Courtens Roxbury Farm

Kinderhook, New York

I caution you that everything you heard today you will hear again in a different way. So hang in there, there will be some repeats, but hopefully some practical application on what you already heard by the other speakers. I noticed some different approaches on fertil-ity management here and there. For example, Harold differentiates three qualities in determining soil fertil-ity. I distinguish one more, and I make the case for a fourth quality, which is called structural fertility. I see this as a quality that in itself needs to be recognized.

Let me walk you through these four different qualities one by one. I will start with chemical fertility.

Chemical fertility

I realize we mostly concentrate on vegetables, but I like to mention that when maintaining the chemical fertility of our land, the hayfields are usually much more self-sufficient than the vegetable fields. I think this is an important thing to notice.

But first let us look at the composition of different fertilizers. I gave you a handout (pages 45–56 in this proceedings). By the way, there is no way that I will be able to cover this handout in one hour, which is about eight pages printed in a very small font type.

What I like to point out in the first slide is the analysis on one of the tables of our own compost made from dairy manure. The same table is also in your handouts. As you can see here compost is a much drier product than animal manure, and you can compare the numbers as far as nitrogen, phosphorus, and potassium. Since the compost is made from cow manure, they are rela-tively comparable. The numbers go up a little bit when made into compost. The number that is considerably higher in compost than in manure is the organic and the dry matter, which I think is fascinating. I always won-dered about how the dry matter can contain so much more than organic matter, but I just have to believe the analysis. What you have to realize with the nitrogen in the compost, is that it all consists of nitrates, while the eleven pounds of nitrogen in the solid cow manure is half ammonia and half nitrates. I also have some numbers here of pigs, chickens and horses.

The other thing I wanted to point out is that the poultry manure analysis shows high phosphorus levels. When you look at the needs and fertility requirements for vegetables’ development, its needs for phosphorus are kind of low, so we don’t really need poultry manure and in general we could be quite happy with compost made from cow manure coming from animals that have not been fed grains. High phosphorus manure comes from the very high grain diet animals consume. So, you will see phosphorus numbers go down for an animal



that is being fed less grain and lives mostly on a diet of grass and hay.

Physical fertility

I was in the interesting situation that I had to look for a new piece of land. This is interesting from the perspective of assessing land for its physical fertility. I had to put myself in the shoes of a new farmer. What do you do when you look for land? The first thing I did was obtaining a soil map from the soil and water conservation service. It shows you where all the good land is in your county, in my case Columbia County. Those soil maps showed that a lot of good land, all the class-I and class-II soils, are located in Kinderhook. What are class-I and class-II soils? It tells you how they behave, but it does not always mean that they are suitable for vegetables. Some of these class-I soils are actually flood plains and frequent flooding does not go well with growing vegetables.

One of the most important aspects of a physical qual-ity of a soil to be suitable for vegetables is that it has to have a high carrying capacity. In other words the ability to drive your tractors on them. When one inch of rain or more doesn’t prevent you a day or two later to get back on there. With a clay soil you are not be able to do that. You have a very narrow window to get on there with your tractors – it can drive you crazy. Another aspect is good drainage and is related to the first. You also have to have good access to irrigation water, and a good deep A-horizon or what we generally call the topsoil. These things are all physical qualities. These are all things that are very hard to change, and the list goes on.

When you determine the physical qualities of a piece of land, you should accept those as they are, without the notion that you are going to change it. If you have a lot of rocks in your soil, you have the option of buying a rock picker. It is going to take a lot of time, a lot of money and many resources to get these rocks out of the field. In the end it is a lot cheaper to buy a piece of land that does not contain any rocks to begin with. If you already have a piece of land that you might have inherited, you come to realize there is a cost involved in making it suitable. If the slope exceeds, say, two percent you could bring a bulldozer in. You could level

it. Again, there is a huge cost involved in it. I happened to be in a situation, about ten years ago, where some-one came to me with just such question. It involved a corporation that wanted to have an organic farm as part of the business. They invited me to consult with them and said, “We want to grow vegetables here.” My initial response was, “No, you’re not. This land has too many obstacles.” And they said, “Oh, yes, we are.” I did not realize the amount of resources that this particular corporation had to make it work. And they made it work. So, it is not that it can’t work, but nobody in here at least, has the resources to do it.

When it comes to the physical fertility of the piece of land, you can’t make too many changes. I like to relate to the physical qualifications of a piece of land like the genetic code we inherit. Assume that you found a good piece of land. It is flat and has other positive qualities for growing vegetables; you still have to determine what kind of land it is. Is it a sand, silt, or loam soil? I tried to compare those soils to a riding or a work horse. The riding horse is going to be the sandy soil, you get there quick. It is a means of transportation. They pro-vide you with early season vegetables. The workhorses are the silt loams. They give some real production all through the summer. It has a much larger window of getting through a drought.

So, in short, if you want to grow vegetables, try to get the best soils you can get your hands on in your par-ticular area. In Massachusetts, the best is a Hadley silt loam; in Columbia County, it is an Unadilla or Occum silt loam. I have no idea what the good soils are in this area, but good land is the best place to start. We found a good piece of land.

Structural fertility

When you talk about structural fertility, you define how all of the different soil particles are connected and organized in relation to each other. When you want to evaluate the structure, you imagine a circle and draw a line through the middle; one half of it contains the pores in your soil filled with water and air with the other half containing the mineral component. That image is true for good vegetable land. It may not look like that for grasslands or for croplands, but especially when growing potatoes and onions you aim for a relatively



fluffy soil. You can achieve that with equipment, but it is much better if you can accomplish that with other means. A good structure means it has a good ability for roots to penetrate, therefore a good ability to hold water and to drain water. Now again, all of this has already been said before today. I feel like much of what I prepared to say today is a repeat, and I will try to move into the more practical applications of every-thing we are doing at our farm. One thing that I might add and I haven’t heard anyone mention today, is that when you have a clay soil, and I do not recommend this for vegetables, you can improve it by altering its chemical component to give it a better structure. When, for example, the clay contains low amounts of calcium, it will start losing its natural structure, it becomes unstable.

When we talk about tillage, I mean when you are working your soil, a rule of thumb is to take a lump of your soil in your hand and drop it down from four feet high. The natural breaking points of your soil allow this lump to be broken up in smaller pieces. This is a guideline how hard you should work your soil. Soil should have a composition that is build up of natural aggregates. Soil aggregates are relatively small, since you can hardly see them, but they make up the natural composition of your soil and are created by root ac-tivity, microorganism, and earth worm activity since they break up the soil, and through digestion glue soil particles of different sizes together. You can disturb this natural formed aggregate through the use of a tillage tool to create a seed bed when this is done in a violent manner. A rotovator is such a violent tool. What can happen is that these tiny aggregates, which we have seen some beautiful pictures of today, are falling apart. The consequence is that after a heavy rain storm the sand, the silt or the clay separate with the smallest particle floating to the surface, which causes crusting. This will have a detrimental effect on the quality of a seed bed. Root activity is a very important tool for soil improvement. I will talk more about that later. Biody-namic preparation 500 is another. Repeatedly, research shows that where the Biodynamic preparations have been used the soil shows increased microbial activ-ity, and rooting depth of the plants. The homeopathic medicine that we use on our land has a real impact on its structural fertility.

Frost tillage is a common used tool in Holland in re-gard to light clay soils. I am not highly recommending the use of it in this country because of the timing of

the plowing which has to happen in the Fall. Given our winters and slopes, exposed soil over the winter causes too much erosion. Harold showed a slide of how we were taught to plow back in Holland. The furrows were supposed to be nice and straight, and shiny. There was this whole idea about this shiny fur-row that rested over the winter and after that it was beautifully broken up by the frost Only later did I learn that it was about the worst plowing job one can do. The Nordell’s showed me the benefits of turning the soil only slightly without completely turning it over. When you make the choice to expose the ground and loosen it up before the winter it is amazing how that can change its structure. One trick that a lot of people may not know about is that you can cause the same effect over the summer. Over the summer when the soil has become extremely dried up, you can put your overhead irrigation on and drench the soil. This will fracture the soil as well.

This slide is an example of some good soil. This was a crop of rye being spaded in, and this is what you want to be looking for when it comes to a good structural fertility. The decision to take a field out of vegetable crop production is based on what I see. I do not have any tools available for me to know how the fungi actu-ally hold the soil together, but you can see it. You can see in this slide that there have to be a good amount of mycorrhizae and other microorganism that hold the soil together. At the moment the soil becomes blocky and has straight edges, I know it needs a period of rest. I need to take it out of production. I have been working it too hard. Soil should never feel hard on your hands. It should be soft. It doesn’t matter if it is clay soil or silt loam soil while it is very hard to create structure on a sandy soil. It is extremely difficult. It just doesn’t have much to it. After incorporating a lot of organic matter on a gravely soil it will still feel hard. When it comes to the better quality soil, the silt loam and the clay, they can really feel soft to your hands.

Aeration incorporation, and seedbed preparation

Aeration is important both for the breakdown of the organic matter to release nitrogen, but also to create more pore space in your soil. Proper incorporation of organic material is a very important thing if this involves large amounts of organic matter. If you can’t incorporate it properly, it can’t properly break down. It has to be distributed into the soil. We need a quick



breakdown in the process of creating a seed or plant bed. The moldboard plow has no use on our farm any-more – (showing a slide of land being plowed). This is an old slide, since it has been rusting away on our lot for it hasn’t been used for a long time. The reason why, is when I noticed that the kale or corn stalks that were plowed under were still there buried in the ground at the end of the season. Nothing happened to them. You want to plow under, say, a tremendous crop of Sorghum Sudan or anything comparable. What are you doing? You might be creating silage down there. Is that the point? It really doesn’t do a lot of good. The moldboard plow makes a beautiful seedbed though, because it doesn’t take much but a pass of a disk and we are ready to seed. The plow makes the land look nice and clean. It buries all this organic matter.

After this, we went into a stage where we used the chisel plow. The chisel plow is a wonderful tool and we still use it a lot. It is a fast working tool. I like anything that can work up an acre of ground in 20 minutes or less. This width of the chisel shown here is about seven feet. The problem with this tool is that it leaves a lot of the plant matter relatively close to the surface (Harold would say this is a great thing), well, for vegetable growers it might be a problem if you don’t have the right seeders. It will demand several next passes of discs and harrows to create the right conditions. I am trying to stay away from the disk completely because it has a tendency to cut the soil. It can cut the aggregates in pieces, while the s-tines have a tendency to find the natural breaking points. They rather hammer the soil all the time. This is the process of creating a seedbed.

The problem with this system is that you need to make many passes on your field, going back and forth, back and forth. First you go over it with a chisel plow, then with a disk, then with a Perfecta and then finally with something that makes a seed bed to make it nice and level. That is four passes. You have aerated the soil all right but you compacted it again by needing to create a seedbed. This felt very silly to me. So, a couple of years ago we purchased a spading machine, although I was forced to, out of the practical situation we found ourselves. The lease on our land had been terminated. I had to produce the following year and needed to find certifiable organic land. All the good land I found was in corn, and given the herbicides used, I could not grow vegetables on that land. The only land I found that would work was in sod. I had to get rid of a lot

of sod and I wondered how I would get a quick break down. Moldboard plowing was one option. The chisel plow wasn’t. I chose to spade the sod in the spring for vegetable crop production that year. It worked. It proved to result in a very quick breakdown of organic matter by distributing the organic material.

Here is an example (showing a slide of a spading machine), of what the soil looks like when you spade in sod. Extremely effective, mainly because of the secondary tillage action following the spades. This is not a machine that pushes the spades straight in the ground, which is preferable. This is a rotating spading plow. It moves very slowly. It is not at all like a rotova-tor. It picks up big clumps of soil with organic matter and it inverses it into the soil. You can set it anywhere between six and twelve inches deep. You can go rela-tively shallow with it. But the tool, the power harrow that goes behind will push all the bigger clumps deeper down. So, if you don’t go over it again with a harrow and bring the clumps back up again, those clumps will stay deeper down and not interfere with seeding. If you wait long enough they will be decomposed by the time you seed. A problem when plant matter stays relatively close to the surface is that it will not decompose, since decomposition needs moisture.

(Showing a slide of incorporating full grown Sorghum Sudan) We also wanted to see how much we could do with it. This is a full grown crop of Sorghum Sudan. I wouldn’t recommend it. It is just one of these things that we wanted to know what we could do with it. Under normal circumstances you would flail mow this Sorghum Sudan crop and then spade it in because, especially when the ground is a little on the wet side, it will wrap itself around the axle of the spading plow. It has also proven to be a good tool as far as looking at the whole farm system. We grow thirty acres of vegetables but can still look at it on a bed-by-bed case. As soon as the beds of squash are done harvesting we can spade it in and by the next day come in and plant a crop of lettuce. You can see here (showing a slide of a mulched crop of summer squash), with technology, this is what it was before – this is not a trick picture. We went over it exactly one pass.

Question: How many horsepower do you need to run the spader?

72 horse power for a two-meter spader. This is a heavy machine. The nice thing about the Italian models is



that you can do some real deep tillage with a much smaller model tractor. For example, comparable to a chisel plow in order to cover the width of your tractor you need a much more powerful with four-wheel drive compared to the same width with a spader.

Question: How is the rotating spading plow dif-ferent from a rotovator? They look like they work the same.

Looks are very deceptive – I have to go back to the slide where you saw the rye. We dug the rye back up after it was spaded in. The integrity of the soil was still intact. When you talk about any particular fertil-ity program on a farm it is really about preserving integrity. A rototiller or a disk invades integrity much stronger than this particular spading plow. All of the things that you see moving around move relatively slow. They take big chunks of dirt in the front and throw it backwards.

(Showing a slide of a bed former) We need to make one more pass to make a seed bed for carrots and salad mix with a bed former. We have a system where our tractor wheels are spaced at 72 inches apart, which allows for a 54 inch raised bed top in between the tires. This raised bed former was made in Ohio for tomatoes. They have a whole culture of plum tomatoes in Indiana and Ohio and they grow them on raised beds. It works very well for creating a fine seedbed. The tool is based on S-tines, staying away from disks as much as I can. S-tines will not pulverize my soil as much as the pan behind it will. It unfortunately kind of smears over the ground and every time you smear ground you are rubbing these aggregates apart. One thing you could do if you take the soil and rub it in between your hands you can see a discoloration there of the soil. That is how you can see where the particles are coming apart where the soil was one particular color before, you rub it between your fingers, and suddenly you can see all these other colors on your hand. That is because the sand, the silt, and the clay are becoming separated from the organic matter. This is what you do with tillage equipment.

Biological fertility

A lot has been said about this already today. I will go into the practical applications of it. I will let you read

the handout at home when you have the energy.

The important part in fertility management for us is based on cows, or on other large hoofed animals. Maybe a little bit too much emphasis has been put by biodynamic agriculture on cows. They definitely have a role but other large hoofed animals can make similar contributions. I actually like sheep, especially integrated with vegetables. I like them a lot better than cows, since cows are incredibly heavy. I have tried it. I have had my cows graze some cover crops but I will never do it again. The ground is so soft in the veg-etables they sink right in there. Sheep are much lighter.

The point of keeping large animals is that we need their manure and turn it into compost. I would never consider applying fresh manure. Manure is an unfin-ished product. It is half way there. It is great though. It is the first step in the process of decomposing plant matter. I feel that the cow adds a lot of qualities to the plant matter. The inside of the cow is like a plant within an animal. The inside of the stomach is filled with microorganisms that break down plant matter. When it comes out it is a very volatile product, because it is not completely finished or stable. You have to be very careful with it and if you do not treat it right you will lose many of its positive qualities.

In this particular case (showing a slide of a manure pile) you see that the material is being brought to a pile and then we mix it with horse bedding. Most of the cow manure that we are getting is on the wet side so we have to make it dry again with horse bedding. The particular person I am working with at Earth Works, Bob Walker, has all kinds of materials that he makes into compost. He uses cranberry pulp and any other organic material he can get his hands on. He needs to figure out the correct carbon nitrogen ratio when he has those materials in front of him. He looks at what he’s got, determines what will make the correct C/N ratio, and then he mixes them all.

He uses a Sandburger turner (showing a slide of the Sandburger turner) from Austria and its inverts the pile. Whatever is on the outside goes to the inside, whatever is on the inside goes to the outside. After it has gone through the turner it has become a much more homog-enous product than before. We add the biodynamic preparations to our piles. The way you can look at a compost pile is to think of having another animal on the farm. It is not a true analogy or true metaphor but



just an attitude type of thing. It is like an animal since it has all the qualities of an animal like body warmth, moisture, organs (by adding the biodynamic prepara-tions), and a skin (by covering it with the covers). I obviously actually take this very literally, but I do not ask you to do that. The Valerian preparation should function as the skin. We find that it is not sufficient enough especially in our climate where thundershow-ers can bring down two inches in one hour. The skin we are providing is a cover made out of a polyester type product that sheds the rain (while still allowing it to breathe).

Rain can be a tremendous enemy of a compost pile. Once water saturates the pile it will stop the compost-ing process. On the other hand, it also prevents it from drying out too much. You can imagine all that heat, you can see here it is about 150 degrees, will dry the pile out quite a bit. We use the same turner either to cool it down or when it is too dry to insert water. We can spray water into the pile. Other places where the analogy between a compost pile and an animal hold up is the following. When you have a cow, you check on it every day, right? Well it is somewhat similar with a compost pile. You kind of look at it, you follow it. You don’t have to feed it that is the nice thing about it. But, you do have to give it water and you have to monitor what the condition is. If you are going to do a good job, it will be free of pathogens, it will be free of weed seeds, and ultimately if you do a good job, it will have disease suppressant qualities.

(Showing a slide of a table of organic residue per crop) A most important contribution of compost is in raising organic matter effectively in comparison to cover crops. In your handout, I added the information of what ten tons of compost adds in organic matter, which is not on this slide here. It is very interesting when it comes to numbers. When you apply ten tons of compost each year in comparison to what these dif-ferent crops are doing, you can see the winners of all crops are three years of a grass clover mix. But all of this organic matter is relatively fresh organic matter at plow down. Ten tons of compost results in about six and one-half thousand pounds of organic matter per acre. This is a substantial number, especially taken into consideration that after one year most of this is still going to be there. Even after growing three years of a grass clover mix; only a third of the organic mat-ter is left after one year of breakdown. Most of it gets broken down.

Also, this table shows that growing vegetables is detrimental in maintaining organic mater levels. At least two or three percent of the organic matter is be-ing burned up all the time through cultivation. Not only the nitrogen but also the organic matter is being mineralized. So, if you grow onions year after year you could see that you are in a rapid declining state here. Maintaining organic matter is done somewhat if you put a field for one year in clover. It is much bet-ter than doing nothing, but all you replace is about a thousand pounds of organic matter. How much is that really? That thousand pounds of organic matter is ap-proximately 1-2% of the total organic matter reserve in your soil.

(Showing a slide with a table showing increase of or-ganic matter by sod and rapid decline following by crop land) Most of these tables are based on the Bemesting en Meststoffen textbook. It is translated in the table in your handout. It shows total organic matter. I find this a fascinating table because you can see how long it takes to build organic matter. Now look at that number 50. That is tons per acre. A little different numbers than what John showed us. I think John showed us a table that was based on 6 inches. This one is based on 12 inches of topsoil and in 12 inches of topsoil, there is I think 2000 tons of soil or was it 4000 tons. But anyway, 50 stand for about 2.5% organic matter if you want to convert it. So, we start at 2.5% and we are going to go up to approximately 3.2%. Over a period of 25 years, this is if you have it in continuous sod. So, we are talking about going from 2.5% to 3.2% by having it in continuous sod. The formation of the prairies, you can now imagine how long that took. It is a slow process. So here, we are considering growing cover crops to raise organic matter. That is a great consideration, but what we really need is 25 years of sod. And once we go back to cropland we are back to where we started in 10 years. So to maintain organic mater levels, and I do not know if I go out on a limb here, does that mean then, that out of every one year of cropland you have to balance this with 2.5 years of sod? Well that is where I think the compost has its place. The compost will effectively maintain the organic matter. I caution you though that too much compost can have negative effects as well, (like raising phosphorus to levels that it will pollute the ground water).

(Showing slides of a crop rotation) What I want to do next is to go into some crop rotations. My crop rota-tions have many cover crops in them and you might



ask why I bother. I just showed you that cover crops don’t increase organic mater levels. Well it is not so much the objective of raising organic matter when growing cover crops. The reason is more in support-ing structural fertility. I have not seen any evidence by spreading compost, that I am supporting the soil structure. I have not seen the relationship between adding a lot of organic matter and increasing the soil structure per-sé. Especially not if I raise vegetables in a very intense way accompanied by an intense regime of tillage. I have grown two crops, sometimes three crops a year, which requires a lot of tillage. We used tremendous amounts of compost because at that point Earthworks was still in its early stages, heavily sup-ported by grants and the best place to put it was on our fields. So, we were raising our organic matter in six years from 2.5 to 3.7. It was great. But was there really an increase in structural fertility? Not as much as I hoped for.

What I also saw was a weed cycle where we initially encountered a lot of pigweed and lambsquarters, chickweed, galinsoga, and purslane came in. Tomor-row there will be a lot more about weeds, and weed control, but let me say a few things about this in relation to rotations and cover crops. When you leave the soil exposed and you work it too hard by breaking down its structural fertility, I believe, and this might be too flowery for you guys, that the soil is self corrective by wanting to cover itself up again. So, it is looking for the crop that will do this the quickest and most effective way. Well, chickweed and purslane are perfect in doing just that. The wisdom in the soil is looking for ways to cover up the mistakes that we make. As a result the crop rotation I will show you has incorporated grasses and legumes. Grasses and legumes are other crops that are very effective in covering the soil. They are able to, as was said before by Harold about nudity, put some clothes on that soil in a very effective way.

The other component about the following crop rotation is that it allows doing some very aggressive weed con-trol by introducing the bare fallow, which is possibly detrimental for some of the microorganisms and soil structure. The crop rotation serves the two purposes; increase structural fertility and providing control for diseases and weeds.

I just want to walk through some of these rotations with you. Here is one where we start the very first

year with oats and sweet clover. The reason why I use oats as a nurse crop is because the sweet clover germinates relatively slow and the oats is a good way to immediately help the soil, to anchor it so to speak. Later on after the oats is mowed down, the sweet clover will fill out.

The following year we spaded the sweet clover in to provide a wonderful nitrogen supply for my sweet corn. We over seed the sweet corn with red clover, with the following year the red clover being followed by a bare fallow. I incorporate the clover sometime in the summer when the ammonia, there is a tremendous amount of ammonia becoming available out of the red clover, is then easily being taken up by the soil and being converted to nitrates. That freely available nitrate then has to be anchored again by the oats and peas that are followed by potatoes. It is a challenge to get enough of nitrogen to my potatoes, while getting potassium is usually not a problem. It is available in the compost or I can spread Sul-Po-Mag (an OMRI approved potassium fertilizer). But getting enough nitrogen is difficult for both growing potatoes or corn and it needs clover incorporated in the rotation.

The potatoes are followed with an oats and peas crop. The potato crop serves almost as a bare fallow. There are hardly any weeds in the potatoes, first because a bare fallow preceded it, but also because the potato is very easy to cultivate since you keep hilling them. The oats and peas are chosen as winter cover crop because winter kills both, since we don’t want to do a lot of tillage, especially deep tillage, in the spring. When you do deep tillage you are going to bring more weed seeds up again, this is not a good idea, especially not after a bare fallow.

So, here we follow the oats and peas with onions. The onions come out of the ground sometime around the middle of August and are followed in September by rye and hairy vetch. The rye and hairy vetch are mowed down a few times and then incorporated to be followed by fall broccoli, or we (mow it once and) harvest the rye for straw. After the fall broccoli there is no cover crop. There is nothing to protect the ground over the winter and the ground is open. The good thing is that there is very little plant debris and we can follow with a fine seeded crop like early greens or spinach or lettuces. It can be anything as long as it is not a Brassica itself. Any rotation keeps families following each other with



the exception of the legumes and grains.

Now lets move ahead for a moment. We are going to show a few pictures.

Q: When do you apply compost?

A: Every time before a cash crop, ten tons of compost is applied in the spring. Right now we apply ten tons. I think that at a certain point, you should be able to bring that number down, but I agree with Brian that in the earlier years you really need to apply at least ten tons per acre. It is a lot of money, so you have to ask yourself if you can afford that. Another option would be to spread smaller amounts of compost, and supple-ment what you can’t get out of the compost from other sources, either through side dressing or any other way.

Q: How do you incorporate your cover crops?

A: We use a spading plow followed after flail mowing. The spading plow is the primary choice for incorpora-tion of large amounts of organic matter.

(Showing a slide of mature oats) Here the oats were not cut down and I will never do it again, I’ll show you why. This was a very dry year and the oats very much competed with the sweet clover it was a very poor stand so we are not taking that risk anymore. This was also kind of a dry soil to begin with, but you can see what a poor stand of sweet clover we have there (showing a slide of very small plants of sweet clover under a crop of oats). It was right before we combined it. At that point, I was greedy, I wanted to get the oats, and I wanted to get the grain. Right now, not having our cows anymore, there is no need for that. So, we mow the oats probably twice and then we mow it a third time (the clover).

This brings up another important thing; mowing your cover crops. Ted Blomgren did an interesting study us-ing an infiltrometer. I don’t know what it looks like but I understand the concept. It measures how much water the soil is able to take in. There were three plots – one plot with three years of cover crops, one with one year of cover crops and one year that was in vegetables. Guess which had the highest infiltration – it was the vegetable land. That wasn’t what I expected. Weren’t cover crops supposed to create those nice pores and structural fertility and everything else because that is

the idea? The more air, the more pores you have the quicker the water will actually infiltrate. We heard some remarkable numbers from Mary-Howell and Klaas Martens about their land. He was very much surprised. What I wonder about is that he was dealing with vegetable growers. Those people probably went out and cut their cover crops when they ran out of work everywhere else. Well, when do you think that happens? After it has rained a couple of inches. The priority was to get your cash crops in. When they ran out of all that work, they mowed down their cover crops and compacted their soil. So, it wasn’t a surprise at all, that the land that had been in cover crops for three years was extremely compacted. You have to look at your soil improvement crops as you treat your vegetable crops. Be careful using heavy tractors when mowing them down. You are driving a lot on there. We are mowing up to three times a year, which greatly helps in controlling weed populations, but you have to be careful. Those are heavy tractors, 7,000 pounds or more. I don’t know how many pounds per square inch are underneath the tractor tires, but it does add up.

(Showing a slide of red clover) This is actually not sweet clover it is red clover – we’ll come to it later in another rotation. This slide is taken around mid-summer. You see we are treating the field in one piece. Now we are dividing the field in sections. The whole farm is divided up into sections with a varying length but eight beds wide. Each section is divided and separated by a harvest lane. The eight beds in these sections, come close to being permanent. The tire tracks will fall in the same place, year after year, after year. The grass and clover strips in between are also permanent. It also allows for very good record keeping as far as rotation is concerned. The 70 acres that we operate, 30 acres at one time are in cash crops and the other 40 acres are in soil improvement crops. The way that we keep track of it is section by section. Here you can see that where one section is prepared for seeding. We spaded in the clover and then seeded down with oats and peas. That will be the following year in potatoes.

Here is the last cultivation of the sweet corn (showing a slide of young corn plants). After the last cultivation of the sweet corn, the red clover is over seeded. We do not wait a day, we have someone cultivating and hilling up the corn with another person walking behind with a cyclone seeder. It is one of those things you get



at Johnny’s Selected Seeds. It looks somewhat silly but it goes pretty fast. We are seeding our clover down at a rate of approximately 20 pounds to the acre. This is red clover. I tried sweet clover. It doesn’t handle the shade very well and it doesn’t handle the traffic very well either. (Showing a close up shot of sweet corn) You can see these are not weeds. The ground is clean at this point and you can see that the clover has germinated. You can see this is after harvest (showing corn stalks with a green cover on the ground). The corn has been harvested. The clover has established itself successfully. We then mow the corn down (showing the sweet corn mowed down)– you can see the stubbles there. It pretty much fills out. The rest of the rotation follows.

Pretty much this rotation is based on a system that was described earlier. Oats and barley over seeded with legumes is a very common practice at biodynamic or organic farms in Europe. I wondered how we could do this with vegetables. The last example I show you is one where we seed red clover at the beginning of the rotation – by the way if it is a seven-year rotation –At the end it will start the following year back at year one again. When you start red clover, you do not need a nurse crop like with sweet clover.

(Showing a slide of a tractor pulling a grain drill in a large field) Just as a note: we operate those 70 acres of land with 30 acres of in cash crops by myself, my part-ner Jody Bolluyt, four apprentices and two seasonal workers. That is close to 10 acres per person and we really don’t work hard. We like to work 40-45 hours a week. It is a matter of approach. A lot has to do with the fact that we put systems in place. The down side is that it takes a lot of land. But we have been able to cut down on the number of hours per cash crop per acre. We spend most of our time harvesting, which is key. We spend very little time on insect or pest or weed control. Weed control is something that takes five to ten hours a week for one person, besides the finely seeded crops that are being weeded by hand. Otherwise, we never touch potatoes, corn, cabbage, etc. by hand. It has to be a weedy piece of ground for us to hoe cabbage.

Another word on rye (showing a picture of rye and vetch in bloom). We grow quite a bit of rye and hairy vetch. If we want to harvest the rye, we do not mix in the hairy vetch. It really becomes a mess (trying

to cut it). Has anyone tried to cut rye and hairy vetch with a haybine before? I destroyed a haybine with it. It was an old haybine, I admit. But hairy vetch just clogs up the mower, which can be really awful. If you want to make your own rye straw, a sickle bar mower would be the best thing to use. We use a lot of rye straw as mulch.

This is garlic (showing a picture of a mulched field). We used a lot of mulch in between the black plastic. I will really shoot through these ones (slides) very fast because they are outdated. The reason why they are outdated is that our workers refused to work with straw. The allergies that people develop these days are inhibiting us from using large amounts of rye straw, so we still use it in our strawberries and garlic, but I had to find another solution for what to use in between the black plastic.

The solution that we came up with is living mulch. This is annual rye grass in between tomatoes (showing a slide of staked tomatoes with a living mulch). The three acres that we have in drip and black plastic is seeded down with Dutch white clover. This is one of those examples of a successful combination of a cash and cover crop in the same year. To establish the liv-ing mulch, you want to make sure you lay all of your plastic as early as you can to seed your Dutch white clover. Don’t wait as you may usually do and lay your plastic as you need it because if you wait until May and you seed your Dutch white clover the weeds will get ahead of you. I had a very interesting situation and if I had a couple more hours to talk I would talk about that more, but when we got the new farm we ended up with three different pieces of land. One was in rotation of potatoes and corn, the other one was continuous corn and the other one had been in a corn/alfalfa rotation, with four years alfalfa, and four years in corn. The one that was in corn and potatoes was heavily infested with purslane. I really did not know what to do with it. I seeded some Dutch white clover to see what would happen and to my great surprise it suppressed the purslane. When we laid black plastic in that field the Dutch white clover suppressed the purslane the whole season. It provided a beautiful cover. A note of cau-tion is to make sure you use Dutch white clover. We once seeded from a bag that said white clover on it. It was not white but red clover (which is an aggressive grower), it actually grows right over the plastic, and it starts invading your cash crop. Not a good idea. It



has to be Dutch white clover, not because it is Dutch, just because it is small.

Over seeding of red clover in winter squash (showing a slide of winter squash getting hoed) should be done at the last cultivation. Some people asked me earlier if you don’t have to rake the clover in. Again, I don’t think I have stressed enough you don’t have to as long as one person is following the cultivating tractor. The seeding happens within moments after the last culti-vation. The ground is nice and soft and it falls right in between those cracks. It germinates quite well. But if you wait, especially if you wait after a rainstorm to seed your white clover, it is not going to work very well. You are going to have to roll it in, rake it in, or do something. The incorporation of the clover seed happens by the ground being recently worked. This is actually a member’s workday here. We have members come up once a month helping us with hoeing and harvesting. We have 700 shareholders that support our farm.

Here you can see after the harvest (showing a slide of clover). You can see it is completely filled out. This is actually another slide right after harvest. Here you can see there are some patches that where underneath the plants that surprisingly well filled out. That was the last slide.

Questions

Q: When you over seed the clover to the previous crop do you find any disease problems with keeping that crop on the ground through the fall/next year?

A: In the case of winter squash there were a couple of reasons why I over seeded. Since we don’t like hand hoeing or hand weeding, winter squash is one of those crops where we always saw a few weeds going to seed. We have members hoeing there, and that is great be-cause they can get those weeds that the cultivator did not get. Normally speaking we would not have time for it and a few weeds would go to seed. The advantage of over seeding instead of disking in your winter squash crop residue, which some people said they do to pre-vent diseases in future years is the following. First, in this crop rotation the cucurbits do not come back there

for another five, six, or maybe even seven years so disease is not a problem. The problem with the winter squash is when we work in our weed seeds to establish a cover crop. These weed seeds that are buried can be a problem in future years. With over seeding the weed seeds, like lambsquarters or anything else that goes to seed, dies down, and we’ll mow it. The weed seeds lie on top. The birds will get it, smaller insects will get it, or it germinates the following year underneath the clover. It actually gives many advantages and does not create a lot of problems.

There are some problems though with having too many cover crops. There are some problems associated with cover crops as well. We have all this raw organic mat-ter, which provides this incredibly nice environment for some of the insects that we don’t like to see. We have problems with thrips because they come flying out of our grains after we cut them down and infest our onions. We really need to think about that. It might mean that we should always leave some grain standing up for them to go to instead of flying into the onions.

Q: Are the cover crops hosts for leafhoppers?

A: I find it mostly with alfalfa. I have not seen it with the clover. If clover is the host of that as well, we haven’t seen it, yet.

Q: Do you mow the clover?

A: The living mulch we do not mow, but if you have red clover, you do have to mow it. Again, we had red clover because of a mistake we made and we mowed it three or four times. We did not have a problem with tar-nished plant bug; we had a problem with leafhoppers. Again, I am assuming that they came out of the cover crops and came flying right in. I would say our big-gest problems with insects right now are flea beetles, cucumber beetles, thrips and leafhoppers. Colorado potato bugs are almost nonexistent. Why? I have no idea. I assume that some crops are serving as a host of their predator either over the winter or at other times.

Q: (Most of the question was inaudible) Something about nitrogen in compost, when do you cut back, will cover crops be enough? What are you thinking about in the long term?



A: Long term is to involve animals and then a lot of the fertility (from the soil improvement crops) will be exported from the fields in the form of feed. It means instead of cutting them down and plowing them in, you bring them to the barn and feed them to the animals over the winter. Bringing the composted manure back will mean we will import less compost from the outside. In other words, it will be a cycle within the farm.

Q: Will you cut back on the compost?

A: I think compost is very important. I don’t think a system within vegetables would ever work on cover crops alone. I think you eventually will lose important nutrients that are needed. I think the animals play an important role within the farm, and they will allow

you to import less compost. Maybe that is something that you want to aim for at one point, which is to im-port less compost. Lawrence B. Hill said, “Plowing under a cover crop is like a crocodile in a fish pond” – it is a lot of activity and then it is very quiet again. Soil life becomes very active and John said it earlier it is almost like applying liquid fertilizer. So, cover crops have their place for root formation, but maybe within the farm system as a whole system, there is more wisdom in feeding it to animals. Removing a lot of the above ground plant matter, feeding it to the cows, building a compost pile and then bringing that back in the form of compost seems to be a lot more sensible, while there is still a lot of that structural fertility being built by the plant roots. That would be the long-term picture.



To evaluate the fertility level of our soils, there are four different characteristics to distinguish.

1. Chemical fertility

a. Hayfields

Hayfields are generally self sufficient in nitrogen pro-vided there are plenty of legumes part of the hay mix. You might see your neighbors using generous amounts of nitrogen fertilizers on their hayfields, and in Hol-land, they practice this as an indirect weed-killer. The only plants that do well with an oversupply of nitrogen are the grasses. Grasses have a great ability to choke other plants given they are supplied with lots of water and nitrogen. High nitrogen levels also reduce the uptake of nitrogen by rhizomes that live in symbiosis with the legumes.

The best improvement in a hayfield is it to make it part of a rotational grazing system, in which cows are al-lowed for very short periods (1 to 3 days) to graze. In alternate years, the field is hayed with still allows for a fall grazing period. The most productive hayfields are usually the ones with the greatest number of species, considering the time an alfalfa field is out of production for reseeding purposes.

The annual potash requirement for the hayfields aver-ages around 80-110 lbs./acre. Roots and microorgan-ism can extract some potash out of the rock content of the soil or draw some it from the subsoil, provided the soil has no hardpan. An annual gift of 14 tons of cow manure provides 110 lbs. in potash.

The annual need for phosphate is around 25 lbs./acre. Three tons of manure would cover that need (based on average manure samples). Most manure contains rela-tive high amounts of phosphate caused by the grains fed to the animals.

b. Vegetables

All vegetables have different nutritional requirements. A rule of thumb is that:

• Most vegetables have relatively low needs for phosphorus.

• Leafy greens have higher than average needs for potassium.

• Most recent developed vegetable varieties do well with high levels of nitrogen.

• Most vegetables need a pH between six and seven.

Compost or manure releases only about 40% of its

Fertility Management at Roxbury FarmJean-Paul Courtens




nitrogen the first year with the remainder released in the following two to three years. When we spread the manure in the fall, losses of soluble nitrogen are high and we can only utilize 20% in the following year.

Nitrogen from cover crops, when plowed under, is released over a very short amount of time and care should be taken to avoid losses. Most of the nitrogen from cover crops consists of ammonia (highly volatile).

The nitrogen in manure consists for about half of am-monia and with the other half in nitrate, and in good compost, all ammonia is converted in nitrate.

A soil test will give some indication of where the state of your soil is. But besides giving accurate numbers for its pH and OM, It rarely allows for a good prediction of what the yields will be in an organic system. I have seen many instances where good soil health (good

Table 1Average Nutrient Absorption For Vegetables

Nutrients in lbs./acre

Vegetable Nitrogen Phosphate Potash

Asparagus 11 3 6Beans green 120 10 55 plants 50 6 45Beets 140 14 140Broccoli at 10,000 lbs. heads/acre 20 2 48 plants 145 8 160Brussels Sprouts 140 20 125 plants 96 9 110Carrots at 30,000 lbs. roots/acre 80 20 200 leaves 65 5 145Cantaloupe at 22,500 lbs./acre 95 19 120 Vines 63 8 35Celery at 100,000 lbs./acre 170 35 387 Roots 25 15 55Lettuce at 35,000 lbs./acre 95 12 170Pepper at 22,500 lbs./acre 45 6 50 Plants 95 6 90Spinach at 20,000 lbs./acre 100 12 100Sweet corn at 13,000 lbs./acre 55 8 30 Plants 100 12 75Potato at 40,000 lbs./acre 150 19 200 Vines 60 11 75Tomato at 60,000 lbs./acre 100 10 180 Vines 80 11 100

Adapted from Knott’s Handbook for vegetable growers

Average uptake from vegetables is:• 81 lbs./acre nitrogen (available in ±8 tons of compost)• 31 lbs./acre phosphate (available in ±4 tons of compost)• 122 lbs./acre potash (available in ±10 tons of compost)



structure, good biological diversity, and good physical qualities override its chemical contents.

The reality is that hay would do very well with an annual gift of 2 to 3 tons of cow manure to the acre, while vegetables need more than what the numbers from a chemical analysis suggest in order to produce a competitive yield. Vegetables do not support structural and biological fertility and their roots rarely extract minerals from the rock content of the soil.

2. Physical fertility

There are about 250 acres under Roxbury’s manage-ment.

What crop is growing on it is a direct result of the soil type we are working with. The presence of large rocks, steep slopes, or poor drainage makes some of this land unsuitable for vegetable crop production.

Good vegetable land has:

• A high carrying capacity (carry the weight of equipment without creating irreversible compac-tion)

• Good drainage

• Good access to irrigation water

• A deep A horizon (topsoil) that is free from stones

• Is almost flat with slopes that do not exceed 2%.

Table 2Different Compositions of Several Organic Fertilizers

All quantities in lbs./ton, except the first column

Type of Per animal in Dry Org.fertilizer lbs./180 days Matter Matter N P K Ca

Roxbury Farm Compost 924 327 12.5 8.25 12.6 20.3

Cow-dairySolid 13,000 430 280 11 7.6 8 8Urine 9,000 52 20 8 .4 16 .2Slurry 22,000 190 120 9 4 10 4

PigSolid 770 460 320 15 18 7 1.8Urine 990 40 10 13 1.8 9 1.2Slurry 1,760 160 126 14 9 8 1.5

ChickenSolid 44 640 460 25 37 18 47Slurry 88 220 160 16 13 10 22With bedding, 1,160 700 32 40 22 57(Free range)

Horse 620 500 10 6 11 6

Adapted from: Bemesting en Meststoffen by W.T. Rinsema PhD



• Is located in a long season micro climate

• Good exposure to sunlight

• Good air drainage to avoid late frosts.

• Good access to farm roads

At Roxbury Farm the 100 Acres that are suitable for vegetable crop production, only 30 are planted in cash crops each consecutive year. 40 acres are planted in soil improvement crops with the remaining 30 rented out to a neighbor for hay. Almost all of the vegetable land is rated category I or II (Occum, Unadilla, Knick-erbocker, and Hoosick). The remainder of the land is rated lower and divided between hayfields, pastures, woods, or wetlands. They are still important in provid-ing a broad biodiversity to the whole farm.

When we assess the physical quality of our soils, we determine its physical strength and limitations. Work-ing with land is not unlike working with a horse. First, we need to know what horse we are dealing with. Is it a workhorse or a riding horse? Each has different quali-ties. We will not try to pull a heavy load with a riding horse. Within this analogy, a sandy soil has qualities of a riding horse. Although it has its usefulness, we cannot get a lot of work out of it. It might pull a plow but it lacks the persistence of a workhorse to complete the task. Sandy soils, are great in the early spring since we have early access, since they drain well and warm up. But in the summer, they easily dry out, and can only achieve good yields with solid set drip irrigation. A workhorse on the other hand keeps moving, albeit at an initially slower pace, but with much greater resilience. A heavier soil, like a silt loam resembles a workhorse. They are a little later to warm up in the spring but their ability to hold nutrients and water gives them a great advantage over the summer months.

Nutrition is another analogy between horses and soils. Despite Too much compost to alter its physical charac-teristics, which results in excessive amounts of soluble minerals, creates high disease and weed pressure.

Starting off with a good soil is the best investment a vegetable grower can make. Altering the state of its soil is hardly ever cost effective.

3. Structural fertility

The way soil-particles are connected and organized in relation to each other reflects on its structural fertility. We evaluate how the soil particles are spaced and how many and how large the spaces are in between them. By the use of tillage tools and the compaction of tractors, the soil aggregates are broken. When the soil is worked too hard, it will not stand up to a heavy rainstorm and will collapse and erode. Soils with stable aggregates are more stable. Some soils do not have the physical characteristics to create stable aggregates. In that case, the only remedy is adding organic matter.

A stable structure will have:

• An equal distribution between mineral particles and pores.

• Good ability for roots to penetrate.

• Good ability to hold water.

• Good ability to drain excessive water.

Hay fields and pastures are in general self sufficient in creating good soil structure. Their root system supports many microorganisms that feed directly on plant matter or live off the conditions created by the roots during growth as well as decay. In general, most grasses create a surplus of carbonaceous materials, and the organic matter content of the soil increases. This will help connect the soil particles into stable aggregates. Microorganisms feed on the decaying organic matter and together with the extensive root system of the grasses help the way in which the soil particles are ordered. They leave many pores, which will provide drainage and capillary action in times of drought. Vegetable crop production, by its nature of exposing the soil and introducing equipment, do not maintain soil structure. Besides this, most vegetable crops do not have very well developed root systems unlike most grasses.

Strategies to support good structure are:

• Supply high amounts of organic matter that contain humus formative particles.



• Add Calcium as building block for clay soils.

• Avoid breaking up the soil beyond natural breaking points

• Increased root activity by using soil improvement crops.

• Increased root activity by using Biodynamic prepa-ration 500.

• Frost as an action to fracture compacted soil.

To help determine how we treat the soil during the season tillage tool should not fracture the soil more than when we drop a clump of soil from a height of three feet. Ideal is to use tillage equipment that has an action similar to that of a hand-fork. A hand fork fractures the soil at its own breaking points. A spade and damages the aggregates where it slices the soil. The coloration at the back of the spade is an indication of smeared soil particles. The aggregates that order the soil have come apart.

Three different purposes of tillage:

• Aeration of the soil. (Depth anywhere between 8 and 18 inches)

• Incorporation of organic material. (How deep do you want to put your organic material?)

• Creating a seed or plant-bed. (How smooth and level does this have to be?)

Conventional equipment rarely combines all three tasks. Only a spading plow with secondary attachment will accomplish this and it will aerate at the same depth as it puts the organic materials.

For primary tillage, a Chisel plow is used to aerate the soil. In order to incorporate cover crops with this tool the use of a shredder or flail-mower is necessary. The chisel plow does not turn the soil and leaves a lot of plant matter on the surface. After the primary tillage, a Perfecta II Cultivator is used to smooth out the field. This tool consists of a combination of sev-eral “S” tines, a leveling bar, and a set of crumbling rollers. It leaves the soil level and smooth enough to plant: cover crops, Cole crops, potatoes, squash, and even lettuce-plugs. For crops that have small seeds and

that require extremely level ground with no clumps or stones on the surface a Buckeye bed former is used. This tool leaves a trench every 72 inches, creating a soil surface that resembles raised beds. The planting surface of the bed is 54 inches wide and allows for three rows 18 inches apart. The trenches have proven to be very successful in allowing the crops to stay dry much longer during periods of heavy rain. The combination of better drainage and the level plant bed prevents bottom rot and creates conditions for successful mechanical weed control.

4. Biological fertility

Here we recognize three areas of importance:

• The cycles in nature, that includes decay and de-composition of organic matter.

• The creation and maintenance of soils.

• The nutritional value of cultivated plants.

At Roxbury Farm this is addressed with the following measures.

A. Applying compost and incorporating soil improvement crops increases soil fertility

Fresh organic matter, is important to add to the soil because:

• It feeds the microorganism.

• It keeps the nutrients in a cycle.

• It creates a better structure of the soil by acting like glue to the soil particles (Fungi).

Ultimately a good soil transforms this organic matter into…

Humus

Humus, the most stable form of organic matter that:

• Has the ability to absorb both nutrients and wa-ter. Humus compared to clay can hold up to four times as much water, and the nutrients in humus



are available to plants but cannot be washed out by excessive rainfall.

• It increases the structure of the soil.

Compost

Roxbury Farm works closely with the company Earth-works. This company was formed with the help of the state of New York to research the possibility of keeping organic materials out of the landfill. Earthworks col-lects produce from supermarkets, horse bedding from farms, and pulp from canneries. These materials are mixed with a Sandburger compost turner and carefully monitored for temperature and moisture. This machine is also utilized to make compost from cow manure to be used at Roxbury Farm.

Theprocessofmakingcompostatabiodynamicfarm

During the winter, the cows are usually kept in a free stall setup. In this method, the hay is fed in the form of round bales inside the stall and placed on top of the packed manure. The cows are kept off the manure by applying bedding on a regular basis. This can consist of old hay, straw, and or wood chips. If an adequate source is available, rock dust, like Basalt meal can be added to the manure pack. After six months, the packed materials are about three feet deep. In May, the manure is removed with a bucket loader. The pile is build with a manure spreader, with its final shape created by the turner. The biodynamic preparations are inserted into the pile by pushing a long stick two feet into the pile. Only small amounts are needed in each hole to prepare a pile.

A variety of materials in a manure-pile allows it to be mostly self-sufficient in the process of transformation. A pile that has a variety of materials in it develops a combination of aerobic and semi-anaerobic bacteria. The piles heat up 120° to 160° Fahrenheit and stay at that point for quite a few weeks. A specially designed cover is placed over the piles to shed of any excessive rain and to keep the moisture in. The cover functions like a skin. It protects the pile from the elements with-out restricting it from breathing. A pile behaves like any other organism on the farm: it breathes, consists mostly of water, and has body warmth, except it will not break any fences. The piles are turned when nec-essary, and water can be added. The whole process of

composting takes about 6 to 12 weeks. The compost, when applied is not finished, but will have lost most of its odor. The ideal time of application is on a cloudy day with plenty of rain in the forecast. After applica-tion, the ground is chiseled or spaded. Manure handling can be the weakest link in the farm’s fertility cycle. At a biodynamic farm, it is important to keep nutrient losses as low as possible.

Fibers play an important role in the composting pro-cess. Most fibers are “used up” at the end of the com-posting process. Hay and straw are good examples of being good energy providers for the microorganism. Their presence is vital in the process, but it is impor-tant to include materials that contain lignin. They take a longer time to break down, and this kind of carbon compound is not readily available as an energy source for the microorganism. But at the end of the compost-ing process, they contribute to the formation of humus at a much higher rate than fibers do. All carbonaceous materials have a different ability to become humus. The materials with high lignin fractions, like peat moss, sawdust, and leaves have what we call a high humification coefficient. They alone cannot provide the microorganism with enough energy to start the decomposition and hay, straw, or green material has to be added to the pile to jump-start the process. The manure contributes nitrogen and other building blocks that are used by the microorganism to grow and mul-tiply. By adding soil or rock dust to the manure, we create conditions that can occur only under ideal cir-cumstances in very good soil. The humus can transform into a clay-humus complex. This aggregate represents the most stable soil component, which has a very high capacity to hold nutrients and water.

The eventual goal in applying good compost to the land is to increase the overall health of the soil. Compost is also very effective in raising the Organic Matter level of our soils

B. Soil improvement and cover crops

Thebenefitsofcovercropsandsoilimprovementcrops

Reduction of soil erosion. A crop of rye seeded in Sep-tember and plowed under in April is able to keep the soil from eroding away over the winter months. Rye and hairy vetch as a mix are very effective. And will add to soil-life, though the humification coefficient can



be very low, soil life is greatly benefited by the mere fact that the ground is not left exposed. The roots of the cover crops after breakdown form the very important capillaries for drainage as well as water uptake.

Increase of pores in soils and breaking up hard pans. Sweet clover is known for its deep penetration of the soil and breaking of hard pans. But any established grass will greatly increase the amount of pores in the soil.

Increase in microbial activity. Soil particles are held together by microbial activity especially the group of fungi. Without activity of roots providing microorgan-ism the needed air, and carbon for their activity very little microbial action would exist.

Increase in organic matter content through carbon intake. Grasses are known for their excellent ability to fix carbon out of the air. For greatest uptake of carbon in one season, Japanese millet and sorghum-Sudan are favorites.

Fixation of Nitrogen through rhizomes living in sym-biosis with legumes.

Weed management. Many crops are able to choke out other weeds, and by frequently mowing of our cover crops, we reduce the number of weeds going to seed.

Plant disease management. Most cover crops do not host plant diseases known in cash crops

Overall farm diversity. Most insects feed off the pollen of the grains and grasses. In some instances, the cash crop acts as a beneficial host. The pollen of the sweet corn is a good example. For that reason, parsnips can be left in the ground to flower in the spring. The flowers that are formed in the following spring provide a habitat for the trichogramma wasp. Dill, which is another Umbelliferea, serves the same function. After the dill is cut, the plants remain alive and produce flowers at a time when the parsnips have gone to seed.

The roots of the legumes live in symbiosis with mi-croorganism called rhizomes. Look at the roots of the legume to find out if nitrogen is in the process of being fixed: if the roots have nodules that are red or pink colored inside, it has active rhizomes. If the roots do not show nodules, find out if the soil pH is too low or

if the particular rhizome is in your soil. Many legumes live in symbiosis with different rhizomes.

Disadvantagesofcovercrops

Sod can provide a cover for the eggs of many in-sects. Flea beetle and carrot-fly take advantage of this environment. Grains and Alfalfa hosts thrips and leafhoppers. Once the grain is combined or the alfalfa cut, the many insects including thrips and leafhoppers look for a new home. As we increased our acreage in grains and legumes so have our problems with thrips and leafhoppers increased. One solution is to have another crop available (besides the vegetables) for the insects to migrate to and to never mow all the cover crops at once.

Another detriment from too much raw organic mate-rial is the residual activity in the soil that can manifest itself like fresh manure. Many diseases and pests like aphids’ increase when too much raw fertility is applied. Lawrence D. Hills of the Henry Doubleday Soil As-sociation, once said: “Plowing under cover crops is not unlike throwing a few fish in a pond filled with croco-diles.” Crocodiles are a beautiful metaphor of soil life.

WhatweseedindifferentmonthsinNewYork

April and May

• Oats with red or sweet Clover

• Rye with Dutch white clover on head lands (the Rye will not form a seed head)

• Dutch white clover in between plastic

May and June

• Buckwheat after spinach or other early crop

• Sweet clover, red clover over seeded in the sweet corn and Winter squash.

July

• Japanese Millet or Sorghum-Sudan with Hairy Vetch mixed in.



organic matter in tons/acre

68

Cropland

Total Organic Matter

64

60

10

54

50

56

SodCropland

Time in Years

5 10 15 20 25 5

Figure 1

Grass-clover1 year 2250 1350 3600 10502 years 6000 1350 7350 23003 years 9500 1350 10850 3600

Alfalfa1 year 1800 900 2700 7002 years 2700 1350 4050 12003 years 4500 1350 5850 1850

10 tons of compost 6540 6000

Table 3Amounts of Organic Matter of Different Crops Remaining after Harvest in Same Year and Following

All numbers in lbs./acre

Remains after Under Above oneCrop ground ground Total year

All numbers in lbs./acre

Remains after Under Above oneCrop ground ground Total year

Rye 1100 3300 4400 1350Oats 1250 3300 4550 1400Potatoes 450 3150 3600 750Beets 450 300 750 250

Cabbage 900 3600 4500 1000Peas 350 1400 1750 400Beans 350 1400 1750 400Onions 270 180 450 130

Adapted from: Bemesting en meststoffen, by W.T. Rinsema PhD



August

• Oats and Peas

September

• Rye with Hairy Vetch, Oats and peas.

October and November

• Rye

C. Crop rotation

Within the vegetable land have a system of permanent sections, that each contain eight beds. Permanent sec-tions allow for keeping records of where the crops have grown and aid in exact planning. There is no guesswork in finding where last years crop was planted. The harvest lanes also serve as a means to get easily to the cash crops, a place to pull in the irrigation reel, and as pasture for the bees (since they mostly contain white clover).

Crop rotation is a tool used to break insect, weed, and disease pressure in the vegetable fields. There are many reports of increased yields of cash crops in fields that adopt rotations. In organic agriculture, we should not only rotate within the plant families of our cash crops but also include grasses and legumes in our rotation mix. As seen in the graph above, they fix decent amounts of organic matter and introduce a broad spectrum of soil life to the farm. They can also form a habitat for beneficial insects. They are a neutral crop in our rotation since they rarely host diseases that affect our cash crops. Proper incorporation and time to let the soil digest the plant matter is important. Too much raw organic matter can greatly affect the health of our cash crops in a negative way. Introduction of bare fallow periods in “neutral” years are effective in breaking up both weed cycles and incorporation of large amounts of plant matter.

At Roxbury the different plant families are:

• Apiaceae or Umbelliferae: carrots, parsnips, pars-ley, celery, dill, etc.

• Asteraceae or Compositae: all the lettuces, esca-role, and certain cut flowers.

• Brassicaceae: all the Cole crops including broccoli, arugula, turnips, etc.

• Chenopodiaceae: all beets, chard, and spinach.

• Convolvulaceae: sweet potatoes

• Cucurbiticeae: all cucumbers, melons, squashes etc.

• Fabaceae or legumes: peas and beans.

• Liliaceae or Alliums: all the members of the onion family

• Poaceae: all grains including sweet corn.

• Rosaceae: strawberries

• Solanaceae: all nightshades, including eggplant, peppers, tomatoes, etc.

A few vegetables, herbs, or cut flowers are adopted in another family because they are relatively insignificant. A rule of thumb in any crop rotation is that no family follows itself in less than four years. Another guideline to use is to have plants with opposite nutrient require-ments followed each other. And lastly crops that see this pressure more in the spring or fall alternate crops that show great weed pressure in the summer. This is done to offset the cycle in which those plants go to seed.

Use table 4 (page 54) as an example.

D. Mulches

Introduction of living mulches have become an im-portant tool at Roxbury Farm to help create a good environment for our cash crops. The use of Dutch white clover in between the plastic has reduced Al-ternaria infections in tomatoes and keeps fruit clean in peppers, eggplant, cucumbers, melons, and squash. Over seeding of red clover in sweet corn and winter squash allowed for nitrogen fixing for next year’s crop. We used to apply a lot of dead mulch like straw and leaves, but the dust and discomfort to our workers have limited the use of this to Strawberries and Garlic. As an alternative to straw, the beds with garlic can be covered with about six inches of leaves. Six inches is



a sufficient amount if you do not like to weed at all the following year. The garlic pops right through in the spring so this system works quite well if perennial weeds are not a problem.

E. Biodynamic preparations and compost teas

The use of Biodynamic preparation in the compost increases its ability to suppress plant diseases and introduce microorganisms needed for proper plant growth. Preparation 500 has shown to increase rooting depth of both cash and cover crops.

Research done by Elaine Ingham of the Soil Web has determined what microorganism help plants grow. She

classified over 50,000 microorganisms in particular crops. After she tests a soil sample, she prescribes particular teas to inoculate the soil with the missing microorganism to provide for proper plant growth.

Within the management practices of the biodynamic preparations, we can distinguish between two different kinds of applications.

1.Thecompostpreparations

The central thought behind the compost preparations is to give the compost a memory. When you make compost, the original material will transform into something completely new. Even chemical analysis cannot determine what the original material consisted

Table 4Crop rotation

Year 1

Greens

Bare Fallow

Oats andPeas

Year 2

Carrots

Year 3

Winter-Squash

Red clover

Year 4

Red Clover

Bare fallow

Oats andPeas

Year 5

Potatoes

Rye andHairy Vetch

Year 6

Rye andHairy Vetch

Bare Fallow

Oats

Year 7

Peas andBeans

Oats andPeas

Year 1

Red Clover

Year 2

Red Clover

Bare Fallow

Oats andPeas

Year 3

EarlyBroccoli /Cabbage

Rye andHairy Vetch

Year 4

Rye andHairy Vetch

Bare Fallow

Oats andPeas

Year 5

Strawberries

Year 6

Strawberries

Bare fallow

Oats andPeas

Year 7

Spinach

Lettuce

Year 1

Oats withSweetClover

Year 2

Sweet clover

Sweet-corn

Red Clover

Year 3

Red Clover

Bare Fallow

Oats andpeas

Year 4

Potatoes

Oats andPeas

Year 5

Onions

Rye andhairy Vetch

Year 6

Rye andHairy Vetch

Fall Broccoli

Year 7

Greens

Lettuce



of provided the original materials were of organic ori-gin and the process of composting was done correctly. The word organic does include all compounds that are of organic origin, including chemicals.

There are six different compost preparations:

The oak bark preparation is made of finely ground-up oak bark that is put inside the skull of a freshly slaughtered cow. Great care is taken when the brains are removed to make place for the oak bark. Some people use a garden hose to flush out the brains but most likely, even though it appears to be gentle, it has the effect of flushing the essential membrane out as well. The membrane should be left intact, since the working of this membrane has the desired influence on the transformation of the oak bark. The skull is then placed in water that is preferably mucky and moving. This preparation will, if made properly, give the capac-ity to the compost to make the plants, grown on the composted soils, resistant to disease.

The chamomile preparation is made of dried chamo-mile flowers that are briefly soaked in lukewarm chamomile tea. This substance is then placed in freshly obtained intestines of a cow. Again, we see people clean these intestines out a lot with water, but we rec-ommend leaving them the way they are to avoid dam-age. An intestine free from grass is ideal, but avoid any intestine from a cow that was grain-fed. The stuffed, so-called sausages are then placed in the soil and kept there over the winter. Great care is taken in what loca-tion the preparations are buried. The ideal location is where snow usually accumulates. The intestines will help the chamomile transform into a substance that will give the compost the ability to work in the processes in which potash and calcium are involved. The manure treated with the chamomile preparation shows greater stability of its nitrogen content.

The yarrow preparation is made with dried yarrow flowers that are briefly soaked in lukewarm yarrow tea. This substance is placed in the bladder of a stag that is enlarged by simply having it blown up like a balloon. This little bag is hung up on the south side of the barn during the summer months. In the fall it is buried the same as the chamomile preparation. The yarrow preparation gives the treated manure the ability to work in the soil in such a way so that it is capable of adsorbing minute quantities of trace minerals.

The nettle preparation is the easiest to make and can be used as a foliar spray. The nettle is harvested before the flowers go to seed. It is then directly placed in the earth, but not in direct contact with it. We place a layer of peat moss between the nettle and the moist earth. It is left there for a full season (summer and winter), and is then dug up and used as a preparation in the compost pile. Nettle does not need an animal organ. The nettle preparation has a strong relationship to the iron processes in the plant.

The dandelion preparation is made from the dried dandelion flowers. The flowers are picked in the morn-ing. Only the flowers that have not yet fully opened are useful. When they are dried, mature flowers become seed. When we make this preparation in the fall, we start by soaking the flowers in lukewarm dandelion tea. The next step is to place this substance in little bags that we form out of the mesentery of a cow. The mesentery should be free of fat since that would inhibit proper transformation once it is placed in the soil. Also, when the bags are too large, there is a chance that the substance will turn into silage. A good size is about the amount of a baseball. These pockets are then buried like chamomile. The dandelion preparation is working through the compost in giving wisdom to the soil. All the positive influences from stream, pond, forest, meadow, and fields become available to the plant through the composted soil, giving the plant the faculty to attract these influences.

The last is the valerian preparation. Here the flowers are collected and the juice is pressed out. We are not blessed with having any significant amount of it grown around us, so I do not have any personal experience with making this one. But I can describe how to make it. First, make sure you have the real Valeriana offi-cinalis. I have seen people using plants that look just like the valerian, but if it is not the real thing, it will not do what we are expecting. What you are after is the juice of the flowers. You can use a press to squeeze the juice out of the flowers. There are two variations available: one is fermented, which I prefer, and the other is bottled up the way it comes out of the press. The smell of the fermented valerian is wonderful. This preparation is made without an animal compo-nent like the nettle. The finished tincture is diluted in lukewarm water, stirred vigorously, and sprayed onto the compost pile. The valerian acts like a skin and contributes an element of warmth to the pile. In the spring, I take advantage of this ability by spraying the



valerian tincture on tender plants to protect them from early morning frost.

2.Thefieldsprays

The horn-manure and horn-silica preparations are both made with the horn of a cow. The horn of the bull is too soft. This is an interesting phenomena, which must fluster the Darwinist.

In the fall, we make the Horn-Manure preparation. The manure from a lactating cow is selected. The manure should have enough form so that the shape of the intestines is somewhat visible. But avoid using pies that start looking like sheep-manure. We place the manure into the horns and then bury them with the points of the horns sticking up to avoid rainwater from collecting in them. In the month of May, this preparation is dug up. The substance in the horns has by then become odorless. If there is a smell to it or if it still looks like manure, then you know that it has not been properly transformed. Before this preparation is applied to the fields as a spray, we have to dilute it in lukewarm water. About a baseball, size quantity per thirty gallons of water is sufficient. This is stirred vigorously in one direction until a vortex is formed, then the direction is reversed and stirred in the oppo-site direction to create another vortex, etc. The total time of stirring is one hour. The solution will now start smelling again, not like manure, but definitely alive. For filtering the liquid I found paint bags to be the best, the ones painters use to filter their paint. We do the filtering to avoid wasting time in the field cleaning spray-nozzles. Our Solo backpack sprayer covers about one acre if filled up. This is about three to three and a half gallons. This preparation is sprayed

directly on the soil. If the soil has been worked, it can readily adsorb the positive influences of this prepara-tion. Horn manure directly influences the way organic matter is transformed in the soil. Its positive influences are similar to what organic matter does to the soil. In general, we notice that horn manure works on germi-nation, root development, and growth.

The Horn-Silica preparation makes use of a cow-horn again and finely ground Silica. This is then placed in the ground during the summer months. A much smaller quantity than the horn manure, no more than a pea-size amount, is stirred vigorously in 30 gallons of water for one hour. This solution is sprayed directly on the plants. The Horn Silica has a strong connection to the light and warmth forces of the summer. Its positive influences are similar to what the summer sun contrib-utes to the plants. It slows down growth but increases the overall plant mass. Plants treated with this prepa-ration will have better taste and keeping qualities. All preparations with the exception of Horn-Silica should be stored in peat moss, in a dark, cool, and damp place. Horn-Silica is left in a glass jar in a windowsill.

A study published in “the Journal for Science” com-pared organic, biodynamic and conventional research plots and found that the number and diversity on the biodynamic plots were far greater that the organic ones. This research that was conducted over a 21-year period showed that the biodynamic preparations greatly improve soil life. Another study performed by the University in Washington compared organic and biodynamic pastures in New Zealand. This study fo-cused mostly on soil structure and rooting depth. The biodynamic plots had greater root systems and better soil structure.


Weed Management



Weed Management 59

What is a weed?

Weeds are commonly defined as plants that grow where they are not wanted. Although that definition has some practical utility, it fails to recognize that weeds share certain properties in common. Only a handful of the species you see around show up in farm fields and other places that you don’t want them. Understanding what makes certain plants grow in human manipulated sites whereas others do not is a first step in planning management programs. From an ecological point of view “weeds are plants that are especially successful at colonizing disturbed, but potentially productive, sites, and at maintaining their abundance under conditions of repeated disturbance” (Mohler 2001).

Our crops are mostly annual species. That is, they com-plete their lifespan in less than one year. To make the habitat suitable for annuals, we eliminate the natural vegetation, which around here is broadleaf forest with a little hemlock and white pine. Annuals do not grow in forest conditions or in undisturbed prairie either, because little seedlings cannot compete with large, well-established plants that already occupy the site. So to make the land suitable for annuals, we clear off the woody plants, and plow up the soil to disrupt the perennial herbs. In ecological terms, plowed fields are perpetually held at year 0 of ecological succession. In other words, farming creates habitat that is suitable

for species that specialize on highly and repeatedly disturbed conditions, namely weeds as defined above.

The basic thesis of this paper is that understanding the biology of weeds is a key to their control. The reason is that killing weeds without harming the crop depends on biological differences between the weeds and the crop. Weed biology becomes complicated, however, because weeds differ in their biology: there are many ways to be a weed. Fortunately, the variety of weeds can be grouped into a few categories based on the life-history of the species. That is, for manage-ment purposes, weeds can be grouped according to how long various life stages live, and how the plant reproduces. At the broadest scale, weeds can be di-vided into annuals and perennials, and I will begin with the perennials.

Perennial weeds

Types of perennials

A perennial weed is a weed that persists in the vegeta-tive state for more that one year. The types of perennials can be classified according to whether they reproduce vegetatively, and the nature of the perennating organ (Table 1, page 60).

Understanding Weed BiologyCharles L. Mohler

Senior Research Associate Crop and Soil Sciences

Cornell University



Stationary perennials do not reproduce vegetatively, except occasionally when the taproot or root crown is broken by a tillage implement. Most reproduction is by seed, and they commonly produce copious quanti-ties of seeds that typically persist in the soil for many decades. Primarily, they are weeds of pastures, hay meadows and waste ground. When the soil is regu-larly tilled, they tend to disappear after a year or two, except for species like dandelion that regularly blow in from adjacent habitats. The reason for the absence of stationary perennials on tilled ground is two-fold. First, since the root system is not well built for vegeta-tive propagation, soil disturbance tends to damage the storage organs and kill the plants. Second, stationary perennials are usually not very competitive the first year because they are putting energy into building the taproot or the root crown so that they will have the resources to survive the winter. They are often highly competitive in subsequent years, however, because they have these substantial reserves with which to rapidly establish in the spring and compete with any annuals present. These qualities explain both why they are usually minimal problems in organic annual agri-culture, and why they can reach substantial abundance in pastures, hayfields, and conventional no-till fields.

Wandering perennials reproduce primarily by veg-etative reproduction. They spread underground by thickened storage roots or by horizontal underground stems (rhizomes). A few species also produce bulbs or tubers that are the overwintering storage organ for the plant. Although many of the wandering perenni-als do produce seeds under some conditions, typically seed production is low, and the seeds usually do not persist long in the soil. Most of these species do not self-pollinate (Mulligan and Findlay 1970), and conse-

quently, if the population consists of a single clone, no seed production is possible. For example, only about one yellow nutsedge population in 10 produces viable seeds (Mulligan and Junkins 1976). For wandering perennials, seed production is mainly a way to spread the species around rather than a way of maintaining the population at a particular site. For that, the plant relies on sprouts from the root or rhizome system.

Below-ground apical dominance in perennial weeds

The key fact about the underground organs of perennial weeds is that they show what botanists refer to as apical dominance (Håkansson 1982). You are familiar with this phenomenon in the above ground shoots of plants: if you prune off the end of a branch, the nearest lateral bud (or buds if the leaves are opposite) will begin to elongate much sooner than they would otherwise. This occurs because the growing point of the branch produces hormones (auxins) that suppress the growth of the lateral buds. When the growing point is gone, so is the suppression and the lateral buds grow. They then produce auxins that suppress the growth of buds further down the stem.

Essentially the same phenomenon occurs in the root or rhizome system of wandering perennials (Figure 1). The above ground shoots emerge from the terminal bud of the rhizome or storage root. If this shoot is removed, then the next bud in line is released and a new shoot grows up to take the place of the one that was killed. More critically, if the root or rhizome is broken into pieces by a tillage implement, then the terminal bud on each piece will be released from suppression, and you will see lots of sprouts. Each of these sprouts will

Table 1Types of perennial weeds and examples.

Nature of the root system ExamplesStationary perennials

Taprooted Dandelion, burdockFibrous rooted Broadleaf plantain, tall buttercup

Wandering perennialsBulb or tuber Yellow nutsedge, wild garlicShallow storage organ Quackgrass, johnsongrassDeep storage organ Common bindweed, Canada thistle


Weed Management 61

be relatively weak, however, because it is backed up by small reserves of carbohydrate.

From a management perspective, this behavioral re-sponse of wandering perennials is either good or bad depending on what you do. If you till up a stand of quackgrass and then plant onions, you probably will have worsened your weed problems. In contrast, if the field is tilled, the fragments allowed to sprout, and then you cultivate out the sprouts, you will have seriously depleted the already weakened rhizome fragments. Repeating this process, or planting a fast growing, highly competitive crop will further suppress the weed (Håkansson 1971). Since quackgrass is a cool season grass, sowing a fall cover crop of rye or winter wheat at a high density is pretty effective. Note here that any one of the several measures taken alone would probably be insufficient to control the weed. Just fragmenting the rhizomes with tillage would likely increase quack-

grass density; cultivation without using a prior tillage practice that severely fragmented the weed would just spread the infestation around. Competitive crops are always helpful, but rarely sufficient to control peren-nial weeds unless the weeds have previously been set back by tillage and cultivation.

Not all wandering perennial weeds sprout immediately after fragmentation, but that is the usual pattern, and most of the wandering perennials in the Northeast be-have in this way. Some species, notably the common and hedge bindweed and Canada thistle are not easily broken up by tillage because their root or rhizome sys-tems are so deep in the soil. To get at hedge bindweed or Canada thistle requires subsoiling equipment, and on a deep soil, much of the root system of common bindweed will be completely out of reach. The only alternative then is to try to exhaust the whole mass of the root or rhizome system by repeated killing of the

Figure 1Due to hormonal suppression of most buds by the terminal shoot (apical dominance), breakage of rhizomes or perennating roots results in an increase in the number of shoots, but a decrease in the resources available to each.



emerged shoots. For many wandering perennials, the shoot begins transporting food back to the root system at about the 3 to 4 leaf stage, so that is a good time to cultivate. Before that, the shoot is a net drain on the perennating storage organs.

Weed seeds

Germination cues

Annual species are plants in which the individual lives for less than one year. These species necessarily reproduce by seeds. Because reproduction by seeds is essential for annuals and they live in a frequently disturbed environment, they produce many small seeds. They have been selected to produce many seeds so as to spread the risk of death by disturbance over many offspring. Most weeds die young so they make a lot of seeds to compensate for that mortality. Since each individual plant has limited resources, producing many seeds necessarily means that the seeds are small. I will return to the consequences of small seed size repeatedly. Another way in which annuals manage the riskiness of specialization on disturbed environments is by recognizing the most favorable conditions for germination.

Since most weed species have small seeds, most weed seedlings lack the resources to be able to grow up from deep in the soil and most emergence is from seeds near the soil surface (Chancellor 1964, Mohler 1993). Nearly all individuals of small seeded weeds (and most weeds in the northeastern U.S.A. weigh less than 2 mg), emerge from within the top inch of soil (Figure 2, lambsquarters, redroot pigweed). Even relatively large seeded weeds like velvetleaf (9.5 mg) mostly emerge from within the top 2 inches of soil (Figure 2). Since seeds that germinate deep in the soil die, weed seeds that recognize when they are near the soil surface have been favored by natural selection.

Since most weeds have small seeds, they make tiny seedlings. A lambsquarters seedling when it first comes up has cotyledons that are about 1/32 of an inch wide and 1/8 inch long. Such tiny plants have no chance of survival in established perennial vegetation like a hay meadow or forest. Consequently, most weeds have been selected for physiological mechanisms that allow the seeds to recognize that competing vegetation is

limited or absent. In natural conditions, the main thing that eliminates perennial vegetation is soil disturbance, usually by animal activity. So some of the signals that cue germination are related to soil disturbance, whereas others are simply related to the absence of vegetation or near surface conditions. Few of the cues are absolute requirements for any species. Rather, they change the percentage of seeds that germinate and work together to signal the appropriate conditions for germination. No species responds to all of the cues discussed below, but most respond to several.

The most common cue that weeds respond to is light. Most weed species show increased percentage germi-nation in light relative to darkness (Table 2, page 64). Some species, like common chickweed, germinate in the dark when first shed from the plant, but after burial in soil, show greatly increased germination if exposed to light (Wesson and Waring 1969). The amount of light required to stimulate germination is sometimes amazingly small. For example, redroot pigweed will germinate in response to a few thousandths of a second of sunlight (Gallagher and Cardina 1998). Thus, if a seed comes to the surface during tillage or cultivation and then is buried again it may be stimulated to ger-minate. This is why tillage in the dark often reduces the density of weed seedlings (Ascard 1994, Scopel et al 1994, Buhler 1997). Dark tillage is no panacea, however, since weeds respond to other cues as well.

Even the type of light affects germination. Red light stimulates germination. Light filtered through a plant canopy is green; which is to say, it is depleted in the red wavelengths. Thus, if a light sensitive seed is exposed to green light, the seed senses that it is surrounded by competing vegetation, and germination is inhibited (Górski 1975, King 1975). Seeds behave oppositely to cars: they stop on green and go on red, and ordinary sunlight is full of red wavelengths.

Another factor that stimulates germination of some weed species is high soil temperature. For example, redroot pigweed germinates best at 86° to 104° F (Table 3, page 64). Soil temperatures that high are rarely achieved except near the surface of bare soil. Common purslane germinates best at similarly high temperatures (Vengris et al. 1972).

When soil is bare, the high temperatures obtained during the day are often not retained during the night because the soil cools by emitting infrared radiation to


Weed Management 63

Figure 2Proportion of seeds planted at a given depth that emerged as seedlings for three common weed speciesSeeds were cold treated at 40° F in field soil for approximately two months and then placed at the indicated depth in early spring without exposure to light.(RedrawnfromMohler,inpreparation)



the sky. Consequently, surface soil temperature fluc-tuates much more for bare soil than for soil covered by living or dead plants (Teasdale and Mohler 1993). Many weed species use this temperature fluctuation as a means for recognizing bare ground (Table 4). For curlydock, temperature fluctuation is nearly an absolute requirement (Totterdell and Roberts 1980). Provided the seeds are exposed to light, percentage germination at any constant temperature from 35° to 95° F is near 0 but a variety of different fluctuating temperature regimens give 100% germination.

Weed seeds also germinate in response to chemical cues associated with soil disturbances like tillage. Aeration and warming of the soil by tillage stimulates microbial decomposition of soil organic matter. This releases nitrogenous compounds that specialized bacteria turn into nitrate. Nitrate in the soil solution stimulates germination of some weed species, like lambsquarters (Roberts and Benjamin 1979). In addi-tion to the problems chemical fertilizers create for the soil, this is another good reason to avoid them.

When diffusion of gasses is limited, for example, deep in the soil or in the interior of soil aggregates, oxygen may limit the respiration of seeds. Seeds are alive, and moist seeds are particularly active metabolically. When oxygen is limited, respiration cannot take car-bohydrates all the way to carbon dioxide and water. Instead the seed produces volatile organic compounds like ethanol and acetone. These leak from the seed and build up in its vicinity. These compounds indicate a terrible environment for establishment, and they inhibit germination of some species (e.g., velvetleaf). When the soil is stirred by tillage, the volatile products of anaerobic respiration are vented to the breezes and the seeds germinate in response to their absence. I suspect this germination cueing mechanism is quite common, but few weed species have been tested. The seeds are apparently not responding to oxygen itself since flush-ing the soil with pure nitrogen will prompt germination as readily as flushing with air (Holm 1972).

As can be seen from Tables 2 to 4 and the discussion above, germination response to any one particular cue

Table 2Germination response of some common weeds to light.

% Germination Species Light Dark Reference

Redroot pigweed 98 14 Kigel (1994)Annual bluegrass 89 1 Froud-Williams (1985)Common purslane 28 12 Povilitis (1956)

Table 3Percentage germination of redroot pigweed seeds in response to temperature in five northern states. Computed fromMcWilliams et al. (1968)

Location Populations tested 68° F 95° FMichigan 1 0 90Minnesota 1 15 100New York 5 6 93North Dakota 17 23 80Vermont 1 15 93


Weed Management 65

is rarely absolute. Rather the cues act cumulatively, and one cue can often replace another (Vincent and Roberts 1977, Roberts and Benjamin 1979). If no cues are present, a few seeds may germinate, essentially by mistake. If several cues are present, most seeds will germinate. If just one or two cues are present, some fraction will germinate. This partial response to multiple cues essentially hedges the bet each weed species is making about the suitability of the environ-ment for establishment and growth. If the environ-ment is maybe OK but not perfect, some individuals will germinate whereas others in a slightly different physiological state or microenvironment will wait, perhaps for years.

The management consequences of weed seed response to germination cues associated with near surface tilled conditions is that you can often trick weeds into ger-minating on command. A short period of bare fallow before or after the crop signals the weeds to germinate but gives you the opportunity to then cultivate and get rid of them.

Season of germination

All plants that live in a seasonal climate like the Northeast face the problem of knowing what time of year to germinate, and weeds are no exception. Every season has weeds that are specialized on that time of year (Figure 3, page 66).

A few weed species, like velvetleaf and common bind-weed have hard seed coats that prevent the seeds from absorbing water. The seed coat changes with exposure to soil conditions: organic acids, microorganisms and freeze-thaw cycles produce cracks or open specialized pores that allow water to enter the seed. Then, if the environmental cues are right, the seed germinates. Since winter represents a long period for these changes to take place, species with hard seeds usually germi-nate and emerge mostly in the spring with a trickle of germination through the rest of the growing season.

Most weed species, including many with hard seed coats, have physiological mechanisms that control

Table 4Effects of constant and fluctuating temperature on germination of common chickweed seeds in the dark. In thealternating temperature treatment, the high temperature was held for 8 h and the low temperature for 16 h. Extractedfrom Roberts and Lockett (1975).

Regimen Temperature (°F) Germination (%)Extreme alternating 50/86 98Constant low 50 48Constant high 86 2Constant middle 68 65

Low temperature alternating 59/77 97Constant low 59 77Constant high 77 12Constant middle 68 65

High temperature alternating 68/86 84Constant low 68 65Constant high 86 2Constant middle 77 12

Mean of alternating 96Mean of middle 47



Figure 3Seasonality of seedling emergence for eight weeds in the southern United Kingdom(RedrawnfromMohler2001basedondatafromLawsonetal1974)


Weed Management 67

when the seeds germinate. Some species will germi-nate immediately after falling from the parent plant, if the appropriate cues are present. These species follow the path from no dormancy to immediate germination shown on Figure 4.

Many weed species, however, cycle between a dormant and nondormant state during the course of the year (Baskin and Baskin 1985). For example, common ragweed is primarily a spring germinating species. Seeds are shed from the parent plant in a dormant state. As they are exposed to cold temperatures during the winter, they become “conditionally dormant.” That is, if conditions are just right, they will germinate. After a longer exposure to cold (4-6 weeks) they lose dormancy and will germinate under a wide range of conditions. So when the weather warms in the spring you often see a flush of ragweed seedlings. However, if the appropriate germination cues are absent, and the seed cooks at summer temperatures, it will again become dormant (Baskin and Baskin 1980). That is, it will be unable to germinate even if given optimal germination conditions. Ragweed takes several months

to mature and this mechanism essentially protects the seeds from germinating in late summer or fall when successful reproduction would be unlikely.

Subtleties abound with the annual germination-dor-mancy cycle. Shepherd’s-purse, for example, behaves much like ragweed, but with a slight difference. It germinates best at relatively low temperatures and will germinate in the spring. Unlike ragweed, however, shepherd’s-purse only becomes conditionally dormant at high temperatures (Baskin and Baskin 1989). Con-sequently, when temperatures cool in the fall, more seeds will germinate, including some of those shed the previous spring. Thus the species behaves as both a spring and a winter annual in the Northeast, and in cool, wet summers it will germinate all summer.

The management consequences of weed seasonality relates to crop rotation. A spring germinating species will fare poorly in a fall planted crop like spelt or a rye cover crop because the new seedlings will have to compete with a dense stand of well established plants. Similarly, summer germinating weeds like purslane

Figure 4Relationships among states of seed dormancy for weed seeds with physiologically controlled dormancy(reprintedwithpermissionofCambridgeUniversityPress;fromMohler2001, Ecological Management of Agricultural Weeds)



will do poorly in a good stand of a long season crop like soybeans. In both these cases, many of the weed seeds will not even germinate because the appropriate cues are not there at the right time. Natural processes then have another year in which to kill off the seeds. The extreme of this latter process occurs when the ground is planted with a sod crop for several years. Weed seeds under the sod do not receive the appro-priate germination cues, and any that germinate acci-dentally are killed by competition or mowing. Hairy galinsoga is the worst weed problem many vegetable growers face because they grow annual crops every year. In contrast, I have never seen a dairy farm with a galinsoga problem because they rotate annual crops with sod crops, and the galinsoga seeds die out during the sod portion of the cycle.

Seed longevity

This brings me to the topic of seed mortality and its converse, seed longevity. Unlike humans, weed seeds do not have a more or less given lifespan. Rather, their probability of death remains about equal each year, as-suming the environment is constant. That is, weather, management practices, or other conditions may lead to greater or lesser mortality in any given year, but if conditions are constant over a series of years, then a constant percentage of seeds will tend to die each year. If seeds took out life insurance, the annual payment for an 80 year old would be the same as for a 20 year old. Consequently, asking how long a particular species lasts in the soil is nearly meaningless.

Various species differ in their rate of death (Table 5). Some species survive well, with only a small per-centage dying each year. In undisturbed agricultural soil the death rate of buried lambsquarters was less than 10%/year in the particular experiment shown in Table 5. In really favorable conditions the death rate is probably even lower: viable lambsquarters seeds have been recovered from under the foundations of medieval European buildings. For other species, like common groundsel and hairy galinsoga, the seeds die off rapidly, even when undisturbed.

Of course, in an agricultural field the seeds are rarely undisturbed. Rather, the field is tilled, a seedbed pre-pared and often the soil is cultivated later in the season. Debris may be disked under in the fall or the ground chisel plowed in preparation for the next season. As I discussed previously, this soil disturbance cues seeds

to germinate. Some of these will appear as seedlings and have to be dealt with, but many others never make it out of the soil due to attack by soil organisms or being buried too deeply for emergence. Regardless of its other benefits or problems, tillage and cultivation tends to deplete the soil seed bank.

Seed size and crop-weed competition

I have mentioned several times that most weeds have very small seeds. In particular their seeds are small relative to the seeds of most crop species (Table 6). This size differential gives the crops a critical head start over the weeds. Of course, some vegetable crops also have small seeds (for example, lettuce, cole crops, tomato, pepper). On organic farms, the great majority of small seeded vegetable species are transplanted into the field, which gives them the same sort of head start that the large seeded crops have over the weeds. A conventional vegetable grower may direct seed cole crops, tomatoes or leaks and use herbicides to control the early weeds. For an organic farmer, the extra labor of weeding a direct seeding is likely to exceed the cost of growing transplants.

The differential in seed size has several consequences. First, it makes within row weeding possible. For ex-ample, you can take a tine weeder over many large seeded crops before they are up or while they are

Table 5Seed mortality as percentage loss per year in cultivatedand uncultivated soil over a 5 year period. Calculatedfrom Roberts and Feast (1972).

Species Cultivateda UncultivatedShepherd’s-purse 43 24Lambsquarters 31 8Black medic 30 22Annual bluegrass 26 22Prostrate knotweed 47 16Wild buckwheat 50 25Common groundsel High 45Common chickweed 54 32Persian speedwell 54 22Field violet 40 15

a Soil was stirred four times per year.


Weed Management 69

Figure 5Proportion of a large seeded crop (corn) and a small seeded weed (redroot pigweed) that emerged through various rates of rye straw applied as a mulch at planting. Each species was planted at a depth that had produced high emergence rates without mulch in previous experiments.(Mohler,unpublisheddata)

still small without killing the crop. The crop is rooted below the depth of penetration of the weeder (usually about 1 inch), but as I pointed out earlier, most of the weeds are emerging from the top inch of soil and are therefore susceptible. All in-row weeding tools rely on this differential between the size of the crop and the size of the weeds, including rotary hoes, Buddingh finger weeders and Bezzerides torsion weeders, spring hoes and spinners.

Another important consequence of the seed size differ-ence between crops and weeds is that crops can emerge through substantial layers of mulch whereas weeds are suppressed (Figure 5). If our weeds had seeds the size of corn or beans, mulch would be a completely useless way to suppress them.

Finally, because the crop usually gets a head start over the weeds, with some planning, it is often possible to

Table 6Propagule weight for the five most common annual weeds of field crops in New York state and for the five annual fieldcrops with the greatest acreage in New York State. Weeds and crops are listed in order of seed size not importance oracreage. Excerpted from Mohler (1996).

Weed species

Propagule

weight (mg)a Crop species

Propagule

weight (mg)a

Velvetleaf 9.5 Corn 250Common ragweed 4.4 Soybean 220Wild mustard 2.2 Wheat 39Lambsquarters 0.74 Oat 35Redroot pigweed 0.44 Rye 27

a American units of weight do not include familiar units appropriate for expressing seed weights. Onelettuce seed weighs about 1 mg.



keep the crop in a competitively superior position. Weeds are gap fillers – they are adapted to grow rapidly in the absence of competitors, and with few exceptions they grow poorly in shade. Sometimes the crop can be made more competitive by using a higher planting density, or planting multiple rows on a bed. If that is practical, then the crop canopy will close sooner, and the weeds will be at a greater disadvantage. Similarly, if the row has a skip, that is an opportunity for weed growth. Consequently, skips should be replanted. If the crop stand is poor over a large area, it may be cheaper to disk the crop under and replant or plant some other crop rather than cope with the extra expense of weed control. In my experience, something like 80% or more of weed control comes from crop competition rather than from cultivating or hand weeding. Make sure there is always a crop or cover crop there to provide that control.

Another trick to increase crop competitiveness is to direct water or nutrients toward the crop rather than broadcasting them generally over the field. Drip ir-rigation favors the crop relative to the weeds more than sprinkler irrigation because the water is released near the crop roots rather than over the whole field. Similarly, if a concentrated nutrient source like bone or blood meal is used to give the crop a boost, it is best to weed first, and band or sidedress the material near the crop. Most weeds are luxury feeders that will rapidly take up and concentrate mineral nutrients. Several studies have shown that weeds often have one to three times higher concentrations of N, P and K than the crops with which they are competing (Vengris et al. 1953, Qasem 1992). Some studies have shown that the slow release of nutrients from green manure or compost favors growth of crops relative to weeds (Dyck et al. 1995, Gallandt et al. 1998). This makes sense biologically, but too few studies have been done to make a generalization yet.

The problem with the initial size advantage of crops is that it is usually short lived. This is because most weeds have a higher relative growth rate than the crops with which they compete. This is partially due to the difference in seed size and partially due to differences in their growth forms and ability to take up nutrients. The relation of seed size to growth rate is particularly interesting (Table 7). Large seeds make large seedlings, and these grow faster in an absolute sense of weight of tissue added per day. However, larger plants have

a higher percentage of tissue in non-photosynthetic parts like roots and stems relative to leaves. Conse-quently, the relative growth rate (that is, weight gain/unit weight/day) of species with large seedlings is less. A financial analogy would be two individuals, one of which (the crop) starts with more capital, but the other (the weed) invest at a higher rate of compound interest. Consequently, weeds that start out so small you can barely see them may eventually overtop the crops. This is why early weeding while the weeds are still tiny and easy to kill is so critical to a good organic weed control program.

Seed production

As I mentioned in the introduction, weeds have adapted to frequent disturbance by partitioning their reproduc-tive output into lots of small seeds rather than a few large ones. This spreads risk and increases the chance that one or more seeds will grow to maturity.

The seed production capacity of weeds is astounding. A big lambsquarters or barnyardgrass plant can pro-duce over 100,000 seeds. I once sampled a large, open grown pigweed that produced an estimated 250,000 seeds. A student of mine grew some hairy galinsoga in pots and carefully collected the seeds as they formed. Plants a little bigger than a basketball produced 40,000 seeds apiece.

I will emphasize that big plants have many more seeds than small plants. Compare, say, two redroot pigweed plants. If one is twice as tall, or twice as big around, it will not have twice as many seeds but rather, many, many times more seeds (Mohler and Callaway 1995). Consequently, removing large individual weeds is important for long-term weed management, even if it means hand rogueing the field. Fortunately, most weed seeds come from a few large plants (Figure 6). The little plants may produce enough seeds to maintain the population, but they are unlikely to create a rapid increase in weed density.

Also, when rogueing mature or nearly mature plants, be sure to remove them from the field. Many weed spe-cies can set seeds even after they have been uprooted if the flowers have opened. Dandelion flowers will set seeds even if they have been severed from the plant and incorporated into the soil!


Weed Management 71

Figure 6Distribution of estimated seed production in a population of 231 redroot pigweed plants growing in sweet corn. Sweet corn was planted in early June and weeds emerged primarily in July after the dissipation of atrazine(RedrawnfromMohler2001,seeMohlerandCallaway1995)

Table 7Seed weight, initial growth rate, and relative growth rate of five annual plants with seeds of various sizes. Excerptedfrom Siebert and Pierce (1993)

Species

Seedweight

(mg)a

Initialgrowthrate(mg/d)

Relativegrowthrate(mg/mg/d)

Lambsquarters 0.41 0.14 0.36Velvetleaf 7.8 1.9 0.24Cocklebur 38 7.1 0.19Sunflower 61 12 0.20Soybean 158 24 0.16

a American units of weight do not include familiar units appropriate for expressing seed weights. Onelettuce seed weighs about 1 mg.



Seed dispersal

Many plant species have specializations that encourage the dispersal of seeds by animals or by wind, including fleshy fruits, hooks, bristles, fluffy hairs, and wings. A substantial portion of the perennial weeds found in pastures and hay meadows possess such specializa-tions. This is reasonable since animals are regularly in contact with these plants, and vegetative reproduc-tion insures the persistence of the population even if many wind-dispersed seeds are blown into unfavorable habitats.

In contrast, few weeds of regularly tilled fields show any of these adaptations. On the contrary, most weeds of tilled ground have small, round, nearly smooth seeds that fall within a few feet of the parent plant. This poses an apparent contradiction: some of the world’s most widespread species appear to lack capacity for dispersal. The resolution to the contradiction is, of course, that they have been moved around by people. They move in poorly cleaned crop seed, in feed grain and then in the manure when it is spread, on tractor tires and tillage machinery, and on combines and other harvesting equipment (Mohler 2001).

An interesting bit of biology lurks within this dispersal by humans. As discussed previously, most species of weed seeds are highly resistant to decomposition. They persist in the soil for long periods, and consequently can build up to high densities that make dispersal on machinery likely. Moreover, most species pass unharmed through the digestive tract of large grazing mammals. Prior to human agriculture they probably thrived best in animal disturbed habitats (bare ground and high fertility), and moved about within the guts and in soil caked on the fur of migrating animal herds. I can easily imagine ragweed seeds moving many miles caked to the fur of wandering bison or mammoths.

Probably, however, none of the weeds on your farms reached there in prehistoric times. The land survey records indicate that over 97% of the landscape of western New York was forested in the 1790s, and most of the balance was in wetlands, blowdowns and recent burns (Marks and Gardescue 1992). With few exceptions, agricultural weeds do not grow in forests or wetlands, even when they are disturbed by natural processes. Rather, these weeds mostly arrived on your farms after Europeans settled the land. The critical

question is, are new weed species still arriving on your farm?

The spread of velvetleaf makes a good example of the way civilization moves weed species around the landscape. The “Flora of the Cayuga Lake Basin, New York” (Wiegand and Eames 1925) lists velvetleaf as “infrequent” and gives six locations one could go to see this species in an area of about three counties. Velvetleaf was introduced from India to the southern colonies as a fiber crop in the Eighteenth Century. It subsequently spread to the Midwest with the westward migration of agriculture. During the late Twentieth Century it spread throughout the Northeast, probably in feed corn as dairy farms began importing more con-centrates from the Midwest (Mt. Pleasant and Schlather 1994). Since the seeds readily pass through the bovine digestive tract, the farmers spread the weed on their fields with the cattle manure. As a result, about half the fields in New York now have velvetleaf. Since the seeds are very persistent in the soil, these fields will probably have velvetleaf for as long as they are farmed.

Conclusions

Agricultural weeds are not simply unwanted plants. Rather they are species with particular biological characteristics that set them apart from most other species, including most crops. These characteristics adapt them to the frequently disturbed conditions and high resource availability of cropped fields. These characteristics include:

• Resprouting from damaged roots and rhizomes of perennial weeds,

• Ability of seeds to recognize suitable conditions for germination, including proximity to the soil surface, the absence of competing plants, the presence of essential resources like nitrogen and water, and an appropriate season of the year for subsequent growth,

• Massive production of small seeds that persist for years to decades in the soil,

• Ability to rapidly take up and concentrate macro-nutrients.


Weed Management 73

Although these characteristics adapt weed species to prosper in cropped fields, they also provide opportuni-ties for management.

• Breaking up perennial roots and rhizomes increas-es the number of shoots of wandering perennials, but each of the subsequent shoots is weaker and more easily managed by cultivation or competi-tion. Removal of above ground shoots forces the perennial to move resources from the storage organ into new shoots, thereby decreasing its ability to survive over the long term.

• Understanding of the germination biology of an-nual weeds allows the farmer to trick the seeds into germinating at times when they are easily controlled, for example, by a short period of clean fallow or a smother crop. Rotation of crops with different seasonality presents some species with in-appropriate conditions for germination each year, thereby allowing attrition by natural processes to decrease soil seed banks.

• Recognition of the seed production potential of weeds and how this varies with weed size makes the economics of preventing seed production more

attractive.

• Finally, the great difference in size between weed seeds and crop seeds or transplants allows for in-row mechanical weeding of many crops, and is a fundamental reason organic mulches are effective for weed management.

Much remains to be discovered about the biology of weeds. Germination requirements have been fully analyzed for only a few species. More critically, effects of the soil environment on weed growth and competi-tion with crops has been little studied. In some cases, slow releasing forms of nitrogen like compost and green manure appears to favor crops whereas chemi-cal fertilizers appear to favor weeds, but the generality of this phenomenon has not been demonstrated. The role of micronutrients and ratios of macronutrients are widely believed among organic farmers to be impor-tant for both crop growth and weed competition, but these topics have received little systematic research, particularly in organic systems where effects are less likely to be masked by intensive chemical management of crops, weeds and soils. Hopefully, the recent growth in the organic sector will spur increased investigation of these topics.



References

Ascard, J. 1994. Soil cultivation in darkness reduced weed emergence. Acta Horticulturae 372:167-177.

Baskin, J. M. and C. C. Baskin. 1980. Ecophysiology of secondary dormancy in seeds of Ambrosia artemi-siifolia. Ecology 61:475-480.

Baskin, J. M. and C. C. Baskin. 1985. The annual dormancy cycle in buried weed seeds: a continuum. BioScience 35:492-498

Baskin, J. M. and C. C. Baskin. 1989. Germination responses of buried seeds of Capsella bursa-pastoris exposed to seasonal temperature changes. Weed Re-search 29:205-212.

Buhler, D. D. 1997. Effects of tillage and light en-vironment on emergence of 13 annual weeds. Weed Technology 11:496-501.

Chancellor, R. J. 1964. The depth of weed seed ger-mination in the field. In Proceedings of the 7th British Weed Control Conference, pp. 607-607-613. British Crop Protection Council: London.

Dyck, E., M. Liebman, and M. S. Erich, 1995, Crop-weed interference as influenced by a leguminous or synthetic fertilizer nitrogen source. I. Doublecropping experiments with crimson clover, sweet corn, and lambsquarters. Agriculture, Ecosystems and Environ-ment 56:93-108.

Froud-Williams, R. J. 1985. Dormancy and germina-tion of arable grass-weeds. Aspects of Applied Biology 9:9-18.

Gallagher, R. S. and J. Cardina. 1998 Ecophysiologi-cal aspects of phytochrome-mediated germination in soil seed banks. Aspects of Applied Biology 51:1-8.

Gallandt, E. R., M. Liebman, S. Corson, C. A. Porter, and S. D. Ulrich. 1998. Effects of pest and soil man-agement systems on weed dynamics in potato. Weed Science 46:238-248.

Górski, T. 1975. Germination of seeds in the shadow of plants. Physiologia Plantarum 34:342-346.

Håkansson, S. 1971. Experiments with Agropyrop repens (L.) Beauv. X. Individual and combined effects of division and burial of the rhizomes and competition from a crop. Swedish Journal of Agricultural Research 1:239-246.

Håkansson, S. 1982. Multiplication, growth and persis-tence of perennial weeds. In Biology and Ecology of Weeds, ed. W. Holzner and N. Numata, pp. 123-135. Dr. W. Junk: The Hague.

Holm, R. E. 1972. Volatile metabolites controlling germination in buried weed seeds. Plant Physiology 50:293-297.

King, T. J. 1975. Inhibition of seed germination under leaf canopies in Arenaria serpyllifolia, Veronica arven-sis and Cerastum (sic) holostoides. New Phytologist 75:87-90.

Kigel, J. 1994. Development and ecophysiology of Amaranths. In Amaranth: Biology, Chemistry and Technology, ed. O. Paredes-López, pp. 39-73. CRC Press: Ann Arbor, MI.

Lawson, H. M., P. D. Waister and R. J. Stephens. 1974. Patterns of emergence of several important arable weed species. British Crop Protection Conference Monographs 9:121-135.

Marks, P. L. and S. Gardescue. 1992. Vegetation of the central Finger Lakes Region of New York in the 1790s. New York State Museum Bulletin No. 484. pp. 1-35.

McWilliams, E. L., R. Q. Landers and J. P. Mahlst-ede. 1968. Variation in seed weight and germination in populations of Amaranthus retroflexus L. Ecology 49:290-295.

Mohler, C. L. 1993. A model of the effects of tillage on emergence of weed seedlings. Ecological Applica-tions 3:53-73.

Mohler, C. L. 1996. Ecological bases for the cultural control of annual weeds. Journal of Production Agri-culture 9:468-474.

Mohler, C. L. 2001. Weed life history: identifying vul-nerabilities. In Ecological Management of Agricultural


Weed Management 75

Weeds, ed. M. Liebman, C. L. Mohler and C. P. Staver, pp. 40-98. Cambridge University Press: New York.

Mohler, C. L. and M. B. Callaway. 1995. Effects of till-age and mulch on weed seed production and seed banks in sweet corn. Journal of Applied Ecology. 32:627-639.

Mt. Pleasant, J. and K. J. Schlather. 1994. Incidence of weed seeds in cow (Bos sp.) manure and its impor-tance as a weed source for cropland. Weed Technology 8:304-310.

Mulligan, G. A. and J. N. Findlay. 1970. Reproductive systems and colonization in Canadian weeds. Canadian Journal of Botany 48:859-860.

Mulligan, G. A. and B. E. Junkins. 1976. The biology of Canadian weeds. 17. Cyperus esculentus L. Cana-dian Journal of Plant Science 56:339-350.

Povilitis, B. 1956. Dormancy studies with seeds of various weed species. Proceedings of the International Seed Testing Association 21:88-111.

Qasem, J. R. 1992. Nutrient accumulation by weeds and their associated vegetable crops. Journal of Hor-ticultural Science 67:189-195.

Roberts, H. A. and S. K. Benjamin. 1979. The interac-tion of light, nitrate and alternating temperature on the germination of Chenopodium album, Capsella bursa-pastoris and Poa annuua before and after chilling. Seed Science and Technology 7:379-392.

Roberts, H. A., and P. M. Feast. 1972. Fate of seeds of some annual weeds in different depths of cultivated and undisturbed soil. Weed Research 12:316-324.

Roberts, H. A., and P. M. Lockett. 1975. Germination of buried and dry-stored seeds of Stellaria media. Weed Research 15:199-304.

Scopel, A. L., C. L. Ballaré, and S. R. Radosevich. Photostimulation of seed germination during soil till-age. New Phytologist 126:145-152.

Seibert, A. C., and R. B. Pierce. 1993. Growth analysis of weed and crop species with reference to seed weight. Weed Science 41:52-56.

Teasdale, J. R. and C. L. Mohler. 1993. Light trans-mittance, soil temperature, and soil moisture under residue of hairy vetch and rye. Agronomy Journal 85:673:680.

Totterdell, S. and E. H. Roberts. 1980. Characteristics of alternating temperatures which stimulate loss of dormancy in seeds of Rumex abtusifolius L. and Rumex crispus L. Plant, Cell and Environment 3:3-12.

Vengris, J., M. Drake, W. G. Colby, and J. Bart. 1953. Chemical composition of weeds and accompanying crop plants. Agronomy Journal 45:213-218.

Vengris, J., S. Dunn, and M. Stacewicz-Sapuncakis. 1972. Life history studies as related to weed control in the Northeast. 7 — Common purslane. Research Bulletin 598, Agricultural Experiment Station, The University of Massachusetts, Amherst, MA.

Vincint, E. M. and E. H. Roberts. 1977. The interaction of light, nitrate and alternating temperature in promot-ing the germination of dormant seeds of common weed species. Seed Science and Technology 5:659-670.

Wesson, G. and P. F. Wareing. 1969. The induction of light sensitivity in weed seeds by burial. Journal of Experimental Botany 20:414-425.

Wiegand, K. M. and A. J. Eames. 1925. The Flora of the Cayuga Lake Basin, New York: Vascular Plants. Cornell Agricultural Experiment Station Memoir 92, 491 p.



Many organic vegetable growers consider weeds to be their primary pest problem. Integrating a variety of weed control techniques is the best way to achieve effective organic weed control.

Weed management techniques are aimed at prevent-ing weeds before they appear, or at suppressing weeds once they are present.

Weed prevention techniques include:

• Rotation of crops, fields and tillage tools

• Composting animal manures to kill weed seeds

• Cleaning farm implements between use in different fields

• Controlling weeds in hedgerows, alleys, ditches, etc. before they set seed

• Growing allelopathic cover crops

• Mulching with plastics or organic residues

• Applying pre-emergent organic herbicide (corn gluten meal)

Weed suppression techniques include:

• Growing smother crops, intercrops and/or aggres-sive cash crops

• Hand-hoeing and hand-pulling

• Mechanical cultivation

• Flame-weeding

• Applying post-emergent organic herbicide (soaps, acetic acid, etc.)

Weed prevention is essential to organic weed man-agement. Otherwise the need for cultivation can be excessive, eating into time and profits, and potentially damaging soil structure. Hand weeding is obviously costly and must be kept to a minimum. Weed preven-tion practices should begin in the years prior to planting a crop, with cover crops in a well-designed rotation. In the cropping year, clean fallowing and stale seedbeds may prepare for crop planting. Then, weed-crop com-petition can be managed through various combinations of cultivation, mulching, intercropping, mowing, and concentrating resources near the crop.

Weed Management on Organic Vegetable Farms

Vern Grubinger Vegetable and Berry Specialist

University of Vermont Extension 157 Old Guilford Rd. #4

Brattleboro VT 05301-3669 (802) 257-7967

[email protected]


Weed Management 77

Cultural practices

Crop rotation

Crop rotation subjects weeds to an ever-changing habitat, reducing the opportunity for certain species to proliferate. Rotation strategies for weed control include row versus sod crops, frequently versus rarely cultivated crops, deep versus shallow tillage crops, early- versus late-season crops, and fallow versus cash-cropped periods.

Smother cropping

Smother cropping is cover cropping with competitive species in an attempt to starve weeds of light, nutrients, moisture and space. Smothering can weaken perennial weeds by depleting their carbohydrate reserves, and can lessen annual weed pressure by slowing growth and reducing seed production. Fast-growing, high-biomass species make good smother crops because they can get a jump on, and over, weeds.

Warm-season cover crops such as buckwheat, Japa-nese millet and sorghum-Sudangrass are good summer smother crops in hot conditions, but they should not be planted until soils are thoroughly warm. Cool season crops like oats, field pea, and ryegrass are candidates for smother cropping in the early spring and fall. High seeding rates, adequate moisture and fertility, and good soil-seed contact by drilling or otherwise covering seed are important to establishing a thick smother crop.

Stale seedbeds

Stale seedbeds takes advantage of the fact that most weeds have small seeds that germinate from the top inch or two of the soil, usually within a couple of weeks of preparing soil for planting. By letting these weeds germinate and then killing them without disturbing the soil and bringing up new weed seeds, subsequent weed pressure can be greatly reduced. In some cases, growers using stale seedbeds actually encourage weed germination with irrigation or row covers to overcome dry or cool conditions that slow weed growth.

Weeds can be killed with flaming, nonselective “organic” herbicides (potassium salts of fatty acids, acetic acid, etc.) or extremely shallow scraping, after

which it is critical to minimize soil movement when planting or transplanting. Early-season stale seed-beds are often ineffective, as most broadleaf weeds germinate in warm soils. Many growers create a stale seedbed only in the crop row using a hand-held flamer, while cultivating between the rows. This works well with crops that are slow to establish, like carrots and onions.

Composting animal manure

Composting animal manure helps reduce the number of weed seeds added to the soil. In composting where temperatures reach approximately 140 degrees F many weed seeds can be killed. Maintaining the proper C:N ratio, moisture and aeration, and turning piles inside-out several times is important to ensure that most or all of the compost does indeed get hot. Turning also keeps weeds that sprout on the pile surface from go-ing to seed.

Mulching

Mulching the soil provides a physical barrier to weed growth. Organic residues such as straw, leaves, etc. can suppress weeds for many weeks if put on thickly, but they keep soil temperatures cooler which may slow the growth of warm season crops. A thin layer of organic residues can be worse then none at all, since weed prevention will be poor but cultivation may be hampered.

Black plastic mulch completely blocks light from weeds and is a very effective weed suppressor. Clear plastic mulches warm the soil to a greater extent than black plastic, but allow light to penetrate thereby encouraging weed growth. Selective wavelength mulches, such as IRT, behave in between black and clear plastic, allowing limited weed growth. If weed pressure is high and canopy growth is slow then there may be a lot of weeds under clear or IRT plastic. How-ever, under conditions of strong sunlight, solarization may kill weeds that grow under clear plastic if it is left undisturbed for several weeks prior to making planting holes in it. Paper mulches have been used with limited success since they tend to deteriorate during the season. Throwing soil up on the edges as they decompose has helped keep paper mulches in place for some growers. Organic growers need to avoid paper mulches treated with prohibited materials.



The edges of plastic or paper mulch pose a special challenge because weeds often grow well there but the mulch is easily ripped by close cultivation. To avoid hand-weeding, some growers have developed innovative cultivation tools to deal with this unique zone. These tools usually undercut then replace the mulch, or cultivate extremely close it. Both approaches require straight runs of mulch with uniformly buried edges. The planting hole may require hand weeding with slow-growing crops. Bulb planters, propane torches and other devices have been used to create small, uniform holes for planting into.

Interseeding

Interseeding is a form of inter-cropping that can add to soil organic matter, reduce soil erosion, improve field trafficability and also suppress weeds. To avoid com-petition with the cash crop it is advisable to interseed moderately competitive cover crops like low-growing clovers and/or ryegrasses into relatively vigorous cash crops like corn, potatoes or squash; to leave a bare planting strip for the cash crop that is kept free of intercrops as well as weeds; to sow the cover crop after the cash crop is well-established, usually at last cultivation; and to provide irrigation.

Mowing

Mowing (or weed-whacking) vegetation between the rows of a cash crop can control weeds, and or cer-tain intercrops. It also enhances the environment for harvesting and pick-your-own sales. In most cases, between-row mowing is only practical on a small scale, or where rows are wide enough to accommodate tractor-pulled mowers. Side-discharge mowers damage crops by blowing debris on them.

Placement of resources

Placement of resources can be used to favor crops over weeds. By banding and sidedressing fertilizer, and in some cases by using drip irrigation, weeds can be denied nutrients or water needed for good growth. A word of caution is that many plants send roots laterally to obtain resources, so locating water and fertilizer only in the row may be more useful in limiting between-row weed pressure only if the rows are far apart.

Crop establishment

Crop establishment techniques that encourage the rapid early growth of vegetables and discourage rapid early growth of weeds can minimize weed control costs. Transplants give crops an obvious jump over weeds compared to direct seeding. Carefully placed starter fertilizer feeds crops not weeds.

Cultivation

Cultivation equipment for weed control varies in ag-gressiveness and is usually suited to killing weeds either before or after the crop emerges. Tools designed for use after a crop emerges provide either between-row weed control or in-row weed control, or in some cases, both. Cultivation implements are designed to dislodge, cut and/or bury plants. Matching the tool to the weeds, crops and soil conditions is key. Juggling the uncertainties of weather and other management demands on the farm is the challenge to using a culti-vation tool at the right time.

Pre-emergence cultivation

Pre-emergence cultivation often involves shallow tillage of the soil with rotovators, various harrows or field cultivators. If performed repeatedly, this ap-proach is called a “clean fallow” that can occur before or in-between plantings. The objective is to kill annual weeds, reduce the soil weed seed bank and remove perennial weed growth. While rather harsh on soil structure and organic matter, this technique can be justified if used in combination with a good cover crop rotation and/or addition of soil amendments to maintain soil structure.

Disk harrows

Disk harrows are often used for clean fallowing, but they may not be the best choice with a perennial weed problem like quackgrass, since rhizomes tend to be chopped up and spread them throughout a field. Field cultivators are used to create a seedbed and incorpo-rate residues and soil amendments, as well as for weed control. Equipped with rows of S-tines and sweeps or shovel with lifting action, they can be used to dig up and lift quackgrass rhizomes to the surface of the soil where they will dry out and die in hot dry weather. A


Weed Management 79

variety of field cultivators are on the market, they vary in tine shape, flexibility, action, and spacing, as well as options like rollers, cultipackers, crop shields, leveling bars, and gauge wheels.

Blind cultivation

Blind cultivation relies on tools that work the entire surface of the soil ‘over the top’ of a recently seeded or recently emerged crop. The technique combines in-row and between-row cultivation, often to control weeds that have germinated but not yet emerged, the so-called ‘white-thread’ stage of growth. This disturbs and dries out small, vulnerable weeds before they start to size up alongside the crop. Such fast, shallow cultivation works best on weeds that have been up for week or less. Large-seeded crops sown deeply and young vigorous crops are able to tolerate such cultivation, while very small annual weeds cannot.

Flex-tine weeders

Flex-tine weeders can be used for blind cultivation on a number of vegetable crops. The weight of these units may be borne by the numerous thin metal tines that wiggle and dislodge weeds, or by gauge wheels attached to the frame. Gauge wheels help control tine depth and avoid gouging soil on uneven fields. With some units, the 3-point hitch can be used to adjust downward pressure on the tines. Tine weeders width ranges from narrow, bed-covering sizes to very wide units useful in large fields. Lely and Einbock are com-mon brands.

Rotary hoe

A more aggressive blind cultivator is the rotary hoe. It has many thin spider wheels each with 16 or 18 tips, or spoons, which dislodge very small weeds. The spiders move independently and bear the weight of the unit, although gauge wheels are available. Rotary hoes come in widths of 6 feet and up. They are most often used for weed control in corn and beans and for breaking up the surface of soils prone to crusting. Rocks will jam in the spiders of a rotary hoe, keeping them from turning properly. Plastic mulch pieces in the field will also collect on spider wheels and require removal. Dull spoons reduce the effectiveness of rotary hoeing.

High clearance tractors

High clearance tractors facilitate post-emergence mechanical weed control since crops up to several feet tall can pass under the tractor, and tools can be “belly-mounted” in view of the operator, increasing the precision of cultivation. Off-set high clearance tractors are even better for cultivating because the driver’s seat is off to the side of the tractor body, further enhancing vision of the row.

Cultivating tractors

Cultivating tractors are small, low to the ground, easy to guide and used only for precision cultivation of young or low-growing crops. The cultivation tools and the crop row(s) being cultivated are easily viewed by the operator. The Allis Chalmers “G” tractor, no longer made, is the classic of this type. Other brands, Hyspan, Saulkville, and Friday, are currently available.

Basket weeders

Basket weeders are metal cages that roll on top of and scuff the soil surface without moving soil sideways into the crop rows. This action makes them ideal for crops like lettuce that have to be kept free of soil and are not suited to hilling. Buddingh basket weeders are custom built for two to eight row beds. Angled baskets are available to work the sides of raised beds. Basket widths range from 2 to 14 inches depending on the space between rows. For wider widths, and for inner row widths that change as crops grow, overlapping baskets are available that “telescope” or expand in and out to adjust for the width.

Commonly used at speeds of 4 to 8 mph, straight rows and an experienced operator are helpful to avoid crop damage. The front row of baskets turn at ground speed and a chain drives the rear row of baskets a little bit faster; these kick up soil, and dislodge weeds that survive the first baskets. This tool is almost always belly-mounted to assist with close cultivation. The baskets handle some small stones but work best in fine soils free of clods and residues.

Finger weeders

Finger weeders cultivate around the stems of crop plants that are sturdy enough to handle some contact. Rubber-coated metal fingers provide some in-row



weeding. These are connected to a lower set of metal fingers work deeper in the ground and drive the unit at ground speed. These units can be used at just a few miles per hour since they are in such close proximity to the plants. They require belly-mounting, and are ideal for a G-type tractor. Wet clayey soils can stick to fingers and require frequent removal.

Brush-hoe weeders

Brush-hoe weeders are European tools for close cul-tivation in narrow rows, not very common here, and expensive. Shields protect plants from bristle wheels that rotate independently between the rows, “sweep-ing” weeds out of the soil. An operator sits behind the rotating wheels and steers the unit to assure precision.

Sweeps, shovels, and knives

Sweeps, shovels, and knives attach to the shanks (vertical pieces of metal that attach to the toolbar). Depending on their shape and orientation, these tools move soil in different ways as they are pulled between crop rows. People are not consistent in how they name these tools, so there can be some confusion. The shanks can be clamped to different places on the toolbar(s) to achieve an arrangement that provides the desired in-row coverage and extent of soil movement. Toolbars can be rear-mounted, belly-mounted (underneath a high-clearance tractor), or with special attachments, front-mounted.

Sweeps are wing-shaped, come in various sizes and angles, and are used to dig up larger weeds between crop rows while throwing soil into the row. Big sweeps, or duckfeet, are used to cultivate wheel tracks. Half-sweeps have a wing on just one side, so the wingless-side can cut closer to the crop rows or plastic edges. Shovels are narrower than sweeps, throw less soil, and sometimes have 2 points that are reversible. Knives are like angled shovels that are used to cut more horizon-tally and closer to a crop.

Wiggle-hoes

Wiggle-hoes have shanks with half sweeps attached that can be hand-steered around plants in a row by an operator seated on the back of the tractor-pulled unit. Close cultivation is possible, but extra labor is required for the operator. Slow tractor speed and wide crop spacing must be used to allow shanks to be

moved in and out of the row. The Reigi weeder has PTO-driven rotating hubs with stiff tines that can be steered in and out of the row by an operator seated behind the tractor.

Row-crop cultivators

Row-crop cultivators consist of toolbars on a tractor-pulled frame with various shanks and cultivation implements attached so as to leave space for the crop rows to pass. These are much like field cultivators except for the spacing of the shanks and the absence of implements that completely cover the soil such as rolling baskets. Shields may be mounted on either side of the crop rows to protect them from soil and rock movement during cultivation.

Spyders, spring-hoes, and torsion weeders

Spyders, spring-hoes, and torsion weeders (made by Bezzerides) are used alone or in combination for close between-row cultivation. The spyder wheel has staggered curved teeth and is ground-driven on a ball-bearing hub. A pair of 12-inch spyders can be angled at 45 degrees toward or away from the row to either pull soil away or throw it back. Aggressive and rapid cultivation of a variety of row crops is possible, even on stony soils. Torsion weeders are square stock metal bars that can be mounted to follow the spyders, level-ing the soil and flexing around the plants to clean up spots missed by the spyders. Spring hoes are flat blades 16 inches long that are a bit more aggressive than the torsion weeders, oscillating just below the soil surface.

Rolling cultivators

Rolling cultivators consist of gangs of heavy slicer tines that aggressively dig up weeds and pulverize soil between rows. Individual gang width ranges from 10 to 16 inches depending on number of slicer tines, and units are available for one to 12 rows. Gangs can be angled to hill up or throw soil into the row. Used with fertilizer attachments, sidedressing is possible while cultivating. Rocks may jam in tines, and action may be unduly aggressive for sandy soils.

Hilling disks

Hilling disks are used to aggressively throw soil into the rows of crops such as potatoes, leeks, sweet corn and other crops that tolerate or benefit from being


Weed Management 81

buried. Properly timed, this results in excellent in-row weed control.

Flame weeding

Flame weeding is the killing of weeds with intense, directed heat, usually with a propane burner. Flame weeding is used primarily to control small weeds in a stale seedbed (without disturbing the soil). Because weeds tend to emerge in ‘flushes’ stimulated by till-age, the initial emergence of weeds represents a major portion of the weed pressure in a given field, provided subsequent tillage that brings new seeds to the surface is delayed or avoided. Prior to flaming, the soil is pre-pared for planting in the normal fashion, then weeds are allowed, even encouraged, to emerge, so they can be killed with flame. After planting the crop, but just before it emerges, another flaming may be applied to kill weeds that have emerged in the interim. With slow-to-germinate crops, this final flame weeding is most critical to success.

Backpack or hand-held flamers are the simplest, least expensive and safest method of flame weeding. A small canister is carried by hand or in a backpack, while a single burner at the end of a wand is aimed at the area to be flamed. The burner size, walking speed, and flame adjustment determine how much heat is applied to an area. This technique is popular for small plantings of crops that will later be close-cultivated between the rows but will not tolerate soil being thrown into the row. For example: carrot, lettuce, radish, spinach, herbs, etc.

Tractor-mounted flame weeders have been custom-built by growers to flame multiple rows or wide beds. The components include a tank (or several), valves, gas lines, regulators, pilot lights, and emergency shut-off. Gas may flow directly to individual burners, or it may be distributed through a manifold first. Burners are specific for propane in the gas or the liquid phase

and are available with different BTU ratings. Liquid burners can avoid ‘ice up’ of gas lines. Burners may be arranged in a row to flame the entire width of a bed, including wheel, or they may be aimed at or between the rows. They may be fixed to the unit, or adjustable. Having individual burner shut-off valves and angle adjustments provides flexibility in how a flame weeder can be used.

Tractor speed when flaming is just a few mph. The larger the weeds or the heavier the dew, the slower trac-tor speed needs to be. Flaming is not intended to burn the weeds, but to provide a short exposure to intense heat which ‘blanches’ the weeds, and they collapse and die within minutes or hours. Exceptions to this are grasses, with below-ground growing points, and some succulent weeds like purslane, which can take the heat. These weeds require hotter temperatures and/or subsequent cultivation to control.

The propane containers used on tractor-mounted flamers must be ‘motor fuel’ tanks, which are rather expensive, but intended for mobile use, unlike station-ary propane canisters. The design of the system and the selection of valves and controls should be done in consultation with a propane professional. All tractor mounts, canister straps, and lines should be carefully examined before using the flamer. Besides the potential for explosion, concerns include: fires started in dry grass or hedgerows, liability insurance and regulations.

Conclusion

Effective organic weed control on vegetable farms is possible through the use of cultural practices, cultiva-tion and flaming. Organic weed control practices can be economically viable when utilized as part of a whole-farm management system that includes rigorous use of cover crops, crop rotation, and sanitation.



References

Altieri, M. and M. Leibman, 1988. Weed-Crop Ecol-ogy: Principles in Weed Management. Breton Publish-ers, Boca Raton FL

Colquhoun, J. and R. Bellinder. 1997. New Cultivation Tools for Mechanical Weed Control in Vegetables. IPM Fact Sheet, Cornell Cooperative Extension, Ithaca NY

Bowman, G. (ed.) 1997. Steel in the Field: A Farmer’s Guide to Weed Management Tools. Northeast SARE Program, UVM, Burlington VT

Grubinger, V.P. and M.J. Else. 1996. Vegetable Farm-ers and their Weed Control Equipment (video) Center for Sustainable Agriculture, UVM, Burlington VT

Some sources of cultivation equipment

Bartschi-Fobro LLC P.O. Box 651 Grand Haven, MI 49417 (616) 847-0300

Bezzerides Bros., Inc P.O. Box 211 Orosi, CA 93647 (559) 528-3011

BDi Machinery Sales Co. 430 E. Main St. Macunie, PA 18062 (800) 808-0454

Buddingh Weeder Co. 7015 Hammond Ave. Dutton, MI 49316 (616) 698-8613

Chauncey Farm 119 Bridle Rd. Antrim, NH 03440 (603) 588-2857

HWE Agricultural Technology (Einbock) B.P. 1515 Embrun, ON K0A 1W0 Canada (613) 443-3386

Market Farm Implement 257 Fawn Hollow Rd. Friedens, PA 15541 (814) 443-1931

Lely Corp. P.O. Box 1060 Wilson, NC 27894 (252) 291-7050

Univerco (Reigi weeder) 713 Route 219Napierville, Quebec J0J 1L0 Canada (800) 663-8423 (450) 245-7152

Unverferth Manufacturing P.O. Box 357 Kalida, OH 45853 (800) 322-6301

Wasco Hardfacing Co. P.O. Box 2476 Fresno, CA 93745 (559) 485-5860

Mention of brand name equipment, suppliers, and prices is for information purposes only; no guarantee or endorsement is intended nor is discrimination implied against those not mentioned.


Weed Management 83

How to Get 99% Weed Control without Chemicals

Brian Caldwell Farm Education Coordinator


In order to grow a vegetable crop to its full potential, weed control needs to be good, really good!

How good?

Often, dozens or hundreds of weed seeds per square foot of vegetable field will sprout, ready to out-compete your crop. Even if 90% of those seedlings are killed, that can leave several survivors per square foot--more than enough to hurt yields. 99% or more of emerging weeds must be prevented from competing with the crop. This translates to less than one weed per square foot (note: we’re not talking about a “99% clean” field--there still might be thousands of weeds per acre, just not enough to hurt yields). Some growers do this routinely, without herbicides and with minimal hand weeding.

In order to consistently get this 99+% control, four strategies must be combined:

1. Preplant weed control

2. Weed control between rows

3. Weed control within rows

4. Reducing weed reproduction

Skipping one of these strategies will result in too many weeds and a yield loss or the need for expensive hand labor to get rid of them.

Preplant weed control

Preplant weed control starts with the right tools. The strategies described here can be done with hand tools and walking tractors, but for operations of over an acre, tractor-mounted equipment is worthwhile. Investing in good used equipment will quickly pay off in reduced labor and better results. Use compatible, effective equipment to prepare the soil and seed and cultivate the crop. Seedbeds must be level. Rows must be straight and exactly the right distance apart for the cultivator. Belly-mounted seeders and cultivators are best.

Plan crops, cover crops, and tillage to stifle weed out-breaks each year. If a long season heat-loving crop or cover crop is grown one year, follow it with an early or late cool weather crop. Vary tillage times and crop types (long or short season, warm or cool weather crops) from year to year, in addition to not repeating related crops in a field. Deep tillage at different times during the season will strongly suppress perennial weeds like quackgrass, Canada thistle, and yellow nut-sedge. If you have these weeds, plan to rotovate or plow twice a season (followed by your crop or cover crop)



until they are gone. After a few years, discing or field cultivating may be all the primary tillage you need.

Stale seedbed techniques can knock out your first 50- 75% or more of the weeds. The best non-chemical approach for this is to prepare a fine, firmed seedbed 2 or more weeks in advance. When it’s time to plant, go over the seedbed using flaming or a shallow cultivation with a basket weeder to kill the emerged weeds. Plant your crop right away, with no further soil disturbance. Many fewer annual weeds will emerge to compete with the crop. This method works better for crops that are planted during warm weather (June or later), so that weeds have had a chance to germinate.

Weed control between the rows

Weed control between the rows is relatively easy. Pictures of some common types of cultivators can be found in Steel in the Field, edited by Greg Bowman, the best reference on mechanical weed control. If you want to control weeds without chemicals, you need this book. You can order it at 802-656-0471 for $18.

Growers on stone-free soils tend to prefer basket weeders, which allow cultivation very close to the row and do an excellent job if weeds are less than 1 inch tall. For stonier soils or somewhat larger weeds, gangs of overlapping sweeps are also effective, but they throw more soil and must be set further from the row. “Spyder” toothed disks can be mounted next to the row to get closer. Without throwing any toward the row, they shear soil away, which is then thrown back by the following sweeps.

Cultivate early on a sunny day for best results. If you don’t have an ideal cultivator, go over the rows twice (i.e. in both directions), to do a more complete job on those weeds.

If possible, cultivating a couple days after a good rain is an effective strategy for reducing weeds and holding moisture. The loosened surface soil may form a “dust mulch,” which will hold moisture beneath, but which will not be a good seedbed for new weeds.

While cultivators kill existing weed sprouts, new seeds are stirred up and will sprout after a rain. That’s why

several cultivations are needed. I often hear growers say, “It’s a mess now, but it was clean as a whistle 3 weeks ago.” They should have cultivated at least once more, even though the weeds were barely visible.

If weed pressure has been reduced 75% by stale seed-bed, and between row cultivation gets 80% of what’s left, then we have 5% of the original weed pressure left-mostly right in the rows next to the crop. We’re at 95% weed control, close to our 99% goal.

Weed control within rows

Weed control within the row is very tricky. For one thing, research done by Dr. Chuck Mohler of Cornell and myself showed that annual weeds may come up 2-3 times more thickly within the row. Why? Be-cause they do best on a well-firmed seedbed, just like your crops. (Similarly, be sure not to leave packed soil caused by your tractor tires. Mount sweeps behind the rear tractor tires.) That in-row location is precisely where weeds are hardest to kill and where they most reduce your yield.

“Broadcast” cultivation with a flexible tine (“tine-tooth” or “finger”) weeder or a rotary hoe solves part of the problem for large-seeded crops that can be planted deeply like corn, beans, peas, potatoes or onion sets. The implements are pulled at high speed “blindly” right over the crop rows, scratching out the newly-sprouting weeds while going right over deeper crop seeds or better-rooted crop seedlings. This is usually done 4-5 days after the crop is planted, then a week later, and perhaps once more. The crop shoots get a bit beat up by the process, and a few are pulled out of the ground, but yield is reduced only slightly or not at all. Most of the weeds within the rows are killed, so the broadcast cultivation is quite worthwhile. But it must be done when the weeds are in the “white thread” stage—just before emergence—to be effective.

After the crop is too big to broadcast cultivate, the between-row cultivators are used. For the last one or two between-row cultivations, soil can usually be purposely thrown at the base of the crop (“hilling”), smothering small weeds coming up in the row.

If we can kill 80% or more of the in-row weeds with


Weed Management 85

broadcast cultivation and hilling, our 5% of the original weed pressure has been reduced to 1% or less. We have reached our 99% goal.

There are variations in this strategy for some crops. Potatoes, for instance, are deeply hilled. If this is done twice, good weed control is usually attained. Trans-planted crops like brassicas cannot be blind cultivated, but they quickly grow to the point where they can take some hilling. The trickiest crops are root crops like carrots, parsnips, beets, direct-seeded onions, or herbs like dill, cilantro, etc. They usually require some hand weeding. Turnips and daikon are often seeded after mid summer when weeds pressure is not so strong, so hand weeding is light. A special trick can be done with carrots and parsnips, which are slow to germinate. Just before the crop comes up, but after the main flush of weeds has germinated, the rows can be flamed. Weed control is excellent when this is done right. If a small pane of glass is placed over part of a carrot row, the crop seeds under it will come up a day or two ahead of the uncovered rows-so the grower is alerted when it’s time to flame.

Reducing weed reproduction

What we are trying to accomplish here is to limit year-to-year weed pressure by reducing the soil weed seedbank. This is a long term process. The key prac-tice here is to till under the crop as soon as harvest is finished. This reduces new weed seed production, and also helps with disease and insect control. Seed a cover crop at the same time.

Some growers are able to send someone through the field late in the season to hand pull large maturing weeds and get them out of the field--not a bad job if weed control has been excellent.

Cover crops can also be used in other ways to compete against weeds. At the final cultivation, they can be “undersown” into the cash crop. The crop should be far enough along that the cover crop will not compete heavily against it once it gets going. Slower estab-lishing cover crops like red or sweet clover are better choices than oats or ryegrass for this purpose. In dry years, even late- interseeded cover crops will compete against the cash crop, unless the field is irrigated. On

the other hand, undersown strips can reduce mud and protect the soil during a wet harvest.

In addition to killing flushes of weeds before seeding with the stale seedbed technique, the same idea can be applied after early-maturing crops. Till the crop in, wait for a flush of weeds, kill them, then plant your cover crop. You’ve gotten rid of another batch of weed seedlings.

Finally, avoid importing millions of weed seeds by not spreading manure from grain-fed animals. Compost such manure before use.

Mulching

Mulching controls weeds both in and between the rows. All transplanted crops and garlic are candidates for mulching.

Garlic can be mulched immediately after planting with organic materials like weed-free straw, hay, leaves, or wood chips, if the soil is well drained. Annual weeds are suppressed and these materials provide organic matter and long-term nutrients to the soil. Mulching with organic materials works well for other crops too, as long as they grow well in cool soil and the field is free of perennial weeds. There is a labor cost in ap-plying these mulches, but I’m convinced that growers can figure out reasonable ways to apply them if they want to. For instance, much time is saved by laying the mulch down before the crop is transplanted (or before it comes up, as in the case of garlic). High-residue no-till transplanters are being developed that may work through organic mulch.

The other major mulching material is black or colored plastic. Weeds along the edge of the plastic can be a headache. Covering the bare soil between the plastic with weed-free organic materials is a good solution. Moisture retention, soilborne disease reduction, and a dry picking lane are bonuses. Otherwise, rows can be set far enough apart so that a narrow tractor with a section of springtooth harrow or other cultivation setup can be pulled through every two weeks or so. Hoeing or flaming will have to be done along the plastic edges. Edge weeds that go to seed late in the season can be a real drawback to the use of plastic mulch. If



you use colored plastic mulches, make sure they are able to fully shade out weeds. Some work well only with herbicides.

How much does this cost?

A rough estimate would be $30-40 per equipment pass per acre (including amortized, pro-rated equipment costs for tractor plus cultivator and flamer setups, fuel, labor, etc., used on at least 10 acres per year). For large operations, this cost could perhaps be cut in half. Hand weeding costs are likely to be at least $400/acre (50+ hrs @ $8/hr). Organic mulching materials could run on the order of $500/acre (clean straw—5 tons/A @ $ 100/ton), plus considerable labor for spreading. Plastic mulch materials are perhaps $200/acre or more,

depending on row spacing and type of plastic.

Varying intensities of weed control are needed for dif-ferent crops, and much depends on crop mix and the scale of the operation. A typical sweet corn crop might require two blind passes with a flexible tine weeder, then two between-row cultivations with sweeps and hilling discs (roughly $60-160/acre, depending on farm size). Carrots, which are worth a lot more per acre, might get stale seedbed prep, a delayed flaming just before emergence, three cultivations, and a hand weeding ($600/acre or higher).

A crucial management issue that goes along with me-chanical weed control is the need for getting the job done on time. If you do it with the right equipment, at the right time, it’s easy. Otherwise, you may be in for a tough time, or a lot of healthy weeds!


Weed Management 87

Mulching for Weed Control and Organic MatterTranscript of a presentation by:

Paul Arnold Pleasant Valley Farm

Argyle, New York

We bought this land back in 1988 and put up the houses and the barns that you see. I started in my father’s back yard for a couple of years just because I grew up in suburbia and I decided I wanted to farm and then went to play around in his back yard for a few years then bought this place in ’88. Bought land and then put up the house and all the barns you see and planted the orchard and just got things up and running. I would do a little work in the wintertime and then farmed in the summer. Met my wife Sandy right after I bought the land, she knew she was going to marry a farmer and I wanted to make sure that she really liked farming before I married her. Since then we have had two kids, they are 10 and 7 and they help quite a bit on the farm. Kim and Robert. When we started out I had my father to help me and my step-mom and they helped me quite a bit. About three years ago my father passed on, but we have been able to keep the farm going because it was a threesome for a long time. It worked really well and that is how we got the buildings up and houses up and everything else kind of going on this farm.

What we do is raise about six acres of vegetables now, we probably have about ten acres that are available to us and so some are kept in cover crop and rotation. We sell at area farmers markets, four of them. So for us a typical week starting from May 1 to November is market on Monday afternoon so we are picking Monday morning, market in the afternoon. Tuesday to do field work, Wednesday is pick in the morning

and market in the afternoon. Thursday is fieldwork, Friday is pick all day and Saturday is two markets. So that’s kind of a typical week for us. We try not to work Sunday. Usually in the early spring we will be pushing to do everything. Like I say, to get things planted and get things cultivated at the same time. It gets kind of pushing in June and May.

We grow about 35 different crops, small amounts of each one, constant planting right through from early February so we have crops from May 1st on. Usually spinach and lettuce the first week in May, and rhubarb and asparagus. We grow a small amount of perennials. A lot of our mix of vegetables is to have a consistent amount through the whole year and that is how we kind of control our income is to always have something coming on because we all know it is a good year and bad year for something. With the just two days a week that we all have to do field work we have really had to be efficient at our cultivation and be efficient at trying to prevent weeds. This is why we got into mulching. In Washington County we are a dairy county primar-ily but right around me there are not really any dairy farms. To haul manure or bring in stuff like that was difficult in the early years so we looked to what we had and one thing we did have around us a lot was hay fields that were being unused. That became our source of building our soils. What we actually bought on this farm was a corn field. Probably continuous corn for 30 years. So we had a couple of years of cover crops



and we started right in after getting some equipment putting on hay mulch trying to build up organic matter because it was only a little over 2%. This is where we kind of started.

We have a slope here going down. From here to the house is north and so we are kind of on a northeast slope with good northwest protection of trees and this makes this ground very early. We have other fields and a 120 acre farm next door that we rent. We have plenty of hay fields and ability to rotate. On top of growing vegetables we have about an acre of fruit and one thing we set out to do to make sure is we always had fruit on the table so we had a lot of different small fruits and apples on top of that. Not too much of anything. We hardly grow an acre of anything.

One of my goals of getting into farming, and I was pretty naive when I got into it, was the fact that I did not know that farmers did not make a living at farm-ing. I got told that quite a bit when I first got started and I told them this is what I am going to do and I am going to make a living at farming. I am going to make a living at farming because I wanted that lifestyle of staying home and raising food for my family and sell-ing. Even though I was told by pretty much everybody and I hate to say the Extension Service that it wouldn’t work but I don’t think they have the models at that time like they have now to show that it does work. This is going on 15-16 years ago. So we set out to do it and so far with the goals that I have it has worked very well. We have been able to make a living at farming for 10 years. We have never worked outside the farm and have been able to reach our goals of making this a good income. With being able to be so diversified and having an unlimited water supply, a good irriga-tion system and good markets were we are we have been able to have a consistent income and not really have any of this roller coaster up and down. That has been good for us.

This is shot from across the valley because we are on the edge of the valley. The apple trees are grown where they are because there is quite a slope. We have made conscious decisions as to where to plant stuff and because we are up off the valley floor we really stay away from the frost. What we have for soils is up on top we have rocky silt looms and down below the lower fields are sometimes a little heavier clay. It makes rotation sometimes tough because you can’t always put it where you should rotate but you put it

in the best place you can. You don’t want to put spring and fall crops in the lower areas.

Here is a shot from the house showing all the diver-sity we have – little bits of a lot of different things. We kind of break it up into knowing what crops are going to be there all year and what crops are going to be coming and going really quick like lettuce and some of the ones that are there all year like tomatoes and peppers.

This is going back toward the house. This is our main field where we started and as we grew we did more and more acreage. We kind of started right from the beginning trying to put down mulch and we tried dif-ferent things. You can see right here we have zucchini and cucumbers and we tried sawdust from a horse farm and found that it really tied up nitrogen bad. After a year, when this broke down it made the best soil on the farm but meanwhile there was a lot of starvation for nitrogen. It held things down pretty well. There were a few escapees there but it made life a lot easier putting down mulch because there was just that much less area that I had to cultivate.

Just a little diversity of a lot of different crops that we are growing, lettuce. This is where we are putting down mulch and after the mulch is turned under from the year before trying to grow lettuce through the summer. Looking for high organic matter for these real high demand crops especially when it gets to be 90 degrees you are really happy it has a lot of organic matter down. When we were putting a lot of mulch down we were doing a lot of it for fertility. We have gone on to now without a lot of extra hands, like my father, around we have gone into doing compost be-cause it is a lot faster. We are constantly evolving and if I come here another three years from now I might be doing something totally different again. I think that is one thing you always do is you are always evolving and changing and finding better ways and using the best use of your time and equipment that you have. Compost came around because we finally got a front-end loader and we just had to buy a manure spreader and also it became available around our area to get compost. Back when I first started we did not have a choice there wasn’t anything else to get. There was no compost except for along long distance away. This is how we are holding our organic matter now.


Weed Management 89

Let’s talk a little bit about cultivation that we use. Because we are really tight spacing just because some-thing is older and not a new product – this still worked very well for the first few years on the farm. Somebody gave it to me and I put it to use and it did very well. It is like anything else, I talked about even with tractor cultivation, you can’t buy one cultivator and expect it to do everything so this works well as long as you are using it in combinations with other things. If you just use this those few escapees are going to get by and you are just going to have a problem with one weed. A lot of these older tools work really well. This is a typical wheel hoe and it worked well for us for crops that are straight up and down and with walk paths and wider areas where you can really go along quite quickly. A lot of different attachments you can get down at the bottom here. Wider ones. You can also get kind of a duckbill one.

When we first got going a lot of our crops that we were cultivating were on 12 inch centers. We were just packing stuff in. We did not have a lot of land. We were land limited and we needed to get things in close, close spacing and so cultivation with these smaller tools were the most efficient thing. You do not need to start out with tractors right off the bat. Starting out with these smaller tools like that push hoe I showed you, the wheel hoe and that little push cultivator were very effective up until five years ago for us and were a real time savings. I think you get to a certain size and time when all of a sudden priorities change a little and you find you can change and add some new tools, some tractor mounted stuff when you finally can evolve to own tractors that will do the job that you want it to do. We do not have a picture of it but we depend mostly on your Farmall 200s or Super-Cs that are a little bit bigger than a cub or a little A that they sometimes show. We found that we can do two rows at once and also with the Super-C you can get real wide spacing. We are doing four rows underneath our Super-C on 14 inch centers. That is very efficient to be doing four rows underneath the tractor than to be doing three because of the amount of rows you can get done within a time. As we have evolved we are still using push hoes, we are still using some tractor cultivation for crops that are just there for a short time like beets, carrots, lettuce, spinach and crops like that. What happens is we start getting into using mulching. Where we use mulching is mostly the crops that are going to be there all year – tomatoes, peppers, cucumbers. Areas like that. A lot of it is grass mulching. We are cutting the grass out

in the fields and bringing it in and laying it down. It is kind of a whole farm approach. If you just looked a the economics of just putting down the grass mulch and just left it at that you would probably say it is a losing venture but the fact is if you look at the whole farm approach and you are trying to increase organic matter, trying to make the most of your soil on top of single and double cropping on close spacing, having that organic matter and rotating that around your farm in these mulched areas you can build organic matter. We have gone from I think it was like 2.1% when we first got there and all these years we have never really given that main field you have been seeing up there a rest and we have been able to increase it to at least 4.5% now. Five years of mulching and a little bit of compost the last few years. Mulching – you have to be able to look at that and say it is a good whole farm approach not just a matter of what it is doing for you at that moment. So we are using grass mulch and we are also using straw mulch. We are buying in straw from a neighboring farm and this is something really important and I know people have gotten themselves into trouble is that we work with the farmer and we ask him to cut the straw before it goes into pollen. He does that for us and we are paying a little extra for it but the reason is there is no seed in it. If you are getting straw and if you are going to buy it for mulching and they have already combined it there is plenty of seed in it. There is a lot they can only get out so much. You can get yourself a real weed problem. With using the straw mulching it is really important to either raise it yourself and cut it at the right time or hire somebody or get some farmer near by to do it for you.

We mulch asparagus, that’s how we keep the weeds out of that. Its funny with asparagus you think that it’s a high value crop and its not. It barely breaks, what we call a $10,000 an acre rule, something has to make at least $10,000 an acre although of course you know we barely grow an acre of anything. But the asparagus just barely makes it over that. It seems like a really high value crop, but its just a nice thing to have in May and June.

We mulch raspberries and blueberries. I don’t have a picture of the blueberries but we mulch them both with wood chips. There are a lot of businesses that go along and they are chopping where the power lines are going through so we get all of our wood chips for free. And also if we have any shavings left over from the chickens they go on there. But we will go ahead



and cover this up with something that is going to stay there a long time. We do this once every few years just put down a lot of chips on this instead of putting hay down every year. These are the fall ones that we are going to turn under and we’ve got the drip irrigation on them. And to make them come in a little earlier we put the row covers over the top of them. And so we can get Heritage raspberries coming in, in August.

Some of the crops we are going to put out when we go out there are Swiss chard. We are using soil block lots of times on the bigger seeded stuff like this. Stuff like lettuce is usually going in as seedlings and these grow really well on that. This is Swiss chard again and parsley. This might have been that same year where we saw it when it was a little bigger. But that is what it looks like after finishing planting it in and then we just have to harvest. Everything is clean after that you don’t have to whack any of the dirt off of the parsley or weed it. You just go out there and grab a clump without getting weeds with it. There is it when it gets bigger. It is easy to take care of that way. And you see there’s some smaller cucumbers that are coming on and the late tomatoes coming on there. And the next year I might move this whole batch right to here and then do something with more mulch. I’ll just keep working it down the field to constantly be doing more.

Also I like to mulch the garlic in the fall and then in the spring we add a lot more so that we don’t have to weed it. So that we just go in planting it, mulching it, in the spring adding a little more mulch and then just harvesting it. I really don’t really have to do anything else with it. Again, it is another crop we just keep mov-ing around and then in July when it’s all out of there we’ll be turning that under and probably putting in a fall crop. That’s going to be tremendous ground after a week or two of it breaking down. Any crop that you put in there is going to grow the best. We are planting late kale.

Brussels sprouts are going to sit there all year long. We are going to harvest them sometime in October or November. Those are my lower fields right there and, again, once I put down the mulch and I plant it, then I don’t have to go back in again. It’s all set. And it just kind of breaks down as you go along and it actually feeds a little bit of nitrogen down there and the soil is so much better for the next year for anything else you want to grow like beets that are heavy feeders.

——————————

Q: What kind of transplanter are you using?

A: I don’t use a transplanter, I’m doing it all by hand.

Q: How do you make the holes?

A: What we have for prepping the soil is a five-foot rototiller on the back of the tractor. And I’m going along making the soil soft and I know where my rows are going to be so if I’m using that self unloading wagon I’m very careful not to go where I’m going to plant. I make one wheel track down the row where it’s going to go and keep one out. Then I’ll just wad it kind of in the middle and then from there just throw it to either side so it doesn’t take but half a day or so to cover all that ground. So if the ground is really soft then I can easily just put my fingers right into it and make the hole.

——————————

Peppers sit there all year. Another great crop to put in. This is something that you have to watch for. I’m not going to just show you all of the best things that happen to us, I’m going to show you some of the worst so we can all learn here. When you have plastic over the top of straw or you put a row cover over top of the straw this stuff is shiny and when the sun gets on it, it really heats up. It can produce a tremendous amount of heat. Probably if I put a row cover over this and didn’t have this it would be the same effect. It would burn all the plants right up. And if you put your hand in there you would probably burn your hand. It gets so hot. You can’t just go out and put straw down, plant your zuc-chinis and your cucumbers through and throw a row cover over it. If the sun gets on it, it’s going to burn everything up, underneath it. There is something with the shininess, it doesn’t do it with the hay mulch but it will do it with the straw mulch. After we started notic-ing what was going on here, and it took us a little while to figure out what was going on, we thought we had a problem underneath, but it worked out and these are the peppers by late August. They filled in quite nicely. Again, we’ve got clean peppers, we just have to pick them, we don’t have to wash them hardly. It’s kind of nice, there are no weeds in there, nothing. Again you just send somebody out to pick all season long.


Weed Management 91

Here we are, I think this is annual bed strawberries going in. I believe, or it’s the matted row system but we are covering up here. This has already been done before and we are adding more as we go. We’ve got full irrigation so that kind of helps. That kind of gives you what it looks like after throwing all of the mulch down.

Here we are planting winter squash, the rows. All I am doing is putting down a string and somebody is dropping a plant every 18 inches or so. Pretty simple, and as I said you end up with nice clean winter squash when you are done.

Some of the time what we have is these field houses that we do, you can see that I am putting it up in the fall. We’ve thrown down the mulch on it and I can have it ready for the next year for the peppers. We’ll put this up and it will make sure that the ground stays unfrozen and we can start other things in here too or plant anything else I’ve thought about planting, toma-toes or something, early and again it’s no weeding. The ground stays warmer. There it is all finished. We move these around the field also.

Putting down straw mulch or it’s all hay mulch I believe here and were putting down the stakes for tomatoes. Another nice crop to mulch, we don’t have to have any diseases that splash up onto the leaves, like early blight. That’s another good thing to not have to worry about. Much more even with the irrigation. In other words it doesn’t dry out and get wet and dry out and get wet. So you don’t have a lot of cracking when you have some rain.

——————————

Q: So do you drip irrigate that?

A: No, we do overhead irrigation because right next to it could be lettuce growing right here and I can’t stop the water from splashing onto the tomatoes. But that is why we don’t have to worry so much about having diseases splash up because of the mulch being on top. It kind of eliminates that.

Q: Doesn’t the mulch keep the ground too cool and slow the plants down?

A: Not during the summer. Most plants like it warm on top and they like their feet cool. So if their feet get

hot they do not like that too much. The bad part of what you are running into with the straw, especially if you are talking about cucumbers and other things like that, is the fact that if there is a light frost out there, this will not allow that heat from the ground in the fall to keep your plants from frosting so much. These will frost earlier. So you have to be much more diligent with getting row covers on. Realize that if you‘ve got mulch out there you are going to lose the plant faster. Because it doesn’t allow that heat from the ground to come up and maybe save your plants when you are getting really close to 32.

We came across something really interesting this spring, we ended up in our area being one of the very few that had strawberries because of that late May frost. We went out and we were doing the annual bed strawberries and we were doing row covers on them, we were doing triple row covers on them. They started flowering the first week in April and flowered right through until the end of May. We went out one evening around 8:00 or so and it was 41 degrees on our thermometer and we have a digital one so it is pretty accurate and it was 41 and the row covers were start-ing to freeze together. So most farmers probably did not go out and do any row covering or frost irrigation that night till it got much lower but the damage was already long done if you waited much longer than we did. It was already starting to freeze so it is really interesting that when you are talking about mulch or having something high up in the air like that when you get that radiational cooling it’s occurring much earlier than when you think. You can’t wait for it to be 36 or 35 and start up that irrigation. Depending on the sky.

——————————

So they get a little bigger. We have found that now on our ground we cannot plant tomatoes up on these fields were we have been doing this mulch for years because now the ground is so rich that we have toma-toes that come up over the top and then come all of the way down. These are all indeterminate types and the ground has gotten too rich for that because we are doing all of this mulching. We have to put it on some really poor ground. So this has really helped the soil, but it has also changed a few things that we have done.

This is strawberries, this is the matted row system. We don’t do matted row anymore but if people are still doing it I’ll show you what we did with that. When we



plant the strawberries, we will put down the mulch first or put it down afterward because you can kind of drop it on between the plants. We’ll put mulch down after planting the plants and then we don’t have to weed this thing the whole rest of the season. The main question people usually ask is “Well, how do the runners get set down in the mulch? It seems like they are far off of the ground.” Never had a problem. It is always too many runners that set and if a few don’t then fine but this makes matters a whole lot easier than having to weed that whole year. And then in about the first week in November we just go ahead and go in and rototill the rows right down and get it down to where it is the width that you want. We’ll have straw put on for the strawberries and then pull the straw off of the walk paths and then put the row cover on to finish it off un-til they are blooming. So we are adding more organic matter. This is another thing that even though we had matted row we moved it every year. It kind of confused the insects, we did not build up the insect population but we were also using it, again, as the whole farm approach. We knew this was a reason to keep adding more organic matter to our soil. Adding all this nice straw. And then they would look like this when they got up and going. Moving them every year we really didn’t come up with any weeds. And putting down a lot of the straw kept everything clean and again we didn’t have problems with dirty fruit or with weeds. So they came out kind of nice. We got away from this system because of the gray mold problem and because they took up space on the farm all year long and didn’t re-ally pay us back anything. When you are a small farm and you are trying to make use of all your space that seemed like kind of a waste to me. When you have one spot that is costing you money and not giving you back anything. So we went to the annual bed system. So we are preparing ground now in the fall, around the first week in September.

And this is that tractor again and you can just barely see it. I’m sorry for that. Its got two disks here and it is basically like hilling potatoes. I’m building a hill right here and that’s where I’m going to plant the strawber-ries. It’s making two hills at a time. Then we are going along and again it is the first week of September and the grass seeds are not out of the grass. They usually fall down during the season and some hold on a little later so the first week of September it is not clean out there. I can’t just go out and get grass mulch and put it down the first week. I’m putting down straw mulch, just shaking it out. You can see the hills that I have

made and this is where I am going to plant the annual strawberries through. I’m going to cover the whole area, someone is laying them out and I’m going through and just planting them as we are going along. So on each side of that hill we’ve got annual bed strawberries going in. We just plant about 3,000 plants there. Got some free help there. After planting them we put the row covers on them for the fall. They look like that come May first. They are flowering pretty good. Again no weeds, clean fruit, with the annual bed system they are all gone by the first of July. But again we turn this under and made a lot better soil. There is also no gray mold with this system. I’ve never encountered any gray mold and that makes it a lot easier. They also pick about three times faster because you can see them better.

It’s a nice system. Everything is kind of open. There is not one touching another one. They all have got a ring of strawberries around each one. So the picking goes fast.

I also went ahead and we’ve got a lot of flowers around the house and I am mulching that so that we can enjoy the flowers without having to weed them.

Some of the benefits are that we had some investment in buying the equipment, but when we first started out from one year to the next the only thing that we did different was to put mulch down in the fall, turned it under in the spring and then started planting our crops through it. That first few years, when we started farm-ing because the soil did so much better, we found we jumped $10,000 just the first year in gross income. So that more than paid for all of the equipment that we to buy and the time spent putting it on. So there was immediate payback on healthier crops. It really does so much better. It feeds the soil incredibly and some organisms that are there. It brings more of a balance to the soil and everything that happens with it. What also happened was, because this was a cornfield for years and years. I think that it was continuous corn for 30 years. The dairy farmer had a program of so many ton of 15-15-15 every year and never took soil tests. We had an enormous amount of potassium and phosphorus. We found that every year when we were building up that soil and getting more soil organisms in there and a lot more freeing up of a lot of the nu-trients that are there, that our soil tests started going up and up and up tremendously. We’re kind of off the charts for phosphorus and potassium because of what he put on more than 17 years ago. We have yet to use


Weed Management 93

it up, probably it is going to be there a whole lifetime and we will never have to put down phosphorous or potassium.

As I said we are going into more compost now with soil management. Even then as we are using it I’m thinking about going back to more grass mulch because right now if I can control and hold my organic matter at 4-5% or where some of them are a little closer to 6% we can maybe go back to a little more grass mulching and do more with rotation of that rather than buying in compost, where you can bring in weed seeds, you can have problems with phosphorus levels. We are already in trouble with our phosphorus levels. Just one less thing that we have to do.

We don’t use black plastic on our farm because we didn’t want to deal with getting rid of it. There are some things like melons that do much better with black plastic. We choose still not to use it, we still put our melons down on the mulch. Our melons are the last melons to come in for the year. The rest of the farmers, they get them all early in late July and August. Ours come in September and that is fine with us because they are all out of them. It really isn’t a big problem for us.

We don’t do this winter time or fall. We don’t throw mulch down on the fields anymore. We don’t have the help and the time. But when you are first getting go-ing that really helps the organic matter really quickly and helps your plant health. Now we can go though spinach and lettuce and grow it right through the sum-mer because of our organic levels and the amount of nutrients it released.


Any questions?

Q: How do you control the pH? Do you check that?

A: pH was 6.4 when we started and it is still 6.4. It has never changed in 16 years. Not at all.

Q: Are you harvesting the mulch when fresh?

A: Oh! As in green, yes. You are going out and you are chopping it, that is what this flail chopper is doing

it is cutting standing grass. Whether it’s the straw or grass and it will be green. You definitely don’t want to go out there in the early morning when there is a lot of dew on there because it will just plug up the machine.

Q: Do you cut it and let it dry before you put it down?

A: No, not with the grass especially. If it’s heavy in clover, maybe heavy in alfalfa I do go out and do some with alfalfa. That is not so bad when it gets a little older but if you try to do it there is so much nitrogen in there and there is so much water to it that it kind of turns sort of slimy and melts away real fast. It’s gone within a month.

Q: Do you add any nutrients to your hay mulch fields?

A: This is always the thing with organic farmers; we are kind of robbing Peter to pay Paul. Whether or not I’m hauling in compost or doing the hay mulch is that we are always taking from something else and putting it on our most valuable fields. Right now we have gotten into, just this past year; we are going to start fertilizing the fields. We have taken soil tests and we are bringing in organic fertilizers and spreading it on to build the soils back up. We could see a definite drop over these years in the production of these fields because we don’t have the ability to bring in manure and spread it on the fields. So we are going just the fertilizer route at this point. Just putting on a 5-3-4 on it. Our lowest amount is phosphorus and potassium on these fields. In the early years the important thing was to get the vegetables paying, start paying ourselves, and now that we have got some extra money, we are starting to go back to the hay fields and giving them their due. You have to maintain them or else they go downhill real quick over the years.

Q: Do you get 100% weed suppression with the mulch?

A: I wouldn’t say that you are going to get like you have alluded to. You are never going to get a 100% weed suppression with it. For us it is probably 90%. So the little 10% for us that comes through, because it is either breaking down really fast or there is a spot that someone let a transplant go through, a weed came up through because there was exposed light. But it is so minuscule the fact that when you are going down and



harvesting something, you can just pull the weed as you go along as long as it hasn’t gone to seed you can just kind of drop it. But for the most part 90% weed reduction is it. Basically with our weed population, I think you heard me say we don’t allow weeds to go to seed. If I grow carrots, lets say, and I seed them and a week later I start to see them coming up through. Two weeks later you might see in a row 150 feet long or a bed of four 150 feet long you might be able to count 10 weeds in that area. What you mainly see, and I’ll say any other type of weed but you will mainly see for use is purslane because that is what is left is weeds like that, those three weeds galinsoga, purslane and chickweed. If you don’t have them, be diligent that if you see one to get rid of it on your farm or just make sure you are not buying it in. We started getting a little galinsoga and chickweed because we brought in somebody’s compost and it was in the potting soil mix. Wherever we planted it that one year we’ve got little bits of it. We keep a bucket hanging around, so that when we see those two weeds, it doesn’t matter what you are doing, you drop it, go get the bucket and you get rid of that one weed and put it in the bucket and then we just take it off of the farm. So we are trying to control the two weeds. Of course trying to control purslane is bad enough. It comes up and within a week or two or three weeks it can start to set seed. If it is big enough no matter how hot it is, if you go along with your push hoe and cut it off it will live long enough to produce seed and it does not need to go to flower. That’s how we killed ourselves with the fact that, that one weed does not have to go to flower. It can produce, within its bud, viable seed. Only when it feels kind of comfortable and hanging out during the heat of the summer, will you see a yellow flower on it. But for the most part it will never flower and it produces it. We thought in the fall one year when we had a bunch of it, Oh, we are OK because it is not going to go to seed; and then we realized way too late that it doesn’t need to flower. The adaptation of this weed is so tremendous.

Q: Do you have any problems with molds or insects under the mulch?

A: No. The only thing it can do when you say insects. What we had the first few years, because we had quite an imbalance on the farm of not having organic mat-ter and then all of a sudden having a lot of organic matter free flowing around the place, is that you can start to have a problem with slugs. Because there is a

lot of moisture, a lot of nice stuff that they can chew on, a nice habitat. It took a year or two after we really started with that, to start to get some control of the slugs. One was we used some ducks because if you put out grain and put out slugs, a dish of each, they will go for the slugs first. They love them. The other thing that happens is that there is a little black beetle. He is about 1/4 to 1/2 of an inch and you see him scurrying around your farm. That is a lot of their main diet. To eat slug eggs. So all of a sudden with one predator, and it wasn’t like we were trying to go out and kill these slugs because there is nothing you can do about them if they are there, is that these black beetles became abundant. They just went along and brought the balance back in, but we suffered for a year or two of having quite a few slugs. Now nothing is really out of kilter at all with what we are doing.

With molds and stuff like that I don’t think it makes any difference. When you are stepping and walking through it you are not seeing this puff of mold. I want to make sure that is said. Very little bit is mold. It is either in the breakdown period right close to the surface, or it is dry on the very top.

Q: How are you doing your direct seeded crops?

A: Well we are not using any mulch, of course, be-cause that crop goes in and out. For us we are using an Earth-Way precision seeder, the plastic one. We have used the Planet Jr. and we have used the other type and they both have their strengths and weaknesses. When you are doing a lot of different things, a lot of crops that day, and you are putting four types of carrots and three types of beets and stuff like that, you will find that the Planet Jr. can get pretty cumbersome. With changing plates and changing shoes we found with the Earth Way, even though, it seems like such a crude piece of machinery it’s so much faster. You can cut your seeding time down from 3 to 4 hours with a Planet Jr. down to 45 minutes with an Earth Way. So it really makes a difference. Just having to buy in some fertilizers, when you are thinking about how you are going to get your farm up and going and trying to keep your farm together, using just what you have on your farm for your own fertility. When you have hay available, and you can use it then you know you are not importing a lot of stuff that may hurt you eventually with weeds. Some day somebody is going to say something about compost, that it’s got something in it. Using your own mulch and hay can really keep you out of that one


Weed Management 95

problem in your area. The longer you are in business the more these little things pop up.

Q: Have you ever tried using sawdust as a mulch?

A: We only used the sawdust mulch once. That was going to be it because it just took too long for it to break down in a situation where you are changing crops rap-idly. In the end it really made nice soil. In the interim, within a year period, you couldn’t grow anything in it because it was just too much nitrogen uptake by it. You can get by using a little soybean meal as a nitro-gen source. That has 7% nitrogen. That works very nice if you need to put a little bit of nitrogen around the Swiss chard after it has been there a long time to add a little nitrogen. Or if you are turning under this mulch and you are going to plant. For us we would turn under mulch in the spring in the early years and then transplant lettuce right into it. It was a lot of gobs of mulch that hadn’t broken down completely during the winter. By throwing down a little bit of soybean meal on it makes it so that there isn’t that starvation of nitrogen for the lettuce plants while the mulch is breaking down the rest of the way.

I found the list here of what we do, about 15 crops that we mulch. Rhubarb, asparagus, Swiss chard, garlic, winter squash, cukes, melons, eggplant, tomatoes, Brussels sprouts, raspberries, blueberries, parsley, pep-pers and strawberries. We also mulch our basil that we keep all year long. It’s much cleaner. That’s the crops we are working with when we mulch.

Q: How deep are you tilling with your roto-tiller?

A: We are probably going down a good six inches with it. We do it in the spring or sometime during the year we try to get around with our neighbor’s big 4-wheel drive tractor. We put chisel plows on it and if we have got ground that is open or in the early spring we will hit it with chisels to make sure that we don’t end up with plow pans. You know the kind that you get with rototillers or really with a lot of different tillage you can end up with that. That’s about the depth. Very few times we will use it just to go along the surface. But for us, we don’t do any stale seed bedding because most of our weeds are very much under control and I guess it’s an organizational factor. We always seem to be running behind so you are going out there and just tilling the soil and planting right off the bat. There’s a few people out there that are more organized that can

stale seedbed and get things ahead.

We may try a little bit of flaming this year. It was inter-esting just talking about the mulch and using flaming. Because we were thinking about the few escapees that get into asparagus and that is a big thing is the peren-nial type weeds. The fall annuals and perennials that will get in there. It seems they have a long taproot that can get down and below where other ones can’t. We were just kicking that around. Maybe it will be a fire hazard.

Q: Can you talk a little bit about your crop analy-sis. How you set what is making you money and what’s not.

A: For us, we keep just two kinds of records. We keep records to know how much we are making on a per acre basis on each crop so that we can judge whether or not we need to do something with that crop. Do we need to put it closer or not grow it or charge more or something else. We need to know if it is making us money because if we are trying to make enough money on six acres of land than as I have said you have to produce $10,000 to $20,000 an acre to really make any money with this. So we are doing our $10,000 an acre rule which probably should be at least $15,000 at this point. The records we are keeping tell how much space things are taking up. So if I’m putting in four rows of carrots every week for so many weeks I will know how much square footage that is taking up. We will add up the square footage and because we are keeping records on our yield, every time when we are getting ready for market things are getting weighed I can tell you how many pounds of carrots we produce in a year. Then from there we know how much we sell the pound for and we can figure out about how much carrots are making us on a per acre basis. Or how much they have made us on a square foot. Whatever way you want to figure it out it is called extrapolation. So we are keeping that record. That takes two records, yield records and how much space things are taking up. Then we keep records on how long it is taking us to harvest something and how long did it take us to harvest 400 pounds of carrots. We don’t do that every day or every other day. It might take four crops or five crops that season and do a good analysis of those over several weeks. When it’s good or when it’s worse depending on how things are coming out of the ground. So you get a good average. We keep an average of that and that’s how we make decisions on whether or not we need to



invest in a certain piece of equipment that will make harvesting faster or better. That also gives us an idea of how much these crops are worth and helps us all in pricing. Between how much it is costing us to harvest and how much it is worth to have that crop sit on that land are the only two things that we keep track of. We have no idea how much it costs us to raise a carrot. There doesn’t seem to be any reason to know. As you know when you are doing 35 crops that would be an enormous record keeping. To know I push hoed down a row of carrots and then went on to do the beets and then went on … It’s just too much record keeping. That’s basically how we are making decisions on the farm as to what our pricing is going to be and what equipment we are going to buy and how to make things more efficient for our employees or what we are doing or how we are selling a crop. Whether we decide to drop a crop. So the last thing you want to do is drop crops because then you ruin your diversity. If lettuce does terrible next year it really won’t show up on the radar screen. Something else will probably be doing terrific. So keeping a lot of crops out there makes the big difference.

Doing things that control your overhead is also impor-tant. Irrigation for us, we decided to go electric. Electric pumps, and valves. So we can irrigate at the drop of a hat. It takes ten minutes to irrigate. I just go in, throw some valves and throw on a switch and I’m irrigating. Irrigating for me cost $0.48 an hour. So I can irrigate all night for ten hours for $4.80. That’s a lot less for most people than what it costs to run a tractor for an hour. So I have a tendency to irrigate more and when the crops really need it because it is easy to irrigate and also it doesn’t cost me much. So if I want to do some frost irrigation on some raspberries, I only have to sell two half-pints of raspberries to pay for the whole night’s irrigation in October. That’s the record keeping that we keep. So we know whether or not what we are doing is worth while.

Q: Are you doing any cover cropping?

A: What we are doing now for cover cropping is doing winter rye. We are re-seeding a lot of these crops; you saw how much stuff we have at the end of the season. So crops are growing all the way to the end. And with that, winter rye is something that we get on and that’s about the only cover crop that we work a lot with. For the most part we do very little of anything else. What was very interesting last year in

our meeting, you are going to hear a lot more about NEON over the years, North East Organic Network. We participated in that and it was interesting talking because we had a room full of sizes of growers. Some small, some big and what was interesting, we were all accomplished farmers, been in it for a long time and the small growers that were down in my scale, ten acres or less, were very intensive. A lot of them, cover crops, some of them didn’t use any. Some of us were just in the winter rye mode because we were just using every bit of land intensively all of the time. So we are always having these guilt feelings that we should be using a lot more cover crops. We never seem to have time to put them in or the land that you can kind of put stuff on. What we came to realize is that the guys who were bigger, cover cropping was everything for them. They couldn’t afford to buy compost or work things as intensively to make that soil rich. The were working more on the fact of half their land was in cover crops building organic matter to turn under for crops to come because that was the way they had to deal with it. So they were using cover crops more judiciously. Lots of different kinds, different spots they were sticking them in. So it basically took off the guilt feelings of us small farmers. The fact that none of us were doing it. I think its something not to get too worried about, cover cropping when you are really small because you are using that land really intensively. I am getting into this mulching and adding organic matter. That’s what you are really trying to do—you are trying to protect the soil from erosion, trying to keep your nutrients there and trying to improve your soil while you are using it. I think mulching kind of covers that area for me. I don’t have to feel quite so guilty about not having all of this nice perfect cover cropping that everyone really focuses on.

Q: Do you think mulching would work on a larger scale?

A: I think for a lot of crops anything is possible at whatever scale you want to have it at. It just depends on if you have a lot of soil that doesn’t have a lot of organic matter and it is performing poorly you find ways to try and build that soil up and if you really build it with cover crops you are going to be in it for long term. If you are looking to get it into production next year then trying to find some straw mulch that’s good and trying to add organic matter, it’s going to make you money. For us all of a sudden jumping $10,000 from one year to the next was quite a jump.


Weed Management 97

On a larger scale you are just looking at that much more. There is the cost there but that mulch is there and the benefits are there for a few years. It isn’t like the cost is all gone after one year. I think it can really make a difference.

Q: Is it ever a problem for the mulch to get moldy?

A: It’s okay if it does get a little moldy. If you’re put-ting grass mulch over the top of strawberries, some people will think, “Well, I’ve got grass mulch I’ll throw it on top of strawberries for the winter.” It’s going to mat down, turn slimy and get moldy, that’s the worse for it. But just covering the ground, getting a little moldy is okay. It’s not really something that is going to hurt your crop at all.

Q: Are you talking about lawn clippings?

A: I’m talking about hay fields. This is something else you need to learn. If you are going to go out and do that. When does it have seed and when does it not? What we are doing is that we are cutting hay out in the fields right up to the point of the fact that it is going to pollen. Different varieties go to pollen at different times. Like this past year we had this farm nearby, we seeded it to reed canary grass which gets a lot more bulk matter out there and goes to seed much later. I got a bigger window of opportunity of getting it. You are looking for, obviously, the most mass out there. You are look-ing for hay fields that when you are going across them you are getting what you want out of it. Not, like you say with grass clippings where it’s going to take you a long time. Because we’re talking, I’d probably do more like a third of an acre or a half an acre of mulching. If you are putting all of the pieces together and added it up. With that movement around on the six acres, it is every few years that we are really getting a lot of mulch down on an area. We are using it in other ways too, just getting it down. What I’ve noticed for years, is after dealing with the grass mulch is that the soil is actually a lot more alive and a lot more activity than when you are just putting down compost. Compost is something that’s already finished. The mulch needs to break down. That causes a lot of biological activity within the soil. It makes your soil much more alive at that point. This is kind of anecdotal, I realize, but it seemed like the plants grew much better that way as opposed to just putting down compost. Any mulch you are going to hold or add will also not bring down as much phosphorus or potassium as the compost and

you will not have a problem with that. You are also looking at the other benefits of mulching. The fact that it is basically sheet composting because you are build-ing your worm population. You are basically feeding your worms. By putting down all this mulch you are feeding your worms. Obviously that’s going to make more biological activity and you are going to end up with a better soil.

It’s also the weed management. If I’m planting a long term crop that’s going to be there. Like toma-toes and cucumbers and zucchini and stuff. I’m not going to have to weed that the rest of the season. We are putting it down between six and seven inches sometimes more than that. Because as your soil gets more biologically active, we find that lots of times we can’t even make it to the end of the season even at six or seven inches thick. Because there are more worms, more bacteria it’s breaking down at a faster rate. Also it depends on what mulch you’re using. If you are using alfalfa or clovers, it looks great but it can burn up fast. There is not a lot of substance to it like a thick stemmed grass would be. Like we use canary grass. That will stay around longer. Straw will stay around longer. You will have less problems at the end of the season with spots coming through and having some weeds.

You are obviously controlling the water that is there. Some of the downsides are, if it’s really wet it will stay really wet in the spring. Sometimes it doesn’t help with trying to get it broken down or trying to get it turned under at times. It stays sometimes too wet for the crops.

——————————

All right, As I have said we sell at the farmers’ market. You can see all the different array of things that we are doing a lot of different crops, a lot of different op-portunities to put mulch down. This is the last day in November. This is all the different crops that we have that we are selling in the week before Thanksgiving. We are zone four. We are not exactly the warmest spot but we have learned season extension on top of this. This is one of our best days because this is the Saturday before Thanksgiving. That is the biggest sale day of the year, the last day for us. Pretty amazing.

So there’s compost. I’m getting it down. We bought the manure spreader. This one place, H & D, that we



got this from. They actually make spreaders that have different types of beaters on the back. One is made for compost, spreading it more evenly. So that is why we went with this style. We had to get a new one because if you bought old ones they are usually just death worn out by the time somebody traded it in. Cultiva-tors. Wheel hoe. There I am push hoeing. This is the technique of going up and down these rows at a real close spacing. This is where we went to some use of the tractor, using the basket weeders that they were showing. I can go up and down this and this will take me probably 25 minutes or more to go up and down these rows and if I did it with the tractor it would take somewhere in the neighborhood of about four minutes to go up and down twice. Like we showed, going up one side and then going to the other.

This tractor is what we use for a lot of cultivation. It’s got the mid-mount and we’ve got these regular culti-vators on the front, on the mid. After these potatoes go in. This is a potato planter. On the back I’ll carry a Leily tine weeder. That will be the first thing I go over it with after the potatoes are planted is the Leily tine weeder. I’ll go over that at least twice. On the second time I might be cultivating at the same time I’m using the Leily tine weeder. That works. Then for finishing, I’m just using the cultivators. So I can put hillers on the front of these. We can do a lot of cultivation that way.

This is our equipment that is used for getting straw or hay off the fields. This is called a flail chopper. It was used by the dairy industry for a number of years and then, like anything else, they kind of moved on. So these things are a dime a dozen. I think we paid $400 for it. I don’t know how many years ago, twelve, thirteen, fourteen years ago and I’ve probably only put $100 into it. It’s basically, for every foot width this is it takes nine horsepower. So ours is six-foot so it takes fifty-four horsepower. This thing puts out fifty-three so when this is trying to take on too much it’s slowing the tractor down and I know I’m not going to hurt this thing by putting an 80 horse power tractor on it and just kind of ram-rodding through. This is a real good stand of rye that we are putting in and that will really fill the wagon quickly.

This is how we did it in the early years, with just a wagon like that. This is how we built organic matter up really quickly in the first few years. So we could grow spinach or lettuce because we couldn’t grow it even. It

wouldn’t produce on the soil with the organic matter that was there. In the fall we would just go along and just cover the whole ground. No cover cropping just put down on the ground. This was just adding tremendous amounts of organic matter and in the spring we would turn it under.

There we are going down. We are actually putting it in between a field house we are going to put up. This was quite a few years ago but now we’ve got a self-unloading wagon. I’m covering for winter squash, that is what I’m doing. I’m making an area for winter squash to go down so I don’t have to weed it and it just makes for clean fruit and everything else that comes along with it. I’m just kind of going along, blobbing it out, very quick and then somebody is going along and just spreading them the last little bit. This is where we are putting in some late tomatoes here in this area. Putting it right next to Swiss chard and parsley. This was put in real early. This was put in the beginning of May. There is obviously no hay out there to get.

This is where we use some straw. There are times when I cannot get out there and get hay, like in the middle of summer if I need it. Or in the very early spring there isn’t anything out there to chop. This is where we keep straw in the barn in bales that we have bought and we will put it down and then plant through it. You don’t want to go ahead and plant this and then try to put the straw. It just doesn’t work. You’ve got to put the straw down first and then plant right through it. This works very well. Now I don’t have to weed this the rest of the year. It’s much easier on the plants. It’s cooler. All plants like to be warm on top with cool roots. The next year I’m going to have better ground than when I started. This is what the whole farm plan is. The fact of just trying to improve the ground along with doing some intensive planting along the way.

This is buying straw from somebody. Bringing it up. One thing we did try one year just to see if it would work is a bedding chopper that you can get from a dairy farm. They do it in the barn and it is for chopping their bedding. You throw a bale right down in there and it spreads it out. It nicely chops it down, because sometimes working with long pieces of straw is a little difficult. We just had somebody driving along with the tractor and bales of straw sitting on top and went ahead with somebody just throwing it out. By the time we got it all done it looked pretty good and we were able to plant through it. We’ve never tried


Weed Management 99

that again. This was a borrowed piece of equipment just to see if it worked. I think these things are quite a few thousand dollars. So we haven’t gotten into the practice of doing it all the time. But it just gives you ideas if you had that thought, gee this is one way to get the bales out there and chopped up nice. It did put it out nice and even.

——————————

Q: Did the chopped straw control weeds better than the regular straw?

A: Didn’t make any difference. They both control weeds it was just the fact that planting through it was a lot easier.

Q: Why wouldn’t you use the chopped straw all the time?

A: It would be the cost of the machine and the time. I can’t say I figured out how long it would have taken me to put it down by hand. You know just break the bales out and spread it as opposed to doing this. I re-ally didn’t make a cost comparison with that. I knew the machine was more than we really wanted to spend for that little bit that we do with it.

Q: What kind of transplanter did you use to plant through that.

A: We do all of our plantings by hand. We don’t have any transplanter. Whether it’s on bare ground or through that. We are just lining stuff out and putting it through. We don’t own a transplanter. I’m basically the person who transplants.

——————————

This is a little section. We are on a steep slope and we basically wanted anything that was already on this steeper slope to be mulched or in grass. So that is why you see that the orchard is here. We started out, from somebody’s garden they gave us rhubarb. So we started splitting it and splitting it and splitting it and after a few years we ended up with 72 rhubarb plants on a three by three grid here. So every spring or late fall

we go in and put straw on it, mulch it. In 14 years that we have had it we have never weeded it once or done anything other than put straw on it, put row cover on it. We put row cover on it the first of April. Whenever the snow is gone, take it off first of May when we want it to start selling. This was just taken off you can see the dandelions are just flowering. So this is around the first of May and this is what it looks like. As you know I’m from zone four. So it’s pretty rich ground there with having straw for all those years and with the row covers you can have full size rhubarb right off the bat. And again we just go in, we are harvesting it and when we are done harvesting it at the end of May it’s done. We walk away. There is no weeding to be done. There’s nothing. So it makes it kind of nice with rhubarb. When you say, “well when you mulch is it really worth it to do it?” You are sometimes picking crops that you can make a lot of money on. This little rhubarb patch is on 0.0186 of an acre. When you bring it right down to what it is. We sold about 774 lbs., this is back in 1999, with a total value of, I’m trying to think if we sold it for $1.50 a pound or whatever. If somebody has got a quick calculator. $1,161.00 came out of this little patch. If you work that out to what it is worth on an acre basis, because this is where a lot of our crops if they are worth doing, a lot of this mulch bed is ex-trapolating out, that if we had an acre’s worth than this is how much it is worth. This is what we base all of our crops on is the fact that we know the yield because we are keeping records and we are also keeping track of how much we are planting all the time so that we can add up at the end of the year about how much square footage everything took. Then we know the yield and we know how much we sold it for. So you can kind of extrapolate out using that system. Some people do it on square footage. We just happen to do it on acreage basis because in the world of dairy farms and every-body else, they are doing it on a per acre basis. But this little thing is worth $62,000 an acre. This little rhubarb patch. If we are doing not too much work with it and we can spread that a few bales of straw on it. Ten or 15 bales of straw on it really thickly is well worth the money spent on it. That’s where a lot of our crops are well over the $10,000 or $20,000 an acre and with that you can start to make a living at this. But this is how we keep the overhead down and be able to bring some money home. After finding this out it is well worth putting down a few bales of straw on it.



Part One: A Strategy for Weed-Free Onions

Reprinted from Organic Farms, Folks and Foods, the quarterly newsletter of the Northeast Organic Farming Association of New York, Inc., an organization dedicated to the creation of a sustainable regional food system which is eco-logically sound and economically viable. For permission to reproduce more copies contact NOFA-NY at (518) 534-5495. Please include this message in any reprints.

Onions can be a real challenge in terms of weed con-trol because of their slow growth and sparse canopy. Given that our original goals for the farm included remaining debt free, keeping the market garden a two-person-opera tion, and relying on the internal resources of the farm as much as pos sible, we needed a way-to reduce weed pressure in onions that relied more on management than off-farm inputs and that carefully distributed our labor over the course of the growing season. We also decided to lean heavily on the most available resource close at hand, namely the land.

It took us five years to develop the following system, which has kept in-the-row hand weeding of onions well below 15 hours an acre, regardless of the weather. The

rewards for taking time to develop this system were twofold: we could now afford to grow staple, storage items, such as onions, carrots and potatoes; and we could devote more time during the busiest months in the market garden to high value perishables and spe-cialty items for restaurant sales and farmers market.

We begin weed control for onions a full year in ad-vance of planting. This “fallow year” usually includes two winter cover crops sandwiching a bare fallow midsummer. We have tailored this cover crop/fallow sequence to take advantage of the growing-conditions on our farm and the life cycle of the weeds we needed to control.

The cover crop/fallow sequence leads off with rye es-tablished after the previous cash crop in the rotation. If circumstances prevent us from plant ing rye in the fall, then we plant oats the following spring. We manage these small grain covers by clipping them repeatedly before they shoot to head. Mowing them at this time encourages them to tiller and regrow, creating the mulch effect you see in figure 1. This shot captures the second clipping of rye at the end of May 1992. Cut-and come-again cover crop management prevents spring weeds, such as the mustard family, from set-ting seed and makes incorporation of the cover crop easier a than letting the rye grow to its full height of four to- five feet.

Bio-Extensive Approach to Market GardeningAnne and Eric Nordell



Weed Management 101

We plow the first cover crop down after it has put on the bulk of its biomass but before summer weeds have had a chance to set seed. For rye, in our climate, that means after the third clipping at the end of June; for oats, after the second clipping in mid-July. Incorporat-ing these carbonaceous residues during the biologically active summer months gives them plenty of time to break down without robbing nitrogen from the next spring’s crop of onions. This may-seem farfetched, but we think the soil has less “need” to grow weeds when we use these high carbon cover crops and their aggressive root systems to repair the damage done to soil struc ture by the preceding cultivated crop.

More to the point, plowing deeply at this time of year targets perennial weeds at the weakest point in their life cycle. Likewise, harrowing the ground every two to three weeks during the following bare fallow period brings the roots and rhizomes of perennial weeds to the surface to dry in the sun while preventing annual weeds from getting established at a time of year when they are likely to grow quickly and run to seed. As a result of religiously fallow ing our fields every other year this way, quackgrass no longer exists in the mar ket garden and broadleaf weeds like pigweed and lamb’s-quarter are rare visitors. In fact, in recent years we have been able to reduce the bare fallow period to as little as two to three weeks without sacrificing weed control.

However, the transition from very manageable to mini-mal weed pressure was only realized when we began composting the horse manure we use to fertilize the

fields. The composting process kills most weed seeds in the manure and bedding, and the resulting stable soil amendment does not seem to stimulate weed growth in the fields like fresh manures or fast-acting fertilizers. Applying the compost during the fallow year gives it more time to break down before early planted cash crops, saves a step in spring, and enhances the root and top growth of the second soil improving cover crop in this fallow sequence leading up to onions.

The bare fallow ends the first or second week of Au-gust when we seed down the field to the second cover crop. This planting date takes advantage of the fact that most annual weeds which germinate now are likely to frost kill before setting seed here in the mountains of north-central Pennsylvania. Our preference of a cover crop before onions is Canadian field peas because they fix nitrogen, put on a lot of top growth in fall and tend die back over winter.

The big advantage of winterkilled cover crops is that they are so easy to incorporate first thing in spring, making timely planting of onions more dependable. Thanks to winterkilled field peas, we got the 1993 crop in the ground in plenty of time despite receiving two inches of rain every week that spring.

In terms of weed control, an easily incorporated cover crop allows us to restrict tillage to just the top two to three inches of the soil. For example, in figure 2, taken the last week of April 1993, you can see that discing the winterkilled field peas lightly is not as likely to bring

Figure 1Clipping small grain covers repeatedly makes incorporation easier

Figure 2Discing winter-killed field peas lightly in spring brings up fewer weed seeds



new weed seeds to the surface as plowing or rotovat-ing deeply. Keeping the residues near the surface also helps with erosion and moisture control.

Figure 3 shows the 1993 onion crop the middle of June. We had yet to do any in-the-row hand weeding at this time even though the extremely wet conditions extended through May. We usually do plan on cultivat-ing onions three or four times. But because we have been able to reduce weed pressure during the previous fallow year, we target cultivation more for moisture control than weed control. That means getting into the fields as soon as possible after a heavy rain to break the crust and create a mulch of loose soil around the plants to slow evaporation.

Figure 4 shows the onion crop three hot, rainless weeks later. We spent a total of six hours hand weeding this half-acre field by the time harvest was complete the middle of August. By hand weeding, we mean simply walking the field and pulling those few weeds that threaten to go to seed-not a rescue effort to save the crop. Nor is this an attempt to completely clean the field of weeds. Those weeds that manifest themselves later in July or August, such as blown-in dandelions, volunteer clover and a few smartweed, we plan on plowing out after harvest when preparing the field for seeding the winter cover crop and starting the fallow cycle over again.

Keep in mind that a single fallow year is not likely to work miracles. And that the types and timing of cover crops to get this kind of control will depend on your climate, soil and weeds. For example, we can well imagine that the bare fallow period between two winter cover crops might be excessively long in a warmer climate than ours, causing unnecessary damage to soil structure. By the same token, the life cycle and growth habits of winter weeds might require a very different cover crop/fallow sequence than the one we have described for controlling weeks like quackgrass, landcrest, pigweed and lamb’s-quarter.

We learned this firsthand the past two years when we saw chickweed creeping into the field slated for onion production. Based on past experience with isolated patches of this intruder, we were afraid our usual sequence might proliferate rather than control chickweeds since it sets seed well ahead of the normal bare fallow period and is too low growing to control by mowing. So we plowed down the first cover crop pre-

maturely before the chickweed had a chance to reseed. We planted a cover of quick-growing buckwheat the first of June to avoid an extended bare fallow period, and followed the buckwheat with the usual fall cover of winter killed field peas. Both years, this outwitted the chickweed.

To be truthful, some of our time is tied up managing the cover crops and that needs to be figured into the labor equation. As we see it, the total hours devoted to cover crop management are a small fraction of the time spend hand-hoeing an otherwise weedy crop of onions. Besides, we find the fieldwork involved is a welcome balance to all the stoop labor that goes with market gardening. Of more practical importance, this

Figure 3Cultivating three or four times is done mainly for moisture control

Figure 4A half-acre field of onions with only six hours of hand weeding


Weed Management 103

integrated approach to weed management allows us to spread the weed control effort over the course of the growing season to suit our schedule rather than letting the weeds set the pace.

While many growers may feel they cannot afford to idle productive land for weed control alone, bear in mind that the cover crops in the fallow fields serve many purposes. We count on cover crops to help re-store fertility, structure and moisture holding capacity after cultivated cash crops. And we depend on them to minimize erosion, interrupt the cycles of insects and disease and attract beneficials. The beauty of the fallow years is that it gives us the opportunity to use the cover crops to their fullest potential, in this way increasing biodiversity on the farm.

Part Two: A Whole Farm Overview

Reprinted from OEFFA News, which is pub-lished bimonthly as part of the educational mission of the Ohio Ecological Food and Farm Association, a nonprofit organization for farm-ers, gardeners, and citizens interested in eco-logical agriculture and creating a sustainable alternative food system.

“A Strategy for Weed-Free Onions” (part one) de-scribes the cover crop sequence of rye/bare fallow/winter-killed peas we use in the fallow year before EARLY planted cash crops like onions, spring spin-ach, lettuce and snap peas. In the fallow year before LATE planted cash crops like tomatoes, squash, main crop potatoes, or fall greens, we employ a cover crop sequence of clover/bare fallow/rye and vetch. Alter-nating the cash crops between those planted EARLY and LATE sets in motion these two distinct cover crop sequences which help to keep weeds off balance and adds more diversity to the overall farm system.

The four-field photo (figure 5) shows how the cover crop sequences and cash crop rotation work together. For instance, in this shot taken around the fourth of July in 1991 you see:

1. A cover crop of yellow sweet clover in the fallow field to the left, fixing nitrogen and building soil

structure for the next year’s heavy feeding cash crops of…

2. LATE planted mixed vegetables, such as squash, celery, tomatoes, and corn.

3. To the right, winter hardy rye, seeded after the previous year’s LATE planted cash crop, has been plowed down to begin the bare fallow period. We count on the summer fallow, in conjunction with the cover crops, to create weed-free conditions for the next year’s crop of….

4. EARLY planted onions to the far right. To start the rotation over again, we seed the clover right into-or immediately after-these early cash crops so the clover is well established before winter.

By the time we plow down the sweet clover the next July, almost a full year later, the tap roots have tilled and fiberized the soil much deeper than plow depth or the root zone of most market garden crops. If we can use the cover crops to improve soil structure, then the weeds, which often come in to perform this important role, have less reason to grow.

The four-year rotation then repeats itself three times over the twelve-field market garden. We simply sub-

Figure 5Four-field crop rotation

Sweet clover EARLY onionsSummer fallow

LATE-planted mixed vegetables



stitute different cash crops into the EARLY and LATE slots as shown in figure 6 (lower half). Even the depth of tillage can be rotated to the benefit of the crops and discouragement of the weeds.

Of course, the details of the rotation have changed over the years as we adapt to the changes in the climate, marketplace and insect pressure. The principle we keep in mind as we fine tune the system is simply to rotate the types and timing of cover crops in the fallow fields to create the best conditions and control for the cash crop to follow. In this way we have been able to maintain our original objective of substituting land for off-farm inputs and pain labor.

This land-extensive, or bio-extensive, approach to market gardening is much easier to visualize in the slide presentation we had videotaped at the 1996 Penn-sylvania Association for Sustainable Agriculture Con-ference. The 52-minute video also includes segments on designing the market garden with work horses in

Figure 6Rotation of cash crops, cover crops, tillage, and compost applications to enhance weed control, moisture preservation, and soil tilth.

mind, deer control, marketing, and animal-powered composting. Tapes are available for $10 (which in-cludes postage) from Anne and Eric Nordell, RD 1, Box 205, Trout Run, PA 17771.

Rotating the half-acre strips between cash crops and fallow lands is the key to our two-prong weed-control strategyFollowing half of the market garden each year allows us to utilize the bare fallow period midsummer to reduce the weed seed bank in the soil and to realize the full soil structuring potential of the cover crops so that weeds have less need to fill this important role.

SPRING

FALL

rye andvetch

potatoes

rye

cashcrop

root

late

shallow

CROPS

BY TYPE

BY PLANT/HARVEST

TILLAGE

rye

oats &peas

fallow

deep

lettucepeasspinach

clover

cashcrop

leaf

early

shallow

clover

rye &vetch

fallow

deep

fallow fallow fallow fallowcashcrop

cashcrop

cashcrop

cashcrop

deep deep deep deep

shallow shallow shallow shallow

leaf &fruit

late lateearly early

root leaf leaf &flower

rye &vetch

celerykalesquash

rye

rye

oats &peas oats &

peas

rye &vetch

rye &vetch

onions

clover

clover rye &vetch

fallcolesspinachlettuce

oats herbsberriesflowers

clover &mulch

clover& herbs

COMPOST 1. light application (5 tons/acre) in fallow year before root and early crops2. light applications sheet composted with rye and vetch cover crop 6 weeks before late, heavy feeding crops3. light application topdressed on leguminous cover crops

Four-year rotation shown in figure 5 (page 99)


Weed Management 105

First printed in Small Farmer’s Journal, Vol. 17 No. 2

When we settled in northern Pennsylvania 10 years ago, we tilled in the conventional manner of the area, plowing deep with the moldboard plow, repeatedly har-rowing with the spring tooth or disc, then rolling with the cultipacker. The result was a deep, loose seedbed of finely pulverized soil. Under ideal conditions, crops seemed to thrive, but under less than ideal conditions this seedbed had a lot to be desired.

Our third year here the spring winds blew hot and dry, sucking moisture out of the loose topsoil to plow depth. Seeding carrots into six inches of dust was a disaster. Even under less severe conditions we noticed the silty soil on our exposed hilltop site dried to the depth it had been tilled in as little as a week or two without rain, then crusted after the first downpour.

Enough humidity remained in the topsoil to germinate large seeded field crops, like corn or oats, which could quickly put their roots down to moist ground beneath,

A Few Long Furrows on Horsedrawn TillageEric Nordell


Photos by Anne Nordell Beech Grove Farm

Beech Grove, Pennsylvania

Illustration by Edward H. Ochsner II

Skim plow rye and vetch before late cropsRaw organic matter breaks down quickly near the soil surface into homegrown starter fertilizer for the heavy feeding cash crops to follow.

Skim plowA well sodded cover crop is necessary to provide suction for such shallow plowing and to maintain soil structure and capillary action throughout the growing season.



but small seeded root crops and succulent transplants really suffered. Without irrigation, we needed to find some way to hold precious moisture near the soil surface where shallow rooted market crops did most of their growing.

More typically, these mountain soils stayed wet and cool. Deep plowed cover crops and manures decom-posed slowly, if at all. After a damp, cold spring, it was not unusual to dig up raw manure or pieces of still-green rye as late as the end of June. We kind of suspected these pickled animal and green manures may have contributed to incidences of uneven and unbalanced plant growth those first years. Discovering mushrooms sprouted above buried chunks of horse manure reinforced in our minds the idea that what happens below ground often expresses itself above ground as well.

Weed growth seemed to follow the same pattern. We found the clean look of deep plowed fields to be deceiving. Many perennial weeds just seemed to be transplanted by the plow – granted, upside down - only to raise their ugly heads a few weeks later. More to the point, we noticed a sort of delayed reaction with annual weeds. It almost appeared as if their seeds would not germinate until the soil life in the inverted sod had a chance to regroup and eat their fill of raw and rotting organic matter. Inconveniently, that meant weeds came on at the same time the crop did. Pre-plant cultivation for weed control was recreational at best. As if this delayed reaction was not perplexing enough, plowing brought up a whole new batch of weed seeds from down deep, so we never really knew what sort of weeds to expect.

A final concern was conventional tillage did not seem like a good match for our lightweight team. We may have set some speed-plowing records those first years with the Standardbreds, but soft and sassy after a long winter’s rest it almost seemed like deep plowing was more than their minds, if not bodies, could bear. One solution was to work our way up to a somewhat heavier and steadier team of crossbreds. That change only avoided what we thought the Standardbred mares were trying to tell us: Does it really make sense to greet the soil first thing in the spring with the most disruptive and toughest tillage of the year?

When we saw our neighbors park their two bottom plow and hitch nine head to an offset disc you can be

sure that we took notice! They claimed the cornstalks broke down faster when worked into the soil surface, reducing erosion and improving tilth. Well, we just had to put this idea to the test in the market garden. With some good humored help from friends near and far, we had some fun rigging up miniaturized versions of offset discs, chisel plows and field cultivators suitable for a lightweight team.

The machines may not have looked like much, but the results in the fields were impressive. Cover crops and manures decayed quickly when tilled into the soil surface close to the warmth of the sun and the air above. This sort of sheet composting led to more uniform and disease resistant crop growth. And the farm was now mushroom-free.

Since surface tillage did not disrupt the soil life like deep plowing, weed growth became more predictable. Instead of a delayed reaction, annuals germinated readily after surface tilling, making preplant culti-vation a very effective technique. As for shallowly undercut perennials, they simply dried and died in the sun.

Additionally, the ground rarely dried deeper than the shallowly disturbed soil. In fact, the firm earth below maintained capillary action much better than plowed ground, drawing subsoil moisture to the surface where an inch or two mulch of loose topsoil slowed evapora-tion. Where it might take two or more inches of rain to thoroughly re-wet deep plowed ground often only a few tenths of an inch moistened surface tilled soil adequately for seeding or transplanting market crops. Cover crop residues decaying on the surface not only helped to hold moisture, but fiberized our silty soil so it did not wash or crust as badly after heavy rains.

Last but not least, the mares approved of this new technique. Spring tillage was now much easier for these soft and spirited horses. Follow-up passes with the harrow on relatively firm ground were much kinder on man and beast than walking in deep plowed ground. Indeed, surface tillage seemed like a much better way to condition the horses, both psychologically and physically, for the rest of the growing season.

Pleased with our new tools, we intended to use them all the time. We just barely scratched the surface of the farm before planting cash crops, before seeding down cover crops, and before the summer fallow.


Weed Management 107

In short, we surface tilled whenever and wherever we could.

In a few years time, some disadvantages to this single-minded approach began to become clear. To kill and incorporate well-established cover crops, like clover sod or August seeded rye, required repeated trips with our lightweight two-horse equip ment. Sometimes it seemed that in an effort to improve the soil through surface tillage, instead, we were wearing it out. In a wet spring, successfully knocking back these covers was nearly impossible, at least to do so in a timely fashion before early planted cash crops. Likewise, weeds and cover crops during the fallow required many passes with the harrow, disc and field cultivator at a time of year when we were busy enough with the demands of cultivating, picking, packing and marketing veg-etables and herbs. And all of that nice mulchy material on the surface protecting the soil during heavy rains often splashed into the cash crops themselves, making washing lettuce and spinach quite a chore.

Concentrating nutrients and organic matter near the surface with these new tools may not have been such a bad idea in wet years, but crops seemed to suffer doubly in drought conditions as their roots worked their way downward, leaving the dry nutrient zone in search for water. At the same time, that nutrient rich mulch at the surface encouraged weeds to germinate and take hold. Perhaps most surprising of all, after three years of surface tilling some fields became both excessively well drained and firm.

We were not willing to give up on surface tillage alto-gether, but these observations certainly made us think you can do too much of a good thing. That thought then led us to the idea that the benefits of rotating crops might apply to tillage as well. Why not rotate tillage techniques according to the needs of the crops, soil, and seasons of the year?

Practical considerations more or less showed us the way. First off, surface tillage in the spring had proved to be fool proof and effective after winter killed cover crops such as oats and Canadian field peas. Planted late summer, these spring annuals died back at the onset of winter making incorporation and seedbed preparation a snap with just a disc and a harrow before the earliest planted market crops, like spinach, onions and peas. As most of these cash crops were also harvested early in the season, a cover crop of clover could be established

before winter.

Secondly, we had learned that vigorous, winter-hardy covers, such as a mix of rye and hairy vetch, required significantly more time to kill and decompose in the spring than winter-killed cover crops. It just made sense to use rye and vetch before later planted cash crops like tomatoes, celery and fall coles. Rye turned out to be the only cover crop tough enough to establish after these late harvested cash crops.

The trick to making this second crop sequence work was finding an appropriate and efficient way to in-corporate a live cover crop in the spring. We did not want to return to deep plowing given the problems it caused with our soil and crops, but trying to work up a well-sodded cover crop of rye and vetch with our lightweight two horse chisel was a joke. So we tried a compromise approach and plowed as shallowly as we could set the old Leroy walking plow to run. With a little experience, we discovered we could turn a furrow just two to three inches deep. We called this “skim plowing” as the plow just peeled the sod right over, leaving the cover crop residues near the surface and the coarsest portion of the root mass intact below.

We were really pleased with the results. First of all, undercutting the cover crop so close to the surface was sure and sudden death for rye, vetch and volunteer weeds. Secondly, the horses walked along without a hint of hesitation or even breaking a sweat. Most importantly, skim plowed cover crops and manures decomposed quickly at this warm, aerobic and well-protected depth into homegrown starter fertilizer placed at just the right level for the heavy feeding cash crops to follow. Lastly, a pass or two with the spring tooth harrow brought up a good deal of skim plowed top growth and coarse root mass to the surface to help hold and fiberize the soil.

Wow, were we both surprised and encouraged to read this past year of two others advocating skim plow-ing under certain circumstances. We were just naive enough to think we were the only ones to stumble on this technique and crazy enough to actually pursue it. In the Fall 1992 Small Farmer’s Journal, British horse farmer Jeff Peterson writes:

“…What I really like about the moldboard, pulled by horses, is one can bring it down to a fine art and make it a very tidy job, after enough



practice. It is possible to plow very shallow, 3” (7.5 cm) or maybe even less. When I plough I like the organic matter as near to the surface as possible and tidily turned over…”

And from Michael Jost’s Field Advisory File in the Summer 1992 Biodynamics come these comments on improving the sandy soils on Greg and Marley Niewendorp’s Belgian-powered farm:

“…A remark about tilling the soil and good stewardship: There is an advantage of shallow turning (e.g. 2”) of thin layers of soil. Better in two steps than in one. Timing: 2-3 weeks apart, then sow. Plow should not move layers that are not enlivened. The old fashioned horse plow has the advantage that it can indeed be adjusted in such a way that it removes only very thin slices of soil…”

Whether or not skim plowing holds up to the test of time, we think it is exciting and important that farm-ers are putting old tools to new purposes, adapting low horsepower implements to the needs of the land, and proving that new and expensive equipment is not necessary for conscientious soil management.

Here are a few things we learned the hard way about skim plowing: It is essential to work with a well-sodded cover crop for at least two reasons. First off, without deep tillage we are relying on the undisturbed and ex-tensive root system beneath the skim plowed layer to maintain soil structure and capillary action throughout the growing season. In fact, the results seemed much better than after deep plowing. Secondly, a strong sod is absolutely necessary to create suction for such shallow plowing. Likewise, a good share and landside are even more important for skim plowing than conventional deep plowing.

We would not recommend this unorthodox form of plowing for rocky, compacted or unimproved land. Or for beginner teamsters. With the plow planted so lightly in the soil, it seems to have a little more life of its own and may require, at least at first, faster reflexes. To be sure, we are using Leroy in a way for which he was never intended.

Thanks to skim plowing, we now had two reliable crop sequences based on two types of tillage:

1. Surface tilled oats and peas → early cash crops → clover

2. Skim plowed rye and vetch → late cash crops → rye

It did not take us long to realize that we could piece these two crop sequences together by way of the sum-mer fallow into the full blown crop rotation illustrated in the chart (see figure 6, page 100). We were amazed to see how a simple notion like rotating tillage techniques had brought so much more diversity and complexity to the whole farm.

One question remained. How to incorporate full term cover crops before the summer fallow? Chiselling, discing and field cultivating had proved too time-consuming with tools suited for a team. Skim plowing could be difficult if the ground turned hard and dry. And such shallow tillage did not solve the problem of how to deepen the topsoil to create a larger zone of moisture and fertility for shallow rooted market crops to draw on in times of drought. It finally dawned on us that this might be the appropriate place to plow deeply.

We can usually count on these mountain soils to warm up and dry out by the summer solstice. Deep plowing at this time would not be as likely to pickle organic matter, cause compaction or fail to kill perennial weeds as turning wet, cold soil in the spring. Also, there would be plenty of time during the summer fallow to set back a new crop of plowed up annual weeds.

If we were going to plow deeply, we decided we should plow as conscientiously as we could. So we plowed the way Raymond Smoker showed us. Raymond not only taught us how to work horses, but also taught us the love of working horses, a gift for which we will be forever grateful.

Raymond warned that this method of plowing might not win many ribbons at a plowing contest, but that it was the way the walking plow was intended to be used. He simply removed the jointer from the plow and set the clevis to cut a fairly narrow (10-12”) and deep (6-8”) furrow, laying the furrow slice on its side rather than flipping it all the way over. Plowed in this fashion, manures, cover crop residues and the aerobic portion of the soil were not completely buried, but distributed vertically in the good earth. Raymond also pointed out that furrows laid on edge allowed moisture,


Weed Management 109

warmth and air to penetrate the soil easily for quick and proper decomposition of raw organic matter. And he recommended setting the teeth of the harrow deeper with each pass, bringing crop residues to the surface to speed decomposition and slow erosion.

Although Raymond likes nothing better than walking barefoot behind the horses, he made it clear that this style of plowing was not limited to the walking plow. It was possible with sulky plows, gang plows and tractor plows, just so long as the moldboards were not too wide. For example, a trailer plow with four 12” bottoms would work just fine, but a three bottom plow with 16” shares, although turning the same amount of land, would not lay the furrow on edge unless the plows were set excessively deep. Choice of ground speed and moldboard design would also influence the roll of the furrow.

We found vertical furrow plowing to be an ideal way to start the summer fallow because it combined the

best features of conventional moldboard and chisel plowing. Like conventional moldboard plowing, the walking plow adjusted in this manner provided quick and effective weed control while mixing stratified layers of organic matter, minerals and acidity. Like chiselling, vertical furrow plowing loosened the ground deeply without burying all the organic matter and the live portion of the soil. At any rate, it seemed the crops grew better in the following year.

Those Standardbred mares were right! Depth of tillage ought to reflect the natural procession of the seasons, from surface tillage in the spring to deep plowing in the summer months. Although plowing in the heat of the summer can be hard work for horses, the team, already toughened by a few months of fieldwork, took it in stride. The soil also seemed ready, with the earthworms and other soil life now active throughout the whole plow layer, and the cover crop roots so much thicker and deeper than in the spring. Looking from the plow handles, it appeared that the conditioning of the

Skim plowing (left) and vertical furrow plowing (right)Plowing depth matches biological activity of the soil and conditioning of the horses.



soil followed closely the conditioning of the horses.

For more information on the summer fallow, hog composted manure and our neighbors’ offset disc, please see:

• “The Summer Fallow,” Summer, 1991, Small Farmer’s Journal

• “Work Hogs and Horse Manure,” Spring, 1991, Small Farmer’s Journal

• “Alternative Horsedrawn Tillage,” Spring, 1987, Small Farmer’s Journal

Vertical furrow plow, cover crop of clover in fallow year before late crops


Insect and Disease

Management



Insect and Disease Management 113

Organic farmers have long claimed that, on their farms, insect and disease pressure is less than on conventional farms. They believe their emphasis on good soil man-agement and soil quality results in improved plant health and resistance to infection or infestation. Soil quality includes those biological, chemical and physi-cal traits that enhance the ability of a soil to support healthy plant growth (among other things). While there is little conclusive scientific data about the relationship between soil quality and pest suppression, there are several plant and soil interactions may contribute to these phenomena.

Different soil biological, chemical and physical traits have been associated with disease suppression. Many researchers have tried to identify biological indicators for soil health and disease suppression (van Bruggen and Semenov, 2000). However, many of these mea-surements are sensitive to the environment or short-term management effects, minimizing their usefulness. Other researchers have found that soil physical and chemical characteristics can also influence disease levels, including organic matter quality and quantity, pH, calcium, iron, micronutrients, compaction, soil texture, structure, parent material and the predominate clay type, and soil moisture (Hoper and Alabouvette, 1996). The relative importance of any trait varied by the specific disease, and no generalizations could be made for all diseases. In many cases, trying to manipu-late these traits within a soil is impossible (e.g. clay

type). These findings suggest that trying to predict a suppressive soil is nearly impossible, and that focusing on any one trait does not appreciate the complexity of the interactions between soils, microorganisms and plants.

We know that plants can respond to their environ-ment and adapt to some stressful conditions, such as moisture stress or low light levels. Recently, research has found that some of these plant responses are quite instantaneous and suggest that plants are much more active in adapting and responding to the environment than previously believed. Some of these rapid respons-es affect crop susceptibility to pests. These responses are induced by cues from the environment and some of these cues are based upon root interactions with soils and soil microorganisms. To understand how soils affect crop susceptibility to pests, we must consider some these different plant responses and evaluate how they may be optimized to reduce plant losses (Figure 1, page 114). This discussion will:

a. review some of the strategies of pest resistance in plants,

b. soil and rhizosphere effects on this plant resistance, and

c. suggest some strategies to maintain or enhance pest suppression in vegetable systems.

Impacts of Soil Quality on Disease and Insect Resistance in Plants

Anusuya Rangarajan Dept. of Horticulture Cornell University

Ithaca, NY



Plant resistance to pests

Plants may escape damage by pests by associating with other species, developing in times with reduced pest pressure, having some tolerance to the herbivore or confronting the pest with physical or chemical challenges. These physical and chemical challenges to pests include host plant resistance and systemic or induced resistance. Both of these modes of resistance can be affected by plant growth and soil conditions.

Host Plant Resistance

Host Plant Resistance occurs from the expression of plant genes that result in physical or chemical attributes that interfere with the ability of an herbivore (insect, disease or animal) to utilize a plant compared to a plant

not expressing those genes. Common examples of host plant resistance can be found in vegetable varieties that have disease resistance, e.g. tomatoes with resis-tance to verticillium, fusarium and nematodes. These physical or chemical attributes make the plant less appealing or even toxic to pests. Some physical traits that confer host plant resistance include hairiness of leaves (trichomes) or toughness (lignification) of plant parts (e.g. stem solidness in wheat). Hairiness of leaves can reduce ability of sucking insects to land and feed on leaves, and lignification can restrict insect boring into stems or restrict fungal spread into plant tissue. Chemical factors include secondary plant compounds or phytochemicals, such as alkaloids, glucosinolates, terpenoids or polyphenols. These chemicals are the primary mode of host plant resistance and often have very specific effects on pests.

Host Plant Resistance

Plant Health

Induced Resistance

Rhizosphere Organisms

Disease Suppressive Soiland Amendments

Plant Nutrients and Rooting Media

Plant Growth Environment

Figure 1Factors affecting plant resistance in insect and disease pests.



In some cases, these phytochemicals associated with host plant resistance are always present in the plant. In other cases, they are affected by factors, such as plant age, previous plant injury, planting arrangement and crop competition, light levels, ultraviolet radiation, and soil nutrients. Fully expanded, maximally photosynthe-sizing leaves have the highest carbon, nitrogen and wa-ter, and are likely best for herbivores. When leaves age and develop toughness, they often are less nutritious to pests. Previous plant injury by one plant-feeding insect (herbivore) can lead to resistance to other herbivores. Infection by a plant pathogen can change suitability of a host to other pathogens or herbivores for better or worse. Planting arrangement and density can increase or decrease plant stress and subsequent susceptibility by affecting plant health and vigor.

An example of host plant resistance in vegetables is the effect of cucurbitacin in cucurbit leaves on the feeding by cucumber beetle and two-spotted mite. This compound is a powerful feeding stimulant for cucumber beetle but confers resistance to mites. The level of cucurbitacin varies among species and even cultivars of cucurbits. Cucumbers that lack cucurbita-cin are resistant to the beetles but susceptible to mites.

Another example is the production of glycoalkaloids in potatoes. These compounds confer resistance of leaves to the Colorado potato beetle. These glyco-alkaloids in tubers, however, can be toxic to humans. A beetle-resistant cultivar “Lenape” was pulled from the market due to the high levels of glycoalkaloids in the tubers.

Induced Plant Resistance

Induced plant resistance is an enhanced defense capacity developed in a plant after being stimulated (Kuc, 2001). In some ways, this could be described as priming or vaccinating plants—after receiving a “shot” (inducing agent) in a single part of the plant, the whole plant becomes more resistant to future at-tack. Induced resistance does not, however, require application of antibiotics.

This induced resistance is different than host plant resistance in that the effects tend to be non-specific for the target pest. Induced resistance has been described for pathogens in 30 species and for herbivores in 100 species. For diseases, induced resistance is most ef-fective at suppressing fungi, followed by bacteria and

then viruses. For example, anthracnose inoculation of cucumbers provides systemic protection against the same and other fungi, some viruses, wilt fungi and bacteria, but not spider mites or beet armyworm. In cot-ton: spider mites on cotyledons protect against mites, caterpillars, thrips, whiteflies, true bugs and vascular wilt fungi, but not bacterial blight. However, induced resistance will not protect against very aggressive pathogens such as Sclerotina white mold, late blight or some post-harvest rots.

For induced resistance, the plant first must be stimu-lated or challenged (given the “shot”). The challenge may be via an organism (e.g. insect, fungi or bacteria that are pathogenic or nonpathogenic) or a specific chemical (Figure 2, page 116). Induced resistance has been elicited by several different organisms, in-cluding pathogens, insects, plant-growth-promoting rhizobacteria (see below), composts and compost extracts. Several chemicals shown to induce resistance include salicylic acid, potassium phosphate, bicarbon-ate, oxalic acid (spinach or rhubarb extracts), some new chemicals such as Actigard, Bion (salicylic acid mimic), Milsana (giant knotweed extract) or Messen-ger, and some plant hormones (cytokinin and abscisic acid). Thus, the inducer or elicitor is important for what it does, not what the structure is. The modes of action of these different inducing agents are being actively explored by researchers. Interestingly, ap-plication of larger amounts of an inducing agent will not give greater resistance, and the response can vary by cultivars of plants.

Some time must pass after applying an inducing agent before resistance can be observed. The amount of time varies by the species as well as the pathogen. In ad-dition, the inducing agent often needs to be reapplied to keep up the resistance. For example, some of the chemical inducers must be applied every two weeks to maintain the resistance levels (e.g. Messenger). Induced resistance can cause reductions in yield in some cases, but losses to the pest need to be balanced with yield depression.

The potential for induced resistance in agricultural settings seems obvious, but is difficult to document consistent effects. Treatment of crops with inducing agents has shown improved resistance to pests in some cases, but not all. New information on soil microor-ganisms indicates that even root infections can induce resistance in plant tops.



Soil organisms and amendments that affect plant resistance

Plant growth promoting rhizobacteria (PGPR)

The rhizosphere is the 2-5 mm region immediately around plant roots, into which plants pump large amounts of carbon as exudates. Free-living rhizo-sphere organisms survive on plant root exudates and can affect plant growth rate and defend against plant diseases (Whipps 2001). Some of the organ-

isms living in this nutrient rich zone are plant growth promoting rhizobacteria (PGPR) and plant growth promoting fungi (PGPF). PGPR stimulate plant growth and performance under stress in several ways. Some suppress growth of pathogens through a) direct competition for resources or nutrients like iron; b) by predation; or c) by producing antibiotic or antifungal compounds. Fluorescent pseudomonads species are some of the most effective bacteria for suppressing soil borne diseases. Other organisms supply nutrients such as phosphorous or nitrogen, or produce or metabolize plant hormones, affecting crop growth. The types of PGPR often vary by plant

Elicitors of Induced Resistance:Disease and insect pestsPotassium phosphateBicarbonateSpinach/rhubarb extractNew chemical products: Actigard,Sonata, Messenger, Serenade,

CompostsHormones (cytokinin, ABA)

pathogens

Plant Growth PromotingRhizobacteria,

Mycorrhizal fungi

Plant signals that activateinduced resistance

Figure 2Induced resistance requires that the plant be challenged by a pest or by some other compound (elicitor).Once challenged, the crop quickly sends signals to other parts of the plant that cause the plant to enhance resistance, in case of future attacks. The nature of this plant signal will vary by the crop. In some crops, up to two weeks are required after the initial challenge for induced resistance to have an effect.



species and sometimes even variety, making inocula-tion of plants for crop protection challenging. The amount of organisms needed to affect crop growth is unknown.

Sixteen different commonly occurring soil bacteria have been found to induce plant resistance. A link between PGPRs and induced resistance has been re-ported for anthracnose of cucumber, fusarium wilt on carnation and halo blight on beans (Ramamoorthy et al 2001). Mixtures of these PGPRs have been more effec-tive at inducing resistance than application of just one PGPR. These bacteria are applied as seed treatments or drenches to transplants. One interesting interaction has been found between a PGPR and cucurbitacin content of cucumbers. Seed inoculation followed by drenching with a Bacillus species led to reduced cu-curbitacin content in both bitter (high concentration of cucurbitacin) as well as non-bitter cultivars. This consequently reduced feeding by cucumber beetles and reduced transmission of bacterial wilt (Zehnder et al 2001). Thus, a rhizobacteria, growing around the roots affected the expression of a host plant gene, and that in turn affected both insect and disease incidence in the crop. We are only beginning to understand these complex interactions between soil PGPR and the crop’s composition and disease resistance.

Compost and disease suppression

Manure and compost amendments are typically applied to soil to recycle nutrients and build soil organic matter. Composts have also been shown to suppress soil borne diseases and induce resistance in crops (Hoitink and Grebus, 1994). In a study with cucumbers grown in either compost-amended or no-compost media, those grown in compost showed a higher level of induced re-sistance (after being challenged) than those not grown in a compost media (Zhang et al 1998). This indicates that multiple organisms may affect plant resistance (soil organisms as well as above-ground challengers) without causing disease (Figure 2). Microorganisms in compost may also control diseases by competing with the pathogen for food, by producing compounds that kill the pathogen, or by attacking the pathogen directly. Several researchers have explored this type of disease suppression in compost-based media used for ornamentals and food crops. The ability of com-post to suppress diseases has been associated with the composting conditions (food stocks, management), can change with maturity, and can be enhanced through

inoculation with some specific suppressive fungi, such as Trichoderma or Bacillus spp. Not all composts suppress diseases, and some composts may actually increase disease levels. Those high in salts have been shown to increase levels of Pythium, and those not sufficiently cured, especially if they have high nitrogen content, may increase disease.

To maximize benefits of compost in potting media, select well-cured (6 to 12 months) composts. Mix and pot the media before planting, and water to leach any salts out of the media that may inhibit germination and growth. In fields, if the maturity of the product is un-known, apply the compost well in advance of the crop to allow for stabilization of the compost (and reduce nitrogen tie-up) and leaching of any salts.

Strategies to optimize pest suppression through soil management

Organic matter additions to soil become part of a com-plex food web of soil organisms. Regular additions of fresh organic matter (active soil organic matter) will increase microbial activity as it is decomposed by different groups of organisms. In turn, these microbes will affect soil disease suppressiveness, as well as soil physical and chemical characteristics and nutrient availability. Older, more stable organic matter (passive organic matter) is that humus fraction in the soil that contributes to cation exchange capacity and aggregate stability—factors that enhance plant growth.

Since soil organic matter is dynamic, the effect of any particular amendment on soil quality will change over time. Trying to predict the response of various soil microbial functional groups with the addition of any specific amendment is incredibly complex. Compost, while disease suppressive, should be considered only one part of a systems approach to disease management. A good approach is to use repeated (not just single) applications of different types of organic amendments. These amendments will feed different microbes as they are decomposed and increase soil microbial diversity and activity. Evaluate your soil amendments to provide a diversity of food choices to the “soil micro-herd” (Figure 3, page 118). An analogy to the human nutri-tion food guide pyramid could be applied here. Avoid



reliance on any one type of soil amendment, e.g. only rye as a cover crop, to enhance soil health.

Organic agriculture requires use of organic matter amendments to improve soil quality and provide nutrients to growing crops. In one study, field corn was grown (in the greenhouse) in soils collected from organic and conventional farms. European corn borers laid more eggs on plants grown in the conventional soils. The researchers concluded that the overall soil management approach was more important than any specific soil amendments or nutrient levels to predict the insect behavior (Phelan et al, 1995). Other research-

ers have found that in organically managed systems, there is greater diversity in soil biota, higher microbial activity which could contribute to greater competi-tion, antagonism and predation of disease organisms, higher populations of fluorescent pseudomonads and actinomycetes (important biocontrol organisms), and generally a lower incidence of soilborne diseases (van Bruggen, 1995).

There are several components that growers must keep in mind to make full use of the benefits of healthy soil on crop health and pest suppression. First, always strive to optimize plant growth conditions, including

Diversify the Food Choices

Micro-herd Food Triangle

Stable, dead food

New or usedgreen food

Hotfood

Compost, Straw,Leaves, Non-Legume Covers

Grass Clippings,Grain Meals, Greenand Animal Manures

Chemical Fertilizers

Low N AvailabilityHigh C content

Moderate N Availability,Lower C content

High N Availability, No Carbon content

A blend of roots and shoots from different food groups

Figure 3Soil organic matter amendments have different rates of decomposition in soilEach phase of degradation will support different functional groups of soil organisms. The analogy of the food pyramid is helpful to remember to provide different types of soil amendments to encourage a diverse and active population of soil organisms. Prioritize carbon additions to soil, with nitrogen additions (as green or animal manures) that are more moderate, and aim to minimize chemical fertilizers.



minimizing crop stress and competition, and using the best cultural practices for your region. Second, always try to select resistant varieties. Third, provide a diversity of organic matter residues to your soils. These residues, as they are degraded, will enhance microbial diversity and abundance. Some of these microbes will reduce soil pathogens as well as induce resistance in plants, making the plants more able to defend against future pest attacks.

Literature Cited

Hoitink, H.A.J and M.E. Grebus. 1994. Status of biological control of plant disease with composts. Compost Science and Utilization. 2(2):6-12.

H. Hoper and C. Alabouvette. 1996. Importance of physical and chemical soil properties in the suppres-sion of soils to plant diseases. European Journal of Soil Biology. 32(1):41-58.

Kuc, J. 2001. Concepts and direction of induced sys-temic resistance in plants and its application. European Journal of Plant Pathology. 107:7-12.

Ramamoorthy, V., R. Viswanathan, T. Raguchander, V. Prakasam, R. Samiyappan. 2001. Induction of systemic resistance byplant growth promoting rhizo bacteria in

crop plants against pests and diseases. Crop Protec-tion. 20:1-11.

Van Bruggen, A.H.C. 1995. Plant disease severity in high-input compared to reduced input and organic farming systems. Plant Disease. 79(10):976-984.

Van Bruggen, A.H.C and A.M. Semenov. 2000. In search of biological indicators for soil health and disease suppression. Applied Soil Ecology. 15:13-24.

Whipps, J. M. 2001. Microbial interactions and bio-control in the rhizosphere. Journal of Experimental Botany. 52: 487-511.

Zehnder, G.W., J.F. Murphy, E.J. Sikora, and J. W. Kloepper. 2001. Application of rhizobacteria for in-duced resistance. European Journal of Plant Pathology. 107:39-50.

Zhang, W., D.Y Han, W.A Dick, K.R. Davis, H.A.J. Hoitink. 1998. Compost and compost water extract-induced systemic acquired resistance in cucumber and Arabidopsis. Phytopathology. 88(5) p. 450-455.

Zhang,-W.; Dick,-W.A.; Hoitink,-H.A.J. 1996. Com-post-induced systemic acquired resistance in cucumber to Pythium root rot and anthracnose. Phytopathology. 86 (10):1066-1070.



Disease Management Strategies: Cultural Practices

Helene R. Dillard

Professor • Department of Plant Pathology New York State Agricultural Experiment Station • Geneva, New York

Director • Cornell Cooperative Extension

Purchase seed or transplants that are certified disease free.

Select resistant or tolerant varieties.

Consider using hot water seed treatment to reduce con-tamination. Unfortunately, this treatment can reduce germination and vigor in some varieties, and may not eradicate disease from heavily infested lots. It is not a 100% guarantee that the seed will be disease free.

Direct seed when possible. Spread is slower in direct seeded systems. This is basically due to the ability of pathogens to spread among dense plantings found in transplant production areas.

Scout greenhouses and seedbeds on a weekly basis. Look for spots, wilts, or other symptoms characteristic of disease or disorder.

Select sites for seedbeds and crops where rotation has been practiced.

Select sites for disease-prone crops that have good air flow and good soil structure that promotes drainage.

Raise transplant beds above the surrounding area or trench the periphery to provide for drainage of excess rainfall. Flooding of the seedbed area can result in widespread infection.

Plant several smaller transplant beds rather than fewer large transplant beds. With smaller transplant beds, individual seed lots from different sources can be isolated from each other. Then, if one seed lot has an undesirable disease, you can destroy plants in that lot in order to prevent spread to the remainder of your plants.

Keep varieties separated in the greenhouse and in seedbeds. Pathogens and especially bacteria are rapidly spread in water; close spacing in seedbeds and in the greenhouse is ideal for rapid disease development. Keeping the varieties separate will help you identify problematic varieties.

Destroy volunteer plants and weeds growing in and near the transplant bed and production fields. These plants may harbor pathogens. Symptoms on weed species may or may not be present.

Destroy all remaining plants in a seedbed as soon as transplanting operations are completed. Transplants should only be handled when the foliage is dry.

Do not dip or water transplants in crates or boxes—this will very effectively spread pathogens.

Some bacterial diseases are highly contagious. For example, if black rot is detected in a seedbed consider all plants at the location to be contaminated. Do not attempt to separate healthy from diseased plants. Many



plants will be contaminated, but will not be showing symptoms until the environmental conditions are fa-vorable for symptom development.

Do not plant transplants showing disease symptoms. These plants will continue to be problematic through-out the growing season.

Insects should be controlled because insect feeding injury provides wounds that are a large target of op-portunity for infection.

Only new crates should be used for shipping trans-plants. Reusable plastic or wooden plant containers brought to the field should be cleaned and disinfested before returning them to the seedbed area for reuse.

Clean all transplanting equipment before and after each use.

A well-balanced nutrient program will suppress disease development. For example, studies have shown that excess nitrogen causes lush vegetative growth and can make crucifers more susceptible to black rot. Results from a recent study showed that boron applied alone or with nitrogen reduced the disease severity of black rot in cabbage.

Avoid using overhead irrigation, but if necessary ir-rigate during the time of day when the plants will dry quickly.

Contaminated equipment, people, animals, overhead irrigation, and wind-driven rain will spread patho-gens. Always work in diseased fields last and restrict activities in fields until later in the day when plants are completely dry to reduce the potential spread of the disease.

Tools used for pruning, staking, and tying should be disinfested frequently, and especially when used on different varieties. Wounding plants during these op-erations should be avoided, as wounds provide a site for entry of pathogens.

Planting on raised beds allows excess water to drain from around plant foliage and roots. Removal of exces-sive moisture is a deterrent to disease development.

Mulching has been shown to provide a physical bar-rier between susceptible plant tissue and overwinter-

ing inoculum of pathogens. When disease pressure is not severe, mulching can provide as good control as conventional chemicals.

Achieve good weed and insect control. Weeds may harbor pathogens, rob the soil of valuable nutrients, and encourage moisture retention in the canopy that is favorable for disease development. Insects may serve as vectors for pathogens and/or their feeding injury may provide a site of entry for pathogens.

Plant residues should be incorporated after harvest to encourage breakdown of diseased tissues.

Cover crops and compost should incorporated into soil. Both have been shown to build overall soil health and promote buildup of beneficial microorganisms.

Various natural teas have been shown to provide disease suppression in specific pathogen systems. In general, compost teas hold the most promise for pro-moting, plant health and suppressing buildup of patho-gens. Excellent information was recently published by the Organic Farming Research Foundation in the Winter 2001 number 9 information bulletin. Compost teas are very complex and require precise handling to produce efficacious teas.

Cull piles with infested debris should not be dumped on fields scheduled to grow the same crop the following year. Research conducted in the Netherlands has shown that fresh infested cull piles are a significant source of pathogenic bacteria that resulted in the development of a black rot epidemic.

Rotation to a non host crop is always recommended.

Helpful Disease Management References

Sustainable Vegetable Production From Start-Up to Market. Vernon P. Grubinger. NRAES-104, ISBN 0 935817 45 X

Plant Disease Control; towards environmentally ac-ceptable methods. Richard N. Strange. Chapman and Hall, 1993, ISBN 0 442 31666 6



Alternative Agriculture. National Research Council. National Academy Press, Washington, DC 1989, ISBN 0 309 03987 8

The Real Dirt. Edited by Miranda Smith and members of NOFA. 1994, NESARE

Plant Diseases: their biology and social impact. Gail L. Schumann. 1991 APS Press, ISBN 0 89054 116 7

Compost Tea Manual. Karl Rubenberger, 1999. Avail-able from Organic Farming Research Foundation

Web site for info on soil health, etc. Soil Food Web Incorporated. Dr. Elaine Ingham. http://www. soil-foodweb.com/sfi_html/ezine/index.html

Biocontrol Products, Manufacturer, Active Ingredient

• Mycostop, Kemira Agro Oy, Streptomyces griseo-viridis strain K61

• RootShield and PlantShield, Bioworks, Tricho-derma harzianum Rifai strain KRL-AG2

• Aspire, Ecogen, Candida oleophiia isolate 1-182

• Serenade (QRD 137), AgraQuest, Bacillus subtilis QST 713 strain

• SoilGard 12G, Thermo Trilogy, Gliocladium virens GL-21

• AQ10, Ecogen, Ampelomyces quisqualis

• Contans, Encore Technologies, Coniothyrium minitans

Products from organic origins, Manufacturer, Active Ingredient

• Elexa, Safe Science, chitosan

• Trilogy, Thermo Trilogy, clarified hydrophobic extract of neem oil

• Milsana (a.k.a. BAS 114 UBF and KHHUBF- 99-001), KHH BioSci, Reynoutria sachalinensis (giant knotweed) extract



Resources for Disease and Pest Management

Northeast IPM Web site: http://northeastipm.org/

New York Resources

http://www.nysipm.cornell.edu/

1. A Growers’ Guide to Cabbage Pest Management in New York

2. Snap Bean Pest Management: A guide to regular field monitoring in New York (manual and video)

3. Integrated Pest Management for Onions (manual and video)

4. Integrated Crop and Pest Management Guidelines for Commercial Vegetable Production

http://www.nysaes.cornell.edu/recommends/

5. Fresh Market Sweet Corn Scouting Procedures

http://www.nysipm.cornell.edu/scouting/scout-proc/fmsc99.html

6. Processing Sweet Corn Scouting Procedures

http://www.nysipm.cornell.edu/scouting/scout-proc/prswcorn99.html

7. Cucurbit Scouting Procedures

http://www.nysipm.cornell.edu/scouting/scout-proc/cuke00.html

8. Tomato Scouting Procedures

http://www.nysipm.cornell.edu/scouting/scout-proc/tom00.html

9. IPM Elements

http://www.nysipm.cornell.edu/elements/index.html

10. Hoffmann, M and A. Frodsham, 1993. Natural Enemies of Vegetable Insect Pests. CCE

11. Biological Control: A Guide to Natural Enemies in North America

http://www.nysaes.cornell.edu/ent/biocontrol/index.html

Cultural Practices for Disease ManagementCurtis Petzoldt

Vegetable IPM Coordinator Integrated Pest Management Program

New York State Agricultural Experiment Station Geneva, New York



NewYorkContacts

C. Petzoldt

A. Seaman

J. Mishanec

Massachusetts Resources

http://www.umass.edu/umext/programs/agro/ipm/

1. General vegetable page with many links

http://www.umassvegetable.org/

2. Specific crop page with scouting procedures for many crops including: Crucifers, Cucurbits, Herbs, Hydroponics, Legumes, Lettuce and Greens, Pep-pers, Potatoes, Specialty Crops, Root Crops, Sweet Corn, Tomatoes

http://www.umassvegetable.org/soil_crop_ pest_mgt/specific_crops.html

MassachusettsContact

Ruth V. HazzardPhone: (413) 545-3696E-mail: [email protected]

Maine Resources

http://www.umext.maine.edu/topics/pest.htm

1. Potato IPM page

http://pmo.umext.maine.edu/potatoes/potato.htm

2. Broccoli IPM page

http://pmo.umext.maine.edu/broccoli/broccoli. htm

3. Sweet Corn IPM page

http://pmo.umext.maine.edu/swetcorn/corn.htm

MaineContact

Jim DillPhone: (207) 581-3880E-mail: [email protected]

New Jersey Resources

http://pestmanagement.rutgers.edu/

1. Web page has link set up for scouting procedure location but they are not currently present

2. Web page includes IPM Elements for several vegetable crops

http://pestmanagement.rutgers.edu/

NewJerseyContact

Joe Ingerson-MaharPhone: (732) 932-9802E-mail: [email protected]

Connecticut Resources

http://www.hort.uconn.edu/ipm/ipmprog.htm

1. Vegetable IPM information and fact sheets for pep-pers, tomatoes, beans, cole crops, corn, cucurbits, lettuce, potatoes, eggplant and squash

http://www.hort.uconn.edu/ipm/ipmveg.htm

ConnecticutContact

T. Jude BoucherPhone: (860) 875-3331E-mail: [email protected]

Delaware Resources

http://www.udel.edu/ipm/

1. Sampling Guidelines and action thresholds for Cabbage, muskmelons, potatoes, sweet corn, wa-termelons

http://www.udel.edu/ipm/thresh_index.html



2. Insect trap catches and disease forecasts plus other reference publications

http://www.udel.edu/ipm/

DelawareContact

Joanne WhalenPhone: (302) 831-1303E-mail: [email protected]

Rhode Island Resources

http://northeastipm.org/states/ri/index.html

IPM page does not currently contain much specific vegetable scouting information.

RhodeIslandContact

Richard A. CasagrandePhone: (401) 8742924E-mail: [email protected]

Vermont Resources

http://northeastipm.org/states/ri/index.html


http://pss.uvm.edu/ipm/small.htm

VermontContact

Ann HazelriggPhone: (802) 656-0493E-mail: [email protected]

West Virginia Resources

http://www.wvu.edu/~agexten/ipm/


WestVirginiaContact

Rakesh S. Chandran.Phone: (304) 293-6131 Ext. 4225

Maryland Resources

http://www.agnr.umd.edu/users/nrsl/entm/

IPM page does not currently contain much specific vegetable information.

MarylandContact

Sandra SardanelliPhone: (301) 405-7877E-mail: [email protected]

New Hampshire Resources

http://ceinfo.unh.edu/agriculture/documents/agipm.htm

IPM page does not currently contain much specific vegetable information.

NewHampshireContact

Dr. Alan T. EatonPhone: (603) 862-1734E-mail: [email protected]

Pennsylvania Resources

http://paipm.cas.psu.edu/


http://paipm.cas.psu.edu/cguides.html

PennsylvaniaContact

Dr. Ed RajottePhone: (814) 863-4641E-mail: [email protected]



Regional/U.S. References

Peppers

Boucher, T. Jude and Richard Ashley. 2000 Northeast Pepper IPM Manual. University of Connecticut, Com-munications and Information Technology, 1376 Storrs Rd., U-4035 Storrs, CT 06269-4035. $19.95

Potatoes

Western Regional IPM Project. 1986. Integrated Pet Management for Potatoes in the Western US. Univer-sity of California Publication 3316.

Hollingsworth, Craig S, David Ferro, and William Coli. 1986. Potato Production in the Northeast: A Guide to Integrated Pest Management. Massachusetts Coopera-tive Extension Publication C-178.

Rowe, Randall C. 1993. Potato Health Management. APS Press. 3340 Pilot Knob Road, St. Paul, Minne-sota. 55121.

Hooker, W.J. 1981. Compendium of Potato Diseases. APS Press. 3340 Pilot Knob Road, St. Paul, Minne-sota. 55121.

Cucurbits

Motes, Jim and Gerrit Cuperus. 199?. Cucurbit Pro-duction and Pest Management. Oklahoma Cooperative Extension Service Circular E-853.

Bernhardt, Elizabeth, Jeff Dodson, John Watterson. 1988. Cucurbit Diseases: A practical Guide for Seedsmen, Growers, and Agricultural Advisors. PetoSeed.

Zitter, Thomas, Donald Hopkins, and Claude Thomas. 1996. Compendium of Cucurbit Diseases. APS Press. 3340 Pilot Knob Road, St. Paul, Minnesota. 55121.

Onions

Schwartz, Howard F. and S. Krishna Mohan. 1995. APS Press. 3340 Pilot Knob Road, St. Paul, Minne-sota. 55121.

Crucifers

University of California IPM program. 1985. Inte-grated Pest Management for Cole Crops and Lettuce. UC Publication 3307.

Schooley, Jan. 1995. Integrated Pest Management for Crucifers in Ontario: A Handbook for Growers, Scouts and Consultants. OMAFRA

Cucuzza, James, J. Dodson, B. Gabor, J. Jiang, J. Kao, D. Randleas, V. Stravato, and J. Watterson. 199?. Crucifer Diseases: A Practical Guide for Seedsmen, Growers, and Agricultural Advisors. PetoSeed.

Sweet Corn

Adams, Roger and Jennifer Clark. 1995. Northeast Sweet Corn Production and Integrated Pest Manage-ment Manual. University of Connecticut Cooperative Extension.

Shurtleff, Malcolm. 1980. Compendium of Corn Diseases. APS Press. 3340 Pilot Knob Road, St. Paul, Minnesota. 55121.

Blair, B.D. et al. 198?. Corn Pest Management for the Midwest. North Central Regional Publication No. 98.

Tomatoes

University of California IPM Program. 1985. Inte-grated Pest Management for Tomatoes. UC Publica-tion 3274.

Jones, J.B., John Paul Jones, R.E. Stall, T.A. Zitter. 1991. Compendium of Tomato Diseases. APS Press. 3340 Pilot Knob Road, St. Paul, Minnesota. 55121.

Pernezny, K et al. 1995. Florida Tomato Scouting Guide. University of Florida Publication SP-22

IPM, Organic, and Sustainable Agriculture

Appropriate Technology Transfer for Rural Areas

http://www.attra.org/



Table 1Cultural Practices for Controlling Plant Diseases

Practice Conditions Affected Disease Prevented

Use resistant varietiesManage vectors of diseases

Slows or stops disease development Many diseases

Staking, pruningWide-row spacing

Increase air movementand leaf drying

Many foliar diseases

Timely irrigationUse drip instead of sprinkler irrigation

Minimize leaf wetness periodSlows or stops disease development


Rogue or destroy infected plants Slows or stops disease development Many diseasesWindbreaks Limit spread of airborne spores Many foliar diseases

Plastic or straw mulchesDo not work in fields with wet foliage

Prevent soil splashing onto foliage, fruitReduce spread of inoculum


Raised bedsChisel plow or subsoiling

Improve water drainage Many root and crown rots

Careful cultivation Promote healthy root growth Many root and crown rots

Floating row coversReflective mulches

Reduce aphid (vector) feeding Many viruses

Use disease free seed or transplantsPhysically separate plantings

Reduce source of inoculum Many diseases

Good weed control-on farm Reduce source of inoculum Many virusesGentle harvest methods Avoid cuts, bruises Postharvest diseases

Rapid cooling at harvestStore at cool temperatures

Slow microbial activity Postharvest diseases

Optimize NPK fertility Reduce stress, avoid rank growth Diseases in general

Rotate cropsIncorporate crop residuesRemove infected crop debris

Reduce inoculum buildup Diseases in general

Wash equipment frequently Reduce spread of inoculum Diseases in general

C. Petzoldt adapted from H. Dillard



Insect and mite pests plague vegetable farmers, caus-ing damage to almost all crops. Many tactics are available to manage insect pests and the integrated pest management (IPM) strategy encompasses them all. Integrated pest management is fundamentally the same as organic pest management except in organic systems there may exist more long-term stability or balance in the overall system for a number of reasons including a more diversified farming system. The two approaches also differ when it comes to the use of pesticides. If pesticides are used in organic farming the options are limited to a relatively few “natural” products. In contrast, the conventional farmer has a multitude of synthetic and natural compounds to use. Like organic pest management, IPM is ecologically based and promotes pest control tactics such as pest-resistant plants, and cultural, mechanical, physical and biological control methods. Regardless, all farmers want to produce safe food with minimal risks to health and the environment.

One pest management tactic that is common to all veg-etable farms and is generally free is biological control. All insect pests have natural enemies. These organ-isms may be predators, parasitoids or disease-causing pathogens. The use of these organisms to manage pests is known as biological control. The emphasis here is on the biological control of insects, though biological control is also very important for the control of weeds and plant diseases.

Predators

Predators such as lady beetles and lacewings, are mainly free-living species that consume a large num-ber of prey during their lifetime. They include many beetle, bug, fly, mite, and spider species. Both adults and immatures are relatively mobile and search for prey. In some species such as lady beetles, both the larvae and the adults feed upon prey. In others, such as syrphid flies or lacewings, only the larvae consume insect prey. The adults may obtain nourishment by feeding on nectar or pollen. Examples of some com-mon predators include:

Lady beetles

Adult lady beetles are small, round to oval, and dome-shaped and live for a few months to over a year. Lady beetle larvae are dark and alligator-like with three pairs of prominent legs. Both adults and larvae are predacious. Lady beetles overwinter as adults, often in aggregations along hedgerows, beneath leaf litter, under rocks and bark, and in other protected places including buildings. In spring, the adults disperse in search of prey and suitable egg laying sites.

Female lady beetles may lay from 200 to more than 1,000 eggs over a one to three month period, commenc-ing in spring or early summer. Eggs are usually depos-

Identifying and Encouraging Beneficial InsectsMichael P. Hoffmann

NYS IPM Program and Department of Entomology Cornell University Ithaca, NY 14853



ited near prey such as aphids, often in small clusters in protected sites on leaves and stems. The more common species typically have one to two generations per year.

Most lady beetles found in vegetable crops and gardens are aphid predators. Some species prefer certain aphid species while others will attack several species on a variety of crops. If aphids are scarce, lady beetle adults and larvae may feed on the eggs of moths and beetles, and mites, thrips, and other small insects, as well as pollen and nectar. They may also be cannibalistic. Because of their ability to survive on other prey when aphids are in short supply, lady beetles are particularly valuable natural enemies.

Lady beetles are voracious feeders and may be numer-ous where prey are plentiful. Lady beetles need to eat many aphids per day so that they can lay eggs. The convergent lady beetle may eat its weight in aphids every day as a larva and consume as many as 50 aphids per day as an adult. Sevenspotted lady beetle adults may consume several hundred aphids per day and each larva eats 200 to 300 aphids as it grows.

Green lacewings

The common green lacewing is native to much of North America. Adults feed only on nectar and aphid honeydew, but their larvae are active predators. Adult green lacewings are pale to bright green, about ~1/2 to 3/4” long, with long antennae. Large, transparent wings are held upright over a fragile body. Some species have prominent, golden eyes. Adults are ac-tive fliers, particularly during the evening and night. Through spring and summer, the female lays several hundred small eggs, each at the end of a long silk stalk, sometimes in clusters, on leaves or twigs in the vicinity of aphids. The larvae are pinkish brown and cream, and alligator-like with well-developed legs and large, prominent pincer jaws, used to suck the juices from prey. They are very mobile and grow through three instars, in about two to three weeks.

Reported prey include several species of aphids; thrips; mites; whiteflies; eggs of leafhoppers, moths, including diamondback moth, cabbage looper, and corn earworm, Colorado potato beetle, asparagus beetle, and, possibly, leafminers; small caterpillars and beetle larvae, including small larvae of Colorado potato beetle.

Lacewing larvae are generalist beneficials but are best known as aphid predators. The larvae are sometimes called aphid lions. Various reports suggest that de-veloping lacewing larvae eat from 100 to 600 aphids. Larvae and adults may be common in sweet corn and field crops through summer.

Hover or syrphid flies

Adult hover flies resemble bees or wasps and are usually seen on or near flowers. The male flies have a distinctive hovering and darting habit. Hover flies range in size from quite small to a little larger and narrower than houseflies. The female hover fly lays single elongated eggs near or among aphid infestations. Females may lay several hundred eggs through mid-summer; the larvae hatch after two to three days. The small, cylindrical, legless maggots vary in color from cream to green to brown, depending on the species and prey consumed. They develop a “slug-like” form, up to ~1/2” long, tapered towards the head. The larvae can move around leaves and through the canopy in search of prey. The period from egg to adult ranges from two to six weeks, depending on the temperature, species, and availability of aphids. If aphids are plentiful, there may be five to seven generations per year.

Hover flies larvae feed on aphids, small caterpillars, and, possibly, thrips. Hover fly larvae have been re-corded as predators of the larvae of European corn borer and corn earworm. In vegetable crops hover fly larvae may be most apparent from mid-summer to fall. This may be after the initial aphid infestation has established, depending on the crop, species, and region. Hover fly larvae are voracious aphid predators. A single larva may consume up to 400 aphids during develop-ment, depending on species of hover fly and aphid.

Bats

These natural predators are often overlooked as pos-sible biological control agents. One reason is the dif-ficulty in proving that they actually reduce pest infesta-tions. However piecing together the existing informa-tion and knowing that they consume large numbers of insects strongly implies that they do provide farmers some benefit. Another point to bear in mind is that bats feed at night in contrast to most beneficial insects, which seek prey during the day. Thus bats complement the benefits derived from insect natural enemies. The reason not much is known about the potential benefit



derived from bats and birds is that they prey mostly on highly mobile adult insects and the impact on this stage has been exceedingly difficult to study.

The bats common to central New York include the little brown bat (Myotis lucifugus), big brown bats (Eptesicus fuscus), hoary bats (Lasiurus cinereus) and red bats (Lasiurus borealis). Little brown bats can eat up to 1200 mosquito sized insects in an hour. Big brown bats consume insects at a rate of 500 per hour. Bats are free to farmers and there are no environmental side effects associated with their use.

Parasitoids

Parasitoids are species which have an immature stage that develops on or within a single insect host, ultimately killing the host. The adult parasitoid lays her eggs on, within, or near the host. The immature parasitoids, which hatch from the eggs, are entirely dependent on their host for nourishment. They feed (internally or externally) on the host, developing to maturity and eventually leaving the host as adults or to complete development. Adult parasitoids may be predatory or they may seek other food sources. Many species of wasps and some flies are beneficial parasit-oids. Examples include:

Aphid parasitoids

Aphidiid wasps attack only aphids. Adults are very small (~1/8”) and dark, with long antennae. Typically, females lay up to several hundred eggs. One larva de-velops within each aphid. The larva either emerges to spin a cocoon under the dead aphid or pupates within the tanned and mummified aphid body. The adult wasp emerges after cutting a circular hole in its cocoon. Adults live from one to three weeks, and there can be many generations per year. Some species overwinter within the mummified aphid host.

The most conspicuous sign of aphidiid activity is the presence of aphid “mummies.” The mummies may oc-cur within an aphid colony or be found singly on leaves or stems. Praon species spin their cocoon beneath the aphid body to encase the developing parasitoid pupa. Most aphid species will be parasitized to some extent if aphidiid wasps are present. Different wasp species may parasitize different aphid species.

Egg parasitoids

Trichogramma species are egg parasitoids with a very wide host range, especially among the moths. Several species have been mass reared for use in biological control programs. The adult wasps are minute, mostly 1/50” long. The female wasp lays one or more eggs in an egg of the host insect, and one or several parasitoids may develop. Trichogramma species pupate within the host egg. Adult wasps emerge seven to 10 days after the egg is deposited. Warm temperatures favor development and many generations may be produced each season. Trichogramma overwinter in the host egg, emerging as adults the following spring. Eggs usually turn black as the parasitoids develop inside. A small hole in the black host egg indicates that the wasps have emerged. Reported hosts include eggs of caterpillar (worm) pests such as European corn borer, corn ear-worm, imported cabbageworm, diamondback moth, cabbage looper, and tomato and tobacco hornworm. Trichogramma are particularly good natural enemies of caterpillars because they parasitize and kill the pest in the egg stage, before the crop is damaged.

Worldwide, no other group of parasitoids has been used as extensively as the Trichogramma for direct control of pests, and considerable effort has gone into the mass rearing and release technology. Experimen-tal or commercial biological control programs with Tricho gramma have been undertaken or are available for control of pests of corn, cotton, cabbage, pea, avo-cado, tomato, forests, soybean, rice, and citrus. The successful use of commercially reared Trichogramma requires that the correct species be used, that it be of high quality, and that the parasitoid be released at the appropriate rate and when the host eggs are present. Us-ers should follow directions very carefully and examine the release units before, and several days after, placing them in the field to see if the material is viable and to determine if the Trichogramma actually emerged (exit holes should be present in each egg). To determine if the releases are providing some control, pest eggs can be collected at the release site and observed for para-sitism. Note, however, that naturally occurring (not released) Trichogramma may also be present.

Tachinid flies

Adult tachinid flies are often gray, reddish, or yel-lowish-brown, heavily bristled (or fuzzy), and about 3/8 to 1/2” long. Some tachinid flies resemble large,



bristly house flies. Females may place their small eggs directly on their host. Some species inject living larvae directly into the host; others lay eggs or larvae on a leaf surface where they can be eaten by the host, or at the entrance of a host cavity or feeding tunnel from where the larvae seek the host.

The larvae or maggots are grayish or greenish-white; they may have thick bodies with tiny spines or even plates. Usually only one larva survives per host. The larvae of many tachinid species bore out of the host to pupate, often in the soil. The time spent as larvae or pupae can be days or months, depending on the species. Tachinids overwinter as larvae or pupae within the host body. There may be one or several generations each season. Tachinid adults searching for hosts may walk rapidly over leaf or soil surfaces, moving in hops and small flights around their target. Caterpillars and beetle larvae become extremely agitated in their efforts to fend off attack by a fly and will attempt to remove the eggs from their body. Reported Tachinid hosts include larvae of European corn borer, corn earworm, imported cabbageworm, cabbage looper, potato stem borer, stalk borer, cutworms, armyworms, Mexican bean beetle, and Colorado potato beetle; stink bug and squash bug nymphs and adults; and adult tarnished plant bugs and cucumber beetles.

Immature insects parasitized by tachinids and other parasitoid flies invariably die. Parasitized adults may continue to lay eggs before succumbing but parasitized hosts are generally less able to survive environmental stresses and consequently their lifespan is shorter than unparasitized individuals. Some adult tachinids also feed on pest insects. Tachinid populations can increase very quickly and their high fecundity and relatively short life cycle give them a competitive edge over many of their hosts.

Pathogens

Pathogens are disease-causing organisms including bacteria, fungi, viruses and nematodes. They kill or debilitate their host and are relatively specific to certain insect groups. Their effectiveness can be dependent on environmental conditions such as humidity and frequently they are most effective when the susceptible insect species occurs at high densities (crowded con-

ditions). Under the correct environmental conditions, certain diseases can decimate insect populations.

Bacteria

Over 90 species of naturally occurring, insect-specific (entomopathogenic) bacteria have been isolated from insects, plants, and the soil, but only a few have been studied intensively. Much attention has been given to Bacillus thuringiensis (Bt), a species that has been developed as a microbial insecticide. Bacillus thurin-giensis occurs naturally in the soil and on plants. Different varieties of this bacterium produce a crystal protein that is toxic to specific groups of insects. Bt has been available in North America as a commer-cial microbial insecticide since the 1960s and is sold under various trade names. These products have an excellent safety record and can be used on crops until close to the day of harvest. Bt can be applied using conventional spray equipment but, because the bacteria must be eaten to be effective, good spray coverage is essential.

Fungi

Some insect species, including many pests, are particu-larly susceptible to infection by naturally occurring, insect-pathogenic fungi. These fungi are very specific to insects, often to particular species, and do not infect animals or plants. Fungal growth is favored by moist conditions but fungi also have resistant stages that maintain infection potential under dry conditions. Fungi can spread quickly through an insect popula-tion and cause its collapse. Because fungi penetrate the insect body, they can infect sucking insects such as aphids and whiteflies that are not susceptible to bacteria and viruses.

Fungi invade insects by penetrating their cuticle or “skin.” Once inside the insect, the fungus rapidly mul-tiplies throughout the body. Death is caused by tissue destruction and occasionally by toxins produced by the fungus. The fungus frequently emerges from the insect’s body to produce spores that, when spread by wind, rain, or contact with other insects, can spread infection. Infected insects stop feeding and become lethargic. They may die relatively rapidly, sometimes in an upright position still attached to a leaf or stem, per-haps in an elevated location or concentrated near crop borders. Infected root maggot flies may be clustered on shoot tips, tall grasses, or other prominent features.



Most insect pests of vegetables are susceptible to fun-gal pathogens. Some fungi, such as the Entomophthora and related species, are fairly specific with regard to the groups of insects affected; others, such as Beauveria, have a wider host range.

Insect-pathogenic fungi usually need moisture to enable infection, and natural epizootics are most common during wet or humid conditions. The effec-tiveness of these fungi against pest insects depends on having the correct fungal species and strain with the susceptible insect life stage, at the appropriate humidity, soil texture (to reach ground-dwelling pest species), and temperature. The fungal spores, which can be carried by wind or water, must contact the pest insect to cause infection. Naturally occurring fungal epizootics may decimate aphid, root maggot fly, caterpillar, leafhopper, and thrips populations. Some examples include:

• Entomophthora muscae infects flies. Susceptible pest species include the adults of the onion mag-got, cabbage maggot, and seedcorn maggot. The fungus multiplies within the body of the adult fly which becomes enlarged; yellowish bands of fungal spores stripe the abdomen.

• Beauveria bassiana is an insect-pathogenic fungus found naturally on some plants and in the soil. Epizootics are favored by warm, humid weather. It is known as the white muscardine fungus because infected insect larvae eventually turn white or gray. Susceptible insects include the larvae of European corn borer, Colorado potato beetle, and Mexican bean beetle. Unfortunately, natural enemies, such as some lady beetles, can be susceptible to some fungi.

Viruses

Insect-specific viruses can be highly effective natural controls of several caterpillar pests of vegetable crops. Different strains of naturally occurring nuclear poly-hedrosis virus (NPV) and granulosis virus are present at low levels in many insect populations. Epizootics can occasionally devastate populations of some pests, especially when insect numbers are high.

Insect viruses need to be eaten by an insect to cause infection, but may also spread from insect to insect during mating or egg laying. In some cases, for ex-

ample while searching for suitable hosts for egg laying, beneficial insects such as parasitoids may physically spread a virus through the pest population. Insect viruses pose no threat to humans or wildlife. Viruses can overwinter in the environment or in overwintering insects to re-establish infection in subsequent seasons. The successful commercialization of insect-pathogenic viruses has been limited.

Viruses invade an insect’s body via the gut. They replicate in many tissues and can disrupt components of an insect’s physiology, interfering with feeding, egg laying, and movement. Different viruses cause different symptoms. NPV-infected larvae may ini-tially turn white and granular or very dark. Some may climb to the top of the crop canopy, stop feed-ing, become limp, and hang from the upper leaves or stems, hence the common name “caterpillar wilt” or “tree top” disease. Victims of a granulosis virus may turn milky white and stop feeding. In both cases, the body contents of the dead larvae are liquefied and the cuticle ruptures easily to release infectious viral particles. Death from a virus infection usually occurs within three to eight days.

Naturally occurring viruses may affect many caterpillar pests of vegetables. Isolates of NPV have been suc-cessfully tested in field trials against corn earworm, imported cabbageworm, cabbage looper, armyworms, and European corn borer. Preparations of granulosis virus have been isolated from several caterpillar species, including imported cabbageworm, cabbage looper, armyworm, and fall webworm.

Nematodes

These are not the plant-attacking species of nematode, but beneficial, insect-attacking nematodes (or very small roundworms). Many species of naturally occur-ring, beneficial nematodes live both in the soil and on plant material. The role of many of these species is not well known, but some nematode species have received attention as potential biological control agents. Several species can now be mass produced and some are avail-able commercially.

The commercially available nematodes are species of Steinernema and Heterorhabditis. Mass reared nema-todes are shipped live as a suspension within a specially formulated gel, as a slurry adhering to sponge mate-rial, or in clay. When water is added, the nematodes



are released from their carrier. These nematodes are too small to see without a microscope and there may be millions of squirming little worms in each handful of soupy mixture.

Some nematodes actively seek suitable hosts, often attracted by the carbon dioxide emitted by their prey. Others wait for passing prey. They carry insect-patho-genic bacteria within their gut. Different nematode species carry different species of bacteria. Once the nematode penetrates its host, usually through any available opening, the bacteria multiply and kill the pest by septicemia. The nematodes feed on the bacteria and insect tissue, then mate, and reproduce. After one to two weeks, young nematodes emerge from the dead insect to seek out and colonize new hosts. Affected insects usually die within one or two days. Those killed by Steinernema species turn a brownish-yellow color from the bacterial infection. Insects killed by Heterorhabditis nematodes become red and gummy.

Many vegetable pests are susceptible to attack by nematodes but, for many, the potential of nematodes for field control has yet to be evaluated. Candidates for control include soil-dwelling larvae such as those of cucumber beetles, cutworms, and armyworms, carrot, sweet potato, and other root weevils, Japanese beetle, squash borers, root and seed maggots, and fall armyworm and corn earworm in corn.

Types of biological control

Conservation

The conservation of natural enemies is probably the most important and readily available biological control practice available. Natural enemies occur in all veg-etable production systems, from the backyard garden to the commercial field, they are adapted to the local environment and to the target pest, and their conser-vation is generally simple and cost-effective. With relatively little effort the activity of these naturally occurring beneficials can be observed. Lacewings, lady beetles, syrphid fly larvae, and parasitized aphid mummies are almost always present in aphid colonies. Fungus-infected adult flies are often common follow-ing periods of high humidity. These natural controls are important and need to be conserved and considered when making pest management decisions. In many

instances the importance of these naturally occurring beneficials has not been adequately studied. The best we can often do is to recognize that these factors are present and minimize negative impacts on them.

Classical biological control

In many instances the complex of natural enemies as-sociated with an insect pest may be inadequate. This is especially evident when an insect pest is accidentally introduced into a new geographic area without its associated natural enemies. These introduced pests comprise about 40% of the insect pests in the U.S. Examples include the European corn borer, cereal leaf beetle, and Japanese beetle. To obtain the needed natural enemies we turn to classical biological control. Classical biological control is the practice of import-ing and releasing natural enemies to help control introduced pests, although it is also practiced against native insect pests. The first step in the process is to determine the origin of the introduced pest and then collect appropriate natural enemies (from that location or similar locations) associated with the pest or closely related species. The natural enemy is then passed through a rigorous quarantine process to ensure that no unwanted organisms are introduced. The natural enemy is then reared, ideally in large numbers, and released. Follow-up studies are conducted to deter-mine if the natural enemy successfully establishes at the site of release and the long-term impact (benefit) of its presence.

There are many examples of successful classical biological control programs. Damage from the al-falfa weevil, a serious introduced pest of forage, was substantially reduced by the introduction of several natural enemies. There are many classical biological control programs underway across the U.S. and around the world.

Augmentation

The third type of biological control is augmentation, which involves the supplemental release of natural enemies. A relatively few natural enemies may be released at a critical time of the season (inoculative release), or literally millions may be released (inunda-tive release). Additionally, the cropping system may be modified (habitat manipulation) to favor or aug-ment the natural enemies. An example of inoculative release occurs in greenhouse production of tomatoes



and cucumbers. Periodic releases of the parasitic wasp, Encarsia formosa, are used to control greenhouse whitefly; the predacious mite, Phytoseilius persimilis, is used for control of the two-spotted spider mite.

Lady beetles, lacewings, or parasitic wasps such as Trichogramma are frequently released in large num-bers. Recommended release rates for Trichogramma in vegetable or field crops ranges from 5,000 to 200,000 per acre per week depending on level of pest infesta-tion. Research over the past several years has demon-strated the Trichogramma ostriniae, an egg parasitoid originally from China, is effective for suppression of European corn borer in sweet corn. Releases of 30,000 wasps per acre when corn is 18 inches tall and corn borer is active should result in suppression of the pest and damage. The released female wasps seek out and insert their eggs into eggs of European corn borer. Larvae hatch from the eggs and consume the contents of the corn borer egg, killing the developing borer larvae in the process. From these eggs emerge more moths and the process continues through the season. T. ostriniae does not survive winters in New York so it has to be released each year – fields need to be “in-oculated” each season. This species is now available for purchase and release. Recent work has shown that T. ostriniae also holds potential against corn borer in peppers and potatoes.

Many commercial insectaries rear and market a variety of natural enemies including predaceous mites, lady beetles, lacewings, praying mantids, and several spe-cies of parasitoids. Success with such releases requires appropriate timing (the host must be present or the natural enemy will simply die or leave the area) and release of the correct number of natural enemies per unit area (release rate). In many cases, the most effec-tive release rate has not been identified as it will vary depending on crop type and target host density. Suc-cess also requires a healthy and robust natural enemy.

Conserving and encouraging natural enemies

Natural enemies are present all systems and their conservation and enhancement should be encouraged. Manipulating the farm system to augment the effective-ness of a natural enemy is relatively straightforward.

Most beneficial wasps, flies, and many of the predatory insects benefit from sources of nectar and the protec-tion provided by refuges such as hedgerows, cover crops, and weedy borders. Mixed plantings and the provision of flowering borders can increase the diver-sity of habitats and provide shelter and alternative food sources. Examples of habitat manipulation include the planting of flowering plants (pollen and nectar sources) near crops to attract and maintain populations of natural enemies. For example, syrphid fly adults can be attracted to umbelliferous plants in bloom. Caution should be used with this tactic because some plants attractive to natural enemies may also be hosts for certain plant diseases, especially plant viruses that could be vectored by insect pests to the crop. Although the tactic appears to hold much promise there are only a few examples that have been adequately researched and developed.

Lady beetles. Some species, in particular Coleomegilla maculata, consume pollen as an important part of their adult diet. A source of nectar and pollen, or an artificial substitute, in the vicinity of the crop may attract adult beetles and may reduce dispersal of this and other lady beetle species. Lady beetle adults also benefit from high humidity and nearby shelter, for protection from adverse weather and to provide overwintering sites.

Early season populations of some lady beetles may develop on aphid-infested perennials or shrubs. Col-lection and redistribution of lady beetles is effective but time consuming. The beetles should be handled gently and placed in groups at the base of plants, rather than broadcast. Hibernating adults, congregating in protected spaces, should not be disturbed as they are vulnerable to attack by predators and parasitoids if uncovered.

Lastly, a healthy soil with ample organic matter is not only good for crops, but can profoundly influence the nematode community structure. A healthy soil can increase the total number of nematodes so that predaceous nematodes and nematode attacking fungi can flourish. Generally, a healthy soil tends to reduce plant-attacking nematodes.

Given the lack of our full understanding of natural enemies and their interactions with pests, the best we can often do is to learn what they look like or signs of their activity and then minimize disturbance of the system.



References and additional reading

Bat Conservation International. 2000. <http://www.batcon.org/>.

Cunningham, S. J. 1998. Great Garden Companions—A companion planting system for a beautiful chemical-free vegetable garden. Rodale Press: Emmaus.

Flint, M. L. and S. H. Dreistadt, 1998. Natural En-emies Handbook—the illustrated guide to biological pest control. Univ. Calif. Div. Agric. and Nat. Res. Publication 3386.

Weeden, C., A. M. Shelton, L. Yi and M. P. Hoffmann. Biological control: A guide to natural enemies in North America. World Wide Web Document. Cornell

University <http://www.nysaes.cornell.edu/ent/biocontrol/>

Credit, excerpted material

Some of the material contained in this proceedings was excerpted from the following publications.

Hoffmann, M. P. 1999. Biological control of insects: Past, present and future. pp. 9-12. In K. Stoner (ed.). Proceedings, Farmer/Scientist Conference on Alterna-tives to Insecticides in Managing Vegetable Insects Dec. 6-7, 1998, New Haven, CT. NRAES-138, Ithaca, NY.

Hoffmann, M. P. and A. C. Frodsham. 1993. Natural enemies of vegetable insect pests. Cooperative Exten-sion, Cornell University. 64 pp.



What’s different about insect management on organic farms?

Scale and diversity

While its not always the case, organic vegetable farms tend to be smaller in acreage and at least as, if not more, diversified than conventional farms. This has the benefit that there are smaller plantings of any given crop at any given time (no massive monocultures), but the disadvantage that it can be difficult to rotate as far as is needed to escape a given pest. Another benefit is that is spreads the risk. If you lose one crop in a given year, you have 70 others to sell. If you lose the early planting, there will be several more coming along.

Attitude

I find that organic farmers are willing to tolerate higher levels of damage as the crop grows, and sometimes in the final product. Sometimes this is based on a certain philosophical view of nature and farming (nature is basically benign; as a farmer I am working with nature, not trying to overcome it; there is abundance enough to provide for what I need and the bugs, too) or sometimes its just ac-cepting and making the best of what you can’t do anything about (the flea beetles are munching on my early brassicas, but I can’t afford row cover and

I’ll just hope they tough it out and outgrow it; OR leafhoppers brought down my potatoes early, so I’ll just harvest them now, put them in small bags, and charge extra for small potatoes). Another approach is, if one crop is too difficult to grow organically, I’ll grow a different crop.

Market demands

While wholesale organic markets can be just as de-manding (zero tolerance for damage) as conventional markets, many organic growers choose markets that have more tolerance for damage, and this provides some leeway. This includes farmers markets and CSA’s. Holey brassica greens (from flea beetle dam-age) go over OK in a CSA box or at a farmers market, but they would not do so well in a pallet going to Bread and Circus. NO markets get excited about wormy corn. However, I know organic farmers who are succeeding very well in very demanding wholesale markets and I know organic CSA’s and farm stands who only put out the very best quality.

More attention to rotation, soil building and cover crops

On most organic farms, there is more willingness to invest in long-term soil building and to take land out of active production for a year or more and put it into cover crops. There may be more thought given to

Insect Management: Managing Beneficial Habitats, Using Organic Insecticides

Ruth Hazzard Dept. of Entomology

University of Massachusetts Extension Amherst, MA 01003

Phone: (413) 545-3696 Email: [email protected]



rotational planning (though I find that conventional farmers do a lot this planning, too).

More commitment and interest in long-term whole-system strategies

There are organic farms that have been able to reach the point where they don’t spray any organic pesti-cides and they have high-quality crops all season long. This represents the outcome of years of watching, adjusting, fine tuning, combining a whole array of practices and choices to create a whole system that works. It also requires adjusting what you grow and when, as well as using a host of cultural practices to minimize pests.

Beneficial insects (predators and parasites) have more opportunity to build up

Beneficial insects (predators and parasites) have more opportunity to build up to higher population levels, and very likely have more impact on pest populations. These natural enemies include lady beetles, spiders, spined soldier bugs, insidious flower bugs, green lace-wings, syrphid fly larvae, and a host of parasitic wasps. Often you don’t know these are present until you knock them out. There are only a few broad-spectrum toxins that organic growers can use (rotenone, pyrethrin), and most use them very sparingly.

The most striking example I’ve seen of this is corn leaf aphids in sweet corn. Aphids colonize organic corn just as they do conventional corn, but in years of scouting both types of farms, I’ve never (really, not ever! as strange as it may seem) seen the huge buildup of aphids in tassels on organic farms that is fairly common in conventional sweet corn. The difference: conventional farms routinely use broad-spectrum insecticides at least once in most corn plantings, knocking out natural enemies. Another factor may be the type of fertilizer. High levels of nitrogen from soluble fertilizers tend to foster higher aphid populations. In peppers, we have documented that use of permethrin results in aphid outbreaks, compared to very low numbers where no broad-spectrum insecticides were used.

You can’t just knock out the pest, so you get creative

There are a number of key pests for which there is no knockdown organic insecticide. This means that you

have to find other means and you are willing to try more expensive, creative, and innovative strategies.

Costs are higher

This all adds up to the fact that it costs more to produce a bushel of a given organic produce than it does to produce a bushel of conventional produce.

Prices are higher (sometimes)

The price differential is especially noticeable at the wholesale level, especially when demand is high and supply is low in the organic channels. The value of a box of wholesale organic produce in mid-season is the envy of any conventional farmer. At the farmers market, consumers may or may not care enough to spend more at your stand than someone else’s who is not organic. CSA growers get essentially retail prices, without as much of the cost of running a retail stand.

What insect pests are the biggest challenges?

Beetles

Beetles, especially the leaf-feeding beetles (Chrysome-lids): Colorado potato beetle, flea beetles, cucumber beetles. The options for beetle control (rotenone, py-rethrin) are short-lived and not very effective. These beetles overwinter as adults in field borders, colonize the crop very fast, and cause immediate damage. Some (e.g. striped cucumber beetles) also vector diseases. Lack of control in one year or one generation can result in buildup of populations in the next generation or next year. In a small-scale farm, it is difficult to rotate far enough to escape them. However, the ar-rival of spinosad as a control option will make some of these easier.

Migratory pests

These arrive suddenly in large numbers, do not have many natural enemies, and can be difficult to control. These include corn earworm in corn, and potato leaf-hopper in beans, and potatoes.



Root maggots

Root maggots, such as cabbage root maggot fly, which attacks spring brassica crops. Efforts to find effective biocontrols have failed. Row covers, soil health, crop rotation, and plant timing are key strategies.

Thrips

Thrips attack onions and cole crops. Often not a pest, but can bring crops down at high numbers and if crops are otherwise stressed.

Tarnished plant bug

This pest has a huge host range and causes damage to fruit (e.g. strawberries) and leaves (e.g. basil, pepper)

Mexican bean beetle

What pests are easy to deal with?

Caterpillars, especially those on brassicas. Bacillus thuringiensis (Bt) products work very well. Euro-pean corn borer in sweet corn also can be effectively controlled with Bt sprays. Spinosad will add another effective tool.

What strategies help organic growers successfully prevent losses to insects?

Soil health, good production practices

Healthier crops do sustain less damage or tolerate and outgrow damage more readily.

Using IPM tools

Prevent pests using cultural practices, monitor pest conditions in the field; spray at the critical time the pest reaches economic thresholds. An example: an organic pepper grower who uses pheromone traps to detect European corn borer flight, then when the threshold is reached, applies Bt every 4-5 days during the flight period. Another example is a sweet corn grower who

uses the pheromone traps to detect corn earworm flight, and applies oil to fresh silks when the flight reaches damaging levels.

Timing of plantings

Timing of plantings can help avoid periods of high pest pressure.

Plantearly

Sweet corn: plant by mid May to avoid corn earworm, which migrates into the region in late July or August.

Plantlate

Potato: plant early or mid June to avoid Colorado potato beetle, which emerges from overwintering sites late May to mid June. If beetles find no food source, they migrate elsewhere in search of host crops. Use early varieties to ensure maturity before season’s end.

Crucifers: plant after mid-May to avoid spring cabbage root maggot fly (first flight active from late April to mid May); plant after mid July to avoid the first generation of flea beetle.

Vine crops: set out transplants after the middle of June to avoid the worst of the striped cucumber beetle, and get past the most susceptible early stages (cotyledon to 3 leaves).

Floating row covers. There are several different weights of floating row covers (e.g., Reemay, Typar), spun-bonded polypropylene covers, which can be laid directly over the crop or supported by hoops. Air and water travel through the cloth, but insects cannot (assuming edges are sealed). This is an excellent pest control as well as providing some frost protection and added air and soil warmth for earlier yields. Widely used by organic growers for:

1. Cabbage root maggot fly on spring crucifers. Eggs are laid at the base of the stem by first-generation adults, which fly from late April to mid May. Maggots feed on roots and kill early cole crop seedlings. Row covers are a very effective control.

2. Flea beetles on greens (crucifers and others). Tiny black beetles cause shot-hole feeding. Can be used all summer on direct-seeded crops, or in spring



or fall on transplants. Too hot for transplants in midsummer.

3. Leaf miner on spring spinach and chard. A fly which lays eggs on underside of leaves, maggots tunnel inside leaf.

4. Cucumber beetle on melons, summer squash, cukes, winter squash. Protects both from feeding damage and vectoring of bacterial wilt. Must be removed at flowering.

5. European corn borer on early corn. Speeds growth of early corn and protects from moths if left on into mid to late June, after first flight has peaked. Apply loosely to allow for corn growth.

Interplanting and bio-strip intercropping

Build into the farm plan plants which provide resources for natural enemies, including those in the Umbelli-ferrae and Compositae families, which attract parasitic wasps and predaceous flies and beetles because their flowers have short nectaries. These resources can also be provided in sod strips between beds, or in border areas. May be mowed at key times to encourage flow-ering, or produce mulch.

Mulch or cover crops

Using strips of unmowed rye between rows of potato or cucurbits can reduce colonization by beetles. Similarly, rye or straw mulch has been shown to reduce coloniza-tion of potato by Colorado potato beetles.

Organic pesticides: using the tools we have

Many organic growers do spray for insect pests, but the tool box is very limited. Active ingredients and specific formulated products have to be approved by the National Organic Program. Several new options have recently been developed and approved, or are expected in the next year or two.

Bacillusthuringiensis(Bt)

Derived from a naturally-occurring bacterial patho-gen, Bt has been isolated and formulated for use as a foliar spray. A tried-and-true organic tool. Organic growers use Bt kurstaki (Dipel DF, Javelin WG or Bt aizawi (e.g. Xentari) products against caterpillars and

Bt tenebrionis (e.g. Novodor, Beetle Beater) against Colorado potato beetle. These are only good against larval stages. Some products contain prohibited inerts (e.g. mineral oil in Dipel ES) or have been genetically manipulated (e.g. Raven, Mattch) so are not allowed. And transgenic Bt plants are prohibited (as are contami-nated kernels that might have resulted from the pollen of your neighbor’s Bt corn). The manufacturer of Dipel has produced a special formulation of Dipel ES for the organic market, and it is making its way through the approval process. This is an indication that the organic farming industry has grown to a significant size.

Insecticidalsoaps

Insecticidal soaps are made from the soaps of fatty acids, and are used as contact insecticides to control soft-bodied pests such as aphids, thrips, whiteflies, leafhoppers, some immature caterpillars, and mites. Good coverage and repeated applications are impor-tant, but it does work. Non-persistent, low toxicity. (M-Pede, Safer’s Soap, Concern).

Vegetableoil

Used against corn earworm in direct silk applications to sweet corn. Corn oil or soybean oil may be used. Acts by creating a suffocating barrier to larvae crawl-ing down the silk channel. Most effective when mixed with a Bt product. Exempt from FIFRA and food toler-ance requirements. A specially-designed oil applicator (Zealater) is available from Johnny’s. For more info, see <http://www.umassvegetable.org/>.

Beauvariabassiana

One of several naturally-occurring fungal pathogens of insects. Spores are applied directly to insects or to plant surfaces or other habitats (e.g. soil), where insects pick them up on their bodies. Under favorable condi-tions (warmth and high humidity), spores germinate and penetrate the cuticle, and produce toxins that kill the insect. Hyphae grow fill the insect’s body, often producing fuzzy white growth that is visible on the outside. Most effective when used in high humidity environments. (Naturalis-O, Botanigard 22W, ES, Mycotrol) GH, field. Note that Botanigard ES can cause oedema in greenhouse tomatoes; use the 22W formulation on tomato.



Kaolinclay

Fine white clay which disturbs insects’ visual and tactile cues on host plants; adheres to insects. Beetles, soft-bodied insects. Labeled for flea beetles on fruit-ing crops, and cucumber beetle on cucurbits, thrips on onions. (Surround WP). Wear a mask or respirator to protect from inhalation.

Spinosad

Derived from an actinomycete fungus that is patho-genic to insects. Spintor 2SC has been on the market for several years, but was not allowed for organic produc-tion. In 2003 there will be a newly labeled formulation (Entrust) that has NOP approval. It is effective against caterpillars, Colorado potato beetle (CPB), thrips and leafminers and is labeled for fruiting vegetables, potatoes, brassicas, and cucurbits. This will be a big boon for CPB control, because it works against adults.

Botanicals (extracted from plants)

Neem

Extracts from the tropical neem tree have been used for centuries in insect control. Neem oil acts upon immature insects an insect growth regulator, disrupt-ing their molting process. It is also an antifeedant and oviposition deterrent. It works slowly and should be applied several times well before numbers reach dam-aging levels to get the best results. (Azadirect, Azatin, Neemix, Bioneem, Align; Trilogy 90, Neemazad, Triact; active ingredient is azadirachtin).

Rotenone

Broad activity against a wide range of insects, espe-cially beetles. Hard on beneficials; highly toxic to fish; applicators should use protective gear.

Pyrethrin

From the flowers of certain species of Chrysanthemum. Broad activity as a nervous system toxin, against a wide range of insects. Hard on beneficials, but low mam-malian toxicity. Often mixed with piperonyl butoxide (PBO) as a synergist, but this makes it prohibited. Pyganic Crop Protectant is currently the only approved pyrethrin product.

Hotpepperwax

Capsacin (the “hot” component in hot peppers) micro-encapsulated in a mixture of mineral oil and paraffin, which adheres to plant surfaces. Acts primarily as an insect repellent, but is also a toxin to insects and mites. Looked promising vs. flea beetle in brassica greens in a UMass trial in 2002. (Hot Pepper Wax Insect Repellent)

Garlicoil

(Envirepel, Garlic Barrier, Garlic Grow)

More on biological control

Conservation of natural enemies

As mentioned above, using selective insecticides that do not harm beneficials, and providing them with re-sources such as nectar and shelter, increase the level of biocontrol that is taking place. In certain instances, augmentation, or the release of mass-reared benefi-cials, can also help in suppressing pests. This tends to be more successful in greenhouses than in the field, but there are now several instances where releases in the field have been proven to suppress, if not completely control, key pests.

A useful directory for choosing a natural enemy sup-plier is Suppliers of Beneficial Organisms in North America available from the California Environmental Protection Agency, Dept. of Pesticide Regulation, En-vironmental Monitoring and Pest Management, 1020 N St., Rm. 161, Sacramento, Calif. 95814-5604. tel. 916-324-4100 (http://www.cdpr.ca.gov/docs/ipminov/bensuppl.htm).

Two helpful sources for biological controls located here in the Northeast are:

The Green Spot, Ltd. 93 Priest Rd. Nottingham, NH 03290-6204 (603) 942-8925

IPM Laboratories, Inc. Locke, NY 13092-0300 (315) 497-2063



Examplesofmass-rearedbiocontrolorganismsforvegetablecrops

1. Beneficial nematodes. Nematodes are very small roundworms. Some species are plant pathogens, but some attack soil-dwelling insects and two in particular (Steinernema and Heterorhabditis) have been mass-reared for commercial use. These seek out and penetrate their host insects, multiply within the host and kill it. Most likely to be effec-tive against the soil-dwelling immature stages of susceptible hosts, such as root weevils, cutworms, white grubs (use Heterorhabditis), wireworms, and maggots. Require moist soil conditions to survive.

2. Pediobius faveolatus is a small parasitic wasp of the Eulophid family, which attacks larvae of the Mexican bean beetle. To purchase Pediobius, contact: ARBICO, (800) 827-2847 (AZ), (http://www.arbico.com/); The Beneficial Insect Com-pany (NC), 336-973-8490 (http://bugfarm. com/) ; Rincon Vitova (CA), 800-248-2847 (http://www.rinconvitova.com/) or The Green Spot (NH), 603-

943-8925 For more information, you can contact: Carol A. Holko, Maryland Department of Agri-culture, Plant Protection and Weed Management Section, 410-841-5920 (http://www.mda. state.md.us/plant/mex.htm)

3. Other species in this family include Edovum put-lerii, also an egg parsitoid, which can be released to control Colorado potato beetle in eggplant (not effective in potato).

4. Trichogramma spp. These tiny wasps lay their eggs inside the eggs of insects, and wasp larvae develop inside, killing the egg. Several species are commercially available, but the most useful in gardens would be T. pretiosum for caterpillar eggs. Releases should be timed to coincide with egg-laying. Another species, T. ostriniae, is now available and is very effective against European corn borer. Ask supplier for instructions on release. Sources for T. ostriniae: Beneficial Insectaries, 800-477-3715, IPM Labs (see above).



This kind of meeting is great. When I first started out there was no research, people, anything about how to grow a crop organically. There was nothing. There was no information, no interest, and in the last 10 to 15 years it is amazing how much good research is going on for our benefit. A lot of it’s for ground water protection and other issues but it is benefiting us organic people tremendously. Most of us farmers won’t change unless the research is there to show us that things actually work. Any of you that have been farming for a while know that it’s always an ongoing research project. The years are never the same. You’ve got different growing conditions, different crops, different bug pressures. Things that work one year don’t work at all the next. So it’s not an exact science, which is what is part of the fun of farming.

We started out 20 some odd years ago, self-serve with a bench. Then the next year another bench and the next year another bench then put some people, started hiring full time and a steady progression over fifteen years adding up to where we are presently do-ing around 20 to 25 acres of field crops and around a half acre of greenhouse. We’ve been trying everything over the years. We don’t have a single system on the farm that works, we have a bunch of systems and we keep trying new things and we keep going to meet-ings and learning more. We’ve done a bunch, we try a bunch and for the most part it is working out pretty well. We are a direct retail. We have a farm stand.

90-95% of our crop that we grow goes to our farm stand so that makes the market different than a lot of other people. We can talk to our customers. They can ask us questions.

Insect and disease control is what I am supposed to be talking about. I think in organic farming that is almost one of the easier subjects. To some extent there are not that many things we can do. I would guess that I spend less on 25 acres of property, where we are grossing $100,000 or something like that in vegetables, we spend less than $200 a year on average on chemicals. Most of insect and disease control revolves around your cultural practices. Whether it’s planting a little bit later, going to transplants instead of seed. All of those things that they talked about earlier today. The cultural practices are probably the number one resource that we have to take care of the insects and disease.

Tremendous amount of beneficials out there. Once you start looking you realize that, yeah, there are aphids on those plants but don’t spray them because you’ve got four different kinds of beneficials out there taking care of it. Give it some time. In 20 years I think I had to spray a pepper crop once. Because the aphid population was just too high and I didn’t think it could balance out. It was probably there from in the greenhouse. I’ve gotten better. They don’t go out in the field with aphids already on them. I don’t know if that is what it was but in 20 years I’ve only had to spray pepper plants

Pest Management on Applefield FarmTranscript of a presentation by:

Steve Mong Applefield Farm

Stow, Massachusetts



once for aphids. Tomato plants the same way. I think one year the balance was out of whack. The hornworm was just too big. We sprayed them once. Many times I have thought about spraying. I didn’t want to affect the natural population. I lost a few leaves but then sure enough the natural beneficial comes in and takes care of the problem.

A couple of other notes. I do a lot of beneficial stuff. Our greenhouse, we have almost up to a half acre of greenhouse now, its getting to be one of the bigger parts of the operation. I rely tremendously on brought in beneficials. In that enclosed environment they work extremely well for almost all of the insect pests that you might have. I’ve been doing the Trichogramma for years, ostriniae now and the pretiosum before that. I think that there is a lot of new research coming out and the rearing processes for some of these beneficials is getting better so the price is coming down. It is becom-ing more of a viable option on some of these crops.

I’m going to rely a lot on individual questions. The disease and insect control is so dependent on what is going on in your own farms. I’m happy to tell you what I do. A couple of the major crops I’ll talk on briefly is something like tomatoes. For us and for anybody prob-ably it’s one of the number one value crops we grow. Insects to me are not a problem on tomatoes; I have never had, like I said once I had hornworm. Disease is an issue and what we’ve worked out is we plant three distinct crops of tomatoes. An early planting, the main season planting and I’ll put in a late planting of tomatoes so that they are just starting to bear for the first of September which I consider the hardest time to keep tomatoes coming in. So they are young, they haven’t even produced yet, they are coming in at the end of the season.

We will work hard not to pick one crop of tomatoes and another crop in the same day. I don’t want to spread disease from one to another. Keep them separated, stay out of them. Disease management. When the plants are wet don’t go in there. And you can really significantly extend your tomato-growing season without anything. I have to say I have in the last couple of years used a new product called Oxidate. Sometimes known as Zerotol. With this mist blower have been able to go through and have a surprisingly good late season crop of tomatoes. The cleanest I’ve ever seen.

Corn, Ruth mentioned. I’ve worked with Ruth Hazzard for almost 10 years on that corn earworm project. Built my own applicators for a while. People used oil cans and little bits. It doesn’t have to be high tech. I started out the first year I actually tried it I had my acres of corn and I just did, I think, four rows. Two down and two back, and I tried to time it so that I could pick that on the weekend.

Because we have regular customers where we are pick-ing and they learned about the worm and they didn’t like it when it showed up. But we left a knife on the table they could leave the worm with us. It was okay but your sales do go down. But weekends it was a whole other crowd there is enough tourist activity and new people driving by and boy the customer comes in and your whole farm stand is judged by that one ear of corn. It’s so disturbing to have them just “Ugh” and just run out of the door and you will never see them again. I saved this corn and I only picked it for the weekends. It only lasted that one weekend but I saw a remarkable difference in the numbers of ears. It wasn’t 100% but it probably went from 40% clean to 60% or 75% clean. I’m not a researcher but if you don’t hear too many squeals it is better. And so Ruth started this program, so we have been doing this for quite a while.

This past year we had such a drought where I am that I had a choice to water the corn or do the oiling and I watered the corn and the customers dealt with it. But the year prior to that I oiled almost all of the late season corn. It doesn’t come in in the early season, it’s the last month or so. It’s not that daunting of a project and the corn was pretty darn good. I’m disappointed because I did put the ostriniae out there because I was thinking okay now I’ve got the corn borer protection and I just never followed up with the earworm protection. So those are the two main crops, corn, and I don’t have aphids on the corn there are just tremendous beneficials out there. You have to be careful picking your corn to not squeeze the immature ladybug larvae that are running all over it.

Two other of the major pests that Ruth just mentioned. Leafhoppers, what a pain. And striped cucumber beetle primarily. But cucumber beetles there are so many even in the rotation all the pumpkins and squash and cucumbers and zucchini and gourds get mixed up around. But they are everywhere. Our answer for the striped cucumber beetle for the most part is we have gone back to all transplants so the plants are bigger



when they go in. Take off quicker. A lot of things we will plant a little bit later so the ground is warmer. They will grow quicker and it gets them out of that most susceptible stage. We did do the Surround two years ago in the transplant trays. That does make a difference. I don’t like working with the Surround. I’m not sure if I will keep working with it. We were never a certified organic operation, being a direct retail we could talk. I followed MOFGA’s rules, which is Maine organic farmers. Currently we are probably not going to go through the certification. I’m not sure how close we are going to follow. If we had to go around with a pump sprayer to spray a little bit with a rotenone pyrethrin is what we used to use. But again cultural practice and I think with some of this new trap cropping there are some improvements on that end.

Leafhopper that is one that to some extent we like the leafhopper coming in. That’s our natural burn down. The plants decline so it hardens the potatoes off, so long as it doesn’t come too early. There were a few times that I had to spray and that is one of the few times I used this machine here (backpack mist blower) and rotenone pyrethrin was allowed, this was probably three years ago. Last year we didn’t really have much of a leafhopper problem. I don’t know why. We were lucky. They do vary tremendously year to year. That is the problem with some of these pests. They all fire up one year and the next year they are not there. It’s a tough one.

When I was spraying the pumpkin field. One of the advantages and I guess I’ll briefly talk about the mist blower. This is a motorized backpack sprayer. I bought it primarily to use in the greenhouse. They run about $500. Some of these other sprayers people buy are $2,000-$3,000 and I don’t have that big of an operation. I’m real surprised; we use that in the field a little bit. Primarily we rely on the pump sprayers and for the most part they do pretty good. The really nice thing about having a wind coming out is if you want to get material under, sometimes I have used it on the pumpkins and watermelons, real low rpm, walk around and you can just see that the plant is just blowing over. You are getting material all over it and I was real leery.

The project we had last year with the corn project where Ruth wanted everyone participating to spray two applications with BT for corn borer. I’m going “I don’t have a sprayer. I can get over little corn but I can’t drive the tractor over big corn. How am I going

to spray acres of corn?” I sorted it out. I could spray with one tankful; I sprayed close to a half acre plus. Which is the concept of a sprayer like this. They call it low volume. Which means low volume water. You’ve got the same amount of material going on per acre. Instead of using 50 gallons of water or 25 gallons of water you are using two or three gallons of water. Very low water with a very high concentration in the tank but the application, as the droplets come out it drops into the air stream and it gets sheared off so it breaks whatever chemical you happen to be using into very small particles. To give a complete coating of whatever you are spraying.

It is really difficult to get used to the concept of us-ing a tool like this because the concentrations are so high. I might put a quarter pound of BT in that two and a half gallons of water. It’s a hard concept but for certain crops it makes a lot more sense than spending a few thousand dollars on a sprayer that you would use once or twice a year or every three or four years. It is just something to keep in mind. This is the least expensive thing I know for a mechanized sprayer that can do some acreage. People who have a small orchard application these things are great. If you are just doing ten or 15 trees. Peaches, apples, whatever. It’s an interesting tool.

I can talk more about any of this stuff, so questions would be great at this point because I don’t have much material.


Q: How far does the mist go from the nozzle?

A: If there was a hanging basket hanging up in the corner I could spin it. Roughly a 200-mile per hour wind coming out. That’s probably pushing it. If you were trying to do full sized apple trees you would have to walk into the tree and really work on it. It’s got some distance and that’s why I like it in the greenhouse. It’s why I bought it in particular, because I can walk down the greenhouse and get what I need and then actually see the hanging baskets doing this. I’ve got coverage.

Q: Is there a concern with spray drift? Sometimes you only want to spray one crop.



A: True. Again you can adjust the airflow; you can adjust the droplet, so that when I spray I’ve got like two rows of tomatoes side by side on plastic. I’m con-centrating my spray on the tomato plant. You’ve got very good control. If I was trying to grow an organic crop next to a non-organic crop I couldn’t guarantee that there isn’t going to be a little bit of a drift but there isn’t much. So if you are worried about that you can walk down the other side of the plant. But pretty much if you need it to go the distance you can wait for it to get out there or you can adjust the droplet size, slow it down. They also have a diffuser; and different nozzles that you can put on to broaden or do different things with the exhaust. It’s certainly no more of a problem, you have the same problem with the pump up sprayers if you’ve got two or three rows and if the wind is blow-ing there is some drift. Whenever you spray anything there is always a concern with drift. No more than, I don’t think, any more than most things.

Q: How do you calibrate a mist sprayer?

A: That’s what I say it’s really a tough thing. The very best thing to do is fill it up with water, walk down whatever area you are going to be doing. Some of it is going to depend on, do you like to stroll, do you want to just take your time or are you willing to walk as fast as you can walk. It all depends on your pace to how long the water lasts. So if you know an area and go and spray that so you know OK that’s a quarter acre. Now you know if you can only do half of that well then. You are only doing a quarter of it so it’s all individual, it’s going to depend.

Some people it takes some knowledge, because you can adjust the droplets going in there. So you can make flow fast so you see a bunch of material or you can make it flow so you almost don’t see that there is anything coming out. So it’s all in your comfort, but many people make the mistake of using this and to do a half acre they would fill up the tank eight times. It is just too much work. Once you get a little comfortable with it concentrate that spray material, but you have to gain the experience.

In the greenhouse I have gotten to the point where I know, because out in the fields they talk about so many pounds per acre. You know all of us small farmers we are doing a couple hundred of row feet, how much of an acre is that. In the greenhouse everything is done by amount of material per hundred gallons. Well I’ve

finally figured out that in my greenhouse operation I treat that 2 1/5 gallons as if it was 25 gallons. That seems to work pretty good for me. I am treating the equivalent area that 100 gallons dilute would take care of. You have to gain some experience and it is not that easy and it is not that hard either.

Q: You’re using Oxidate against tomato diseases?

A: Yeah OxiDate, ZeroTol. Are people familiar with it at all? Zero tolerance is what it first came out as and that was registered for greenhouse for cleanup so it wasn’t registered specifically for vegetables. So they had to come out with the exact same formulation, but it’s got the vegetable label and it is called OxiDate. It is a hydrogen peroxide type. There is some good proprietary stuff I don’t know.

I use it a lot in the greenhouse. We do a lot of sub ir-rigation and to keep the water clean and to keep algae from forming, as a disinfectant it has been wonderful. But because of it being a disinfectant it does kill spores on contact. It has got no residual effect. You spray it, 10 minutes later it’s gone. But as a disinfectant for some of the bacterial diseases, fungus and stuff I think it has a point.

But again, as a person I don’t know if I have mentioned this but as a grower I have always hated to spray. If I can avoid spraying, I will do anything to avoid spray-ing. I read the label, just about six or seven years ago, I bought this stuff because we had smut, it was determined to be smut on our cosmos that we use as a real good cut-your-own flower. When you are cutting and you go cutting down the row and it looks a lot like powdery mildew but I identified it as smut. Anyway it was starting to take over a row and my wife said do something with it. I looked at this label and I said, “God, it says spray three days in a row and then spray once a week for the next two or three weeks.” So that’s a lot of spraying.

Part of the theory is there is now a sodium, a potassium bicarbonate. There are a number of products out there and ZeroTol is kind of in this same category. Part of the reason they said to spray three times is 90% coverage is not good enough for a lot of these diseases and even some of the insects. If you are doing apple trees and have mite problems. If you don’t get 100% coating on the tree for mites or 100% coverage for some of these soft biologicals, the diseases multiply so fast you



almost might as well not bother. So you need 100% coverage. The way to get 100% coverage, since the stuff is basically harmless, they have you spray three times in a row. So that you hit it one day and now you have got 80% of the plant, and you hit it again and you get some more, you hit it again and you might get the rest. With the mist blower, I went through, and it’s got the advantage that it does a better job. You hit the front side of the plant and it tends to draw back around. But I went back around the rows and hit from one direction, the next day I went and made sure that my application was going the opposite way. Dr. Wick, he didn’t think that we would get rid of it.

That cleaned that crop up and let us get a harvest and near the end of the season I saw it starting to come back again, but by then it didn’t matter so much. I don’t think it is a Godsend. I don’t think there has been much research done on it. But two years ago I tried it, I used one cup of OxiDate per tankful and with one tankful I could do about four 500-foot rows. So I just walked down pretty quick. Easy to fill up, easy to go spray it. Five or six days later do it again. I didn’t do any trials. It’s like all right it’s late in the season, the dew is on the plants until 11:00 in the morning, the dew is back on at 4:00 in the afternoon. It is a tough time for tomatoes and we never got around to staking these particular tomatoes up. They are Mountain Fresh, which is a nice tomato, just coming into production. There is always foliage cramped down in. I’ve got to get something in there and I do not like using copper sulfate. I avoid it like the plague if I can. I use it very very little. It worked for me and I don’t know if it is the answer but I had it, I liked the results. A lot of farming is like that. You guys must do the same thing, try things. Is that enough of an answer for OxiDate.

Q: How much does it cost?

A: Very expensive, I believe it is a hundred and some-thing dollars for a 2 1/2 gallon jug. You don’t need a whole lot on the rates. I use so much of it on the greenhouse operation I buy it by the 15 gallon drum which brings it down a little bit. It’s just now being released, they just got a new product for sanitation, for a wash dip. If you wanted to dip your tomatoes, or dip things for helping to preserve instead of using chlorine or whatever, this is now registered and it is certified it will be an OMRI approved product. I think it is basically the same material.

Q: Does the mist blower work with Surround?

A: I used it. I also painted the car beside me and it took a while for that whitewash to come off. I have no idea what label rate I used. I called up the manufacturer, I go look, because the concept is not to be used a low volume. I more or less said “well I have got to make it thick, but I can’t be too thick to go through the nozzle. I forget what rate I used, but I’m fairly impressed by how well it performed and the reason I did it with the mist blower is you just cannot get disturbance. You are only going to be painting the tops and sides of the leaves. What I would consider if you are doing it in flats, I don’t know if anybody has tried this as a dip, whether or not you could make a solution and dip the flat in so that you have got the stuff soaked. That might even be a better way and not as messy either. We had two hay wagons full of flats and I just stood up and stood back and just painted the trailer and then we took them out to the field a couple of days later and planted them.

Q: What crop and pest were you using Surround on?

A: For striped cucumber beetle before we put them out in the field. That was something that Ruth had thought might work and I said “Hey I’m a farmer, we try anything.”

Q: What do you do for powdery mildew control?

A: Nothing. Variety selection, rotation, but no I can’t. The big crops that could be a problem with powdery mildew there is no way I am going to think about go-ing and spray. I mean I possibly could, but I have not found it to be a serious enough issue to worry about it. Benign neglect works pretty good for most things. I just don’t worry about it to a large extent. If I saw it on a high value crop I would use the OxiDate. I think it would work. I don’t see those kinds of disease pres-sures enough. When I am thinking of powdery mildew, I am thinking of it primarily on the pumpkin leaves at the end of the season start getting white, and zucchinis and stuff like that. We don’t lose enough fruit to worry about it too much from my experience.

Q: What are your favorite three tomato varieties?

A: Three? Oh, well it’s not any individual. So I may grow four or five different types that I plant for an



early planting that I will pick for the farm as an early tomato. Early Cascade I use, and some of the cherry tomatoes. I have never liked Early Girl. But there is a new one this year I have done. Names I can’t remem-ber, but there is a new version of Early Girl out there that I think. No never done those. Everybody has their different areas.

Well Mountain Fresh I consider to be a late tomato, and when I first saw Mountain Fresh, this is getting off of the subject, but that is probably okay. Mountain Fresh scared me when I first saw the tomato because the plants were gorgeous, huge and healthy, the tomatoes looked good and I was worried that when I bit into it, it would be like some of these tomatoes – looks great but the skin is still in your mouth after you chew it up. It is a firm flesh, but I thought it was quite acceptable flavor and the customers don’t seem to mind it so I am real impressed.

We grow almost all determinant varieties. I used to do trellising and I wish I had the time because some years the trellised tomatoes, some years the ones on the ground or on short stakes work better. It depends on the year and amount of rain or dryness. Ideally you do a little bit of all of these different things. We are primarily doing short stake. We have done the Best Boy, Bush Big Boy, it is a Burpee one that has been pretty good. So it is not the old fashioned Big Boy it is a dwarf version with more disease resistance. I gave up Mountain Pride for Mountain Fresh. A lot less disease issues, much healthier plant. Very similar tomato we just have had better luck with it.

The big secret or what I am trying to convey is not so much variety as being sure that whatever you choose to plant for early tomatoes you know that those early tomatoes do not last. Some of them do not taste good or the plants get tired, they get early blight. We do this with many crops, beans, zucchini. You succession plant. The thing is you do not want to succession plant side by side by side because that disease is just follow-ing you right along or the insects. The big thing is to isolate some of these earlier plantings from your main season plantings from your later plantings so that you have a chance. Whether it is insects you are trying to avoid or disease. To a large extent I think it is disease for tomatoes in particular. With good cultural practices you can avoid many, many of these problems.

Q: What kind of tomato diseases are you running into?

A: The primary disease that I am worried about is I think late blight. I have not identified it. Late in the season, I think everybody, especially if you are picking off plants that have been being harvested for a while. You are coming into cultural conditions where you just don’t have much daylight. Late August and getting in to September the plants aren’t even dry until 10:00 or 11:00 in the morning. The period of leaf wetness is just incredible. The temperature is up and the amount of disease that is blowing around in the field from your fields, your neighbor’s fields or your earlier plantings is a problem.

Q: Are you thinking late blight or early blight?

A: Early blight is the more common tomato disease and then late blight is a really devastating tomato disease that comes in kind of sporadically. Some years we have it and some years we don’t but that really common one that we get every year is early blight. Don’t worry about that earliness or lateness part of the name.

It is a blight and it comes in late. I am sure Abby is right. I don’t need to identify all these things exactly. I know it is a problem and I am trying to learn ways to deal with those individual problems.

Beneficials – we talked about these. Do many people buy or are many people working on beneficials? Using beneficials? Buying in Trichogrammas?

Q: When you bring beneficials into the greenhouse how long before you see results?

A: Part of the trick in the greenhouses and for pre-ventative measure is you want to not wait. Thrips is probably the number one problem in the greenhouse. Last year was the first year that I went to 100% using a beneficial mite. I was real nervous because I hunted all season long and never saw any. I spent probably $1000 on these beneficial insects and never saw them. The only thing I know for sure is that it just could not be the first year in 15 years that the thrips just magically did not show up. I am pretty sure. That is the problem with the beneficials. Research people can get out there and put them in a cage and count how many holes are in the leaf and some of this stuff. We can’t do that. I



looked at the research. It looked promising. I did it on a small scale a year before. I felt fairly comfortable and I continued scouting.

I have to say with the thrips I had to stop using my blue sticky cards in the greenhouse because I also released a little while later an aphid predator which is a wasp so they are highly mobile. I looked at my traps for the thrips and they were just loaded with my expensive beneficial wasps so I said I would just monitor by eye. I am extremely impressed in a greenhouse operation. I have cut my chemical use down to where I spray almost no pesticide. It is not an organic greenhouse operation, but I spent probably $4,000 on beneficials and only sprayed a very small amount of pesticide.

Q: Are you doing any greenhouse sanitation to manage pests?

A: Most of my greenhouse operation we set up a sub-irrigation, it is a plug floor so that the plants are growing on the ground on a concrete, basically a pad. And the water comes up from below and waters them so again it is a cultural thing. The leaves are never wet, the plants are never wet and that eliminates, I don’t have to worry about shore flies and fungus gnats. The soil surface stays dry it is being pulled up from the bottom.

ZeroTol is in the tank mix so that it pretty much means that I do not have to worry about pathogens in the irrigation water and I may be even getting some beneficial effects because it does kill spores. Common sense in the green house, sanitation, keep it clean, air manipulation, keep the humidity at proper levels. That’s part of common sense greenhouse manage-ment. Yes, we do all of those things, which does cut down the need for fungicides, the need for a lot of these things. But in our large commercial, we’ve got a half-acre of greenhouse so it is in a quarter of an acre range of greenhouse the scale is a little bit larger than you might have.

If I was growing just for the farm and just my own tomatoes and peppers and stuff I could manage it en-tirely organic, because diseases are not an issue with those. It is the flowering plants that you have got the petals falling and then Botrytis sets in and you can just lose a lot of value in a lot of crop. My vegetables and stuff are never sprayed with fungicides. If they

are sprayed with a pesticide it is a biological, but for the last couple of years having the beneficial wasps take care of the aphids I have not had to spray them, I used to have terrible problems with the peppers and eggplant, aphids all over them. Even when you could use rotenone pyrethrin it is just like two days later they are covered in aphids again. Releasing these wasps, there is some aphid. It is not 100% clean but I don’t need 100% clean. When this stuff goes out to the field, if you don’t have a big population it gets cleaned up on its own. As long as it’s kept in control that is good enough.

Q: Do you have European corn borer problems with your peppers?

A: No, I don’t know if you heard Abby, she was wondering about European corn borer in my peppers. For about the last 10 or 15 years I have been releasing Trichogramma pretiosium as a what if. Everybody said they might work on European corn borer in the corn and it turned out with research they really do not do a damn thing. Historically, I always released them in the peppers too and I would have some mag-got problems some years but whenever I released the Trichogramma pretiosium I didn’t seem to have much borer in the peppers.

One year I listened to someone who said they really are not doing anything but I did not release any ben-eficials. We virtually did not have a pepper crop that year. Again I am a farmer, I don’t know for sure what was going on but I went back to releasing and then last year I released Trichogramma ostriniae because they are a much more efficient predator for corn borer and I released by nature. I did a release in the peppers and my corn and I had very nice peppers. I’m going to let the researchers, which they are going to set up the trials and go look and count and that sort of thing. But I firmly believe, and they are not very expensive any more. They are about $15.00 an acre. You go set a couple things up, you do that a couple of times in the season, you are all done.

Q: Any problem with eggplant flea beetles?

A: Yes, once in a while and it is usually just the young plants when you first set them out. Oftentimes it is only, we will do most of our eggplants and peppers on black plastic. Then we have a pick your own field near the stand and it doesn’t get taken care of as well so we



want to be able to easily till it under when it is done. So we will put some stuff in bare dirt. These plantings are different so it may be because of the separation, but on our farm it doesn’t matter where you plant things that flea beetles like, they are there. But in that field, that year the ones that were in bare dirt, I had to spray them. They went into the ground and they got covered, I mean you just look at the plant and the whole poor little plant is black with flea beetles. They weren’t go-ing to make it. There was no problem with the ones on the plastic. I don’t know why for sure.

For the most part what we have learned to do, and again we are not wholesalers, we have the bedding plant business, I don’t feel that we need to be the first on the market with a crop. So we have started not struggling so much to get things in the ground early, and I think that makes a huge difference on whether the pest is there or whether the plant is a little bit bigger and it grows so much faster when it gets to the ground that it grows out of the susceptible stage that much quicker. It takes away a lot of the problems. It can make a huge difference to some other operation so that is why what works for me is not necessarily best.

I would consider some other things. Sometimes there are things we want to have early. We put them out there and they are under row cover. The bulk of the crop will go in a couple of weeks later somewhere else. We are doing that more and more, especially with the pumpkins and things. We used to do direct seed and some years that was great but if you get a wet cold spring and we lost an entire 5-6 acre crop of pumpkins and squash and whatever one year. The plants just sat there at the cotyledon stage for weeks. We must have sprayed seven times with rotenone pyrethrin walking those acres but it didn’t matter. The plants weren’t growing. The striped cucumber beetle was just there and feeding and the field was done. We have gone back, as much as we do not like dealing with plastic and stuff, we have backed off. We do transplants, let them get decent size and instead of putting them in late May, first week of June we are putting them in the second to third week in June. It has solved some of those problems for us.

Q: Where do you buy your beneficials?

A: I buy a lot from Koppert. I am sure there is a web site for them. There are a number of places. Working with U-Mass extension – they bought some of these

beneficial mites from a number of different places and most of them are reared overseas and then shipped back here. Shipping is a big thing so find a company that produces and can ship them properly.

We buy a jar and they are supposed to have 100,000 mites in them. The researchers actually took a sample and counted them out and these things are microscopic. Koppert constantly had the highest count and the price is all competitive. I have had very good luck with them.

I did buy my Trichogramma ostriniae from IPM labs here in New York. Things like the Trichogramma I have a number of sources but Koppert’s has been most reliable. They are a Dutch company I believe. They have a couple of outlets here in the U.S. and they are often at some of the trade shows and things. They are quite big. They are an excellent resource.

Mike Hoffmann mentioned this earlier, or maybe he didn’t, that when you are using beneficials especially in the greenhouse, but also in the field you are really limited what you dare spray and not affect your benefi-cials. In the greenhouse your crop cycle may be only eight weeks. Something like Sevin which I know none of you guys use, I just happen to know this statistic. Sevin is still able to kill the beneficial eight weeks later or ten weeks later so it is not like you have time to spray material and then you can put your beneficial on. These materials, some persist for a long time.

Koppert’s has, it is like Spinosad is supposedly listed as soft on some of the beneficials yet it is really scary because it has a really broad spectrum. How can it be soft on the good guys? Koppert anyway has a web page where they have done a lot of research to show depending on which beneficial you are using what materials might be okay so you can help with some of your choices.

Again, organic growers do not have many choices. Out in the field the biggest choice is whether to spray or not spray. As far as the value of the crop and in general, often times my wife and I will go out and see aphids just covering these plants but with closer inspection 60-70 percent of those aphids have mummified already and there are other beneficials crawling all over the place. Ignore it at that point, they are not doing any economical damage at that point. They are going to be under control next week. It seems to work.



[Editor’s note: A list of suppliers of beneficial organ-isms can be found on the web: <http://www.cdpr.ca. gov/docs/ipminov/bensuppl.htm>. The URL for the Koppert web site is: <http://www. koppert.com/>.]

Q: Can you talk a little bit about your cutting garden? Tell how it enhances your stand and then how you sell the flowers to people.

A: When we very first started selling at farmers’ mar-kets, the first year we sold things I raised some apples and the lady at the stall next to us always brought flow-ers. It didn’t matter if it was a rainy week or whatever. Some weeks we would sell our apples, some weeks we wouldn’t. She always sold her flowers. My wife loves flowers. She said, “I am doing flowers.”

Ever since we started a little garden a few bouquets of flowers have been part of what is for sale on our stand and then we have gone into this pick your own thing. Over the years we have found that pick-your-own vegetables is almost more trouble than it is worth. There are a few crops that I think are valuable, some of the greens, some of the herbs but a lot of the stuff is almost more confusion and more hassle than it is worth. We have always had a cut your own flower garden right out behind the farm. We work pretty hard to keep it looking nice.

It is a funny thing but the customers who are coming to cut your own flowers are just wonderful people it seems like. We will have wedding parties out there, we have mothers that come in to the shop whose daughters are out with some scissors cutting a small bouquet. What does therapy cost $40-$70 an hour and these people will just hang out there for an hour and cut five or six stems. They love it, they don’t trash the place. Once in a while there are a few flower species we grow that are too valuable to sell with the rest of them so we hide some of that, but for the most part they are there and we have learned after listening to a lot of talks that cut-your-own flowers are a part of a lot of farm operations and how you sell them.

The way you sell them is you sell them by the pound like everything else. Develop a price. The customer comes in with their bouquet, they take them out of the pan and you do not have to sit there and count each one out. Put them on the scale, $7.00 a pound and out the door. Wrap them up and they’re gone. We have been doing this for at least four or five years but I heard that

this was the thing to do by other flower growers that have been doing it longer. I am surprised frankly that most people do not know about it.

It has been talked about at so many meetings that is really the way to sell the flowers and to a large extent, flowers are not like food. People do not have to buy flowers, they want to. They don’t care what they pay. It really “pisses me off” we’ll be a nickel higher than the place down the street and the customer will go there instead. The same guy will be in in the fall and spend $100 on a couple of pumpkins and cornstalks, Indian corn, whatever. It doesn’t matter it is not food. Food is cheap. It is an ongoing battle and you guys are all organic trying to get the value added and that extra money but it is an issue that doesn’t go away.

With the flowers you keep it simple, come up with something that you think is fair by the pound but re-ally think about it. We will make an arranged bouquet that I think my wife sells for $12. It is a big bouquet, a little on the pricey side but it takes a bunch of time. It is not just a group of flowers; it’s an arranged flower group. We also sell by the stem so they are sold retail. So she just takes some of her flowers, she knows her time and I think she has come with about $7-8 per pound as what we are currently charging for flowers.

All of you people that are doing pick your own. Flow-ers are not the same problem so I encourage, especially if you like flowers. It is always nice. They were talking about having nectar sources. Goldfinches love cosmos. You get a row of cosmos and there are goldfinch flying all over the place. Having flowers in your operation, you can think of it as a money source and as a food source for your beneficials. That is a good way to do it. Any more questions?

It is hard as a farmer and some of you hopefully will get asked to come to speak at some things. Get over it and get up here and do it.

Q: What kinds of flowers do you grow?

A: It is all the ones that grow easily – snap dragons, cosmos, marigolds, zinnias, asters. Asters are a little bit tough, but we grow a bunch. We do a bunch of dried flower stuff too – straw flowers, statice and we do lark-spur but we grow that somewhere separate because it is so light and so valuable. Lisianthus is a flower that I love. It is a little bit difficult to grow, I buy plugs



and baby them. They go into a separate place because Lisianthus can sell for $1 or so a stem, just a single stem at wholesale. At $7 a pound you would not make enough money, but as a cut flower it can last for two weeks in a vase without changing the water. There is a lot of good resources I am sure on the web. There are cut flower associations. There is a lot out there. Some of it is what you like. Some of it is what fits into your operation. It is kind of unlimited.

Next year, there will be some talk on cut flowers at the New England Vegetable convention. It is a popular subject of a lot of us, especially the retail or direct retail type markets. Like I say, you bring some bouquets along with you to farmers’ markets and watch those bouquets sell. If you ever do some cost equations on amount of money you make per acre for the same

inputs, flowers will be way, way up there compared to some of the other crops that you grow and struggle with.

Q: Are your flowers organic?

A: No, they are not. Probably the only thing they are not is the potting soil. Whether or not you are getting some of the people who are starting to produce organic transplants for people. Whether you can get them to do some Lisianthus. It is a tricky one to germinate. This is part of the flower and part of the greenhouse operation. I order some Lisianthus trays in when I am buying the rest of my stuff. We do not start those ourselves. That is a new problem for you guys. They will have to stick to that for that government mandated … never mind – I won’t go there!



My wife Jane Sorenson and I farm in northwestern Vermont. We bought the farm about 11 years ago. Before that I worked a little bit at U-Mass research farm and before that I spent a little time at Cornell so I got to know Abby and what not, so it is kind of fun to get back and see old faces. We have an old dairy farm, about 150 acres and we grow about 40 acres in vegetables and then some strawberries and then cover crops and straw. We are located right on the Lamoille River which drains into Lake Champlain. I am very close to New York State, I am probably only about 15 miles as the crow flies from Plattsburgh. We are in the Champlain Valley so while we are fairly far north our climate is pretty decent for vegetable production.

As I go on in terms of the pest stuff you notice I talk about being far north actually in terms of organic production I think we have a lot of advantages. Right now we have about three acres of pick-your-own straw-berries. Those are not certified organic, they are IPM managed. We have got it down to approximately one spray for tarnished plant bug with a Malathion typi-cally and anything else is certified organic. These are some of the crops we do, a lot of kale and collards. A lot of these are switching as market kind of influences our change. We do a lot of winter squash still. Our leaf lettuce is changing completely, we are doing very little. Cabbage and carrots are big and greenhouse and tunnel tomatoes are getting bigger for us.

Here is a picture of the farm. Again it is all river bottom land, sandy soils, not a stone on the farm and we have about a mile and a half of river frontage so irrigation is pretty easy. We looked for a long time. Everyone says we are lucky. But it is not all luck. It took us about three years to find a place suited for what we were looking for.

There is the river, Lamoille River, that is high spring, it will flood every once in while and we have had some problems with that, but water is usually not a problem for us to get. There is some of the bottomland you can see and it is all sandy hills up on the right and all bottomland and the river just kind of follows the whole farm. Apologies for some of the photographs, some of these are actually slides taken of pictures so they are not exposed just right. This will give you an idea of the place.

I will just start going through the crops that we do and kind of the pest problems that we have and what we do. We do a lot of bedding plants and that seems to be growing. Like a lot of you probably we are getting suburbanized and houses are being built all around us and we said well, I guess we just need to take advantage of it. So, we started to get into bedding plants and it keeps growing and becomes a bigger part of it. As the former speaker was saying, people will pay whatever for flowers and whatnot. We said we can’t fight it, we might as well join it.

Pest Management from a Farmer’s PerspectiveTranscript of a presentation by:

David Marchant River Berry Farm Fairfax, Vermont



My wife runs this operation pretty much. All of our greenhouses are ground to ground greenhouses, fairly low tech. We kind of got into it cheap and as the years go by, when we put up houses now we do it a little bit better each time. When you are first getting started it is hard to put up a full range. In terms of pest control we make our own mix and this is a soil mixer that we bought out of Canada. It is a pot filler and soil mixer. We make our own compost and we use along with about 30% compost, peat and vermiculite mix. We simply put the pots here, there is a foot pedal that you step on and the mix is in here. It mixes a yard at a time. We do a lot of flats for our field production so it is a fabulous machine and it is really reasonably priced.

It is interesting, you look at a lot of the equipment and it is for big operations and there are some places in Canada that actually make smaller scaled equipment that really is suitable for operations like ours. Instead of $20,000 it is more like $7,000 or $8,000, so it became fairly cost effective.

We use T-22, it has been talked about a lot, in all our mix. It is hard to say, we were using compost in our mix, and maybe we are throwing money away but it just gives us a consistency in terms of damping off problems. Sometimes we have inexperienced people watering and we get overwatering happening and we seem to prevent a lot of soil problems by using the T-22, so we use it in everything and it seems to work very well for us. It is not cheap, but with the mixer it is easy to mix in so it is right there in the mix so as soon as you water then you start getting the effective-ness from it. This is some of the plug production we do. We vacuum seed, we do a lot of brassicas, a lot of kale, collards, cabbage, about 10-15 acres total of those crops and this is it where we are just setting up and germinating. We even use T-22 in all our field transplants mixes as well. This is when we first got started, before we even had decent benches. A real mixed hodgepodge of field transplants.

One thing I would point out is the old window fan and we now have HAF, but in terms of disease control I swear by HAF fans and air movement. Our next big crop besides bedding plants is tomatoes. For us toma-toes are greenhouse tomatoes and tunnel tomatoes. Some of our major pests that we have to deal with are different than field tomatoes. We are fairly far north so there are a lot of people that do produce field tomatoes but we are starting to pick about the third week of June

and go right through until Thanksgiving and it really works out well for us. We just don’t even deal with field tomatoes except for some paste tomatoes I put in for myself.

Our major pests are Botrytis, Fusarium, root problems because we are in houses that do not necessarily rotate out every year we can get some root disease problems. Whitefly as well. You can see some of the things that we do and I will show you some pictures of stuff that we do. For Botrytis, actually I picked up some tips when I was at this conference a couple of years ago and they talked about sanitation of the complete house that I hadn’t thought about. We use OxiDate as well and I just got information from BioSafe who produces it and it is not NOP approved but they are reformulating it to get rid of the inerts and there will be a product this year that is available. We actually spray the entire house with OxiDate, the plastic, the metal, everything, just to get rid a lot of inoculum. It definitely seems to be making a big difference. That as well as proper ventilation. Root rot problems can be a big problem in greenhouse tomato production and we have gone to grafting. We graft all our own tomato plants now. It is a very simple system that we got out of Canada.

It is funny because we are a real anomaly, everyone milks cows and you are not a farmer unless you milk a cow in Vermont, but you go across about an hour north and there is about 20,000 acres of vegetable production just southwest of Montreal. So, there are a lot of resources for us. Some of the resources are the greenhouse tomato facilities and it is a very simple sys-tem of producing a root stock that is resistant to some of the diseases and a desired top and just using these little plastic clips and cutting them with a little razor blade. You’ve got a tray of tops, you’ve got a tray of root stock and you put one on top of the other and you can see a nice grafting right there. You just put the clip right over the graft and we put them in the hoods and that is the key right there, these high domes, it keeps the humidity high and we probably get 85-90% take. It is a very simple, quick way to do it. It works well. We do it for root disease problems, Fusarium. Some of the root stock of the greenhouse tomatoes the vigor is unbelievable, you get higher production, they are a lot more tolerant to a lot of the root disease problems and we find we get a lot longer life out of our tomato plants with the grafting.



Question: What rootstock do you use for your greenhouse tomatoes?

We have gone to Beaufort, we used Kyndia which you used to be able to get out of Johnny’s and I have a catalog that is called Group Horticale le Doux, I have the seed catalog here out of Quebec and we have gone to Beaufort and they have another one coming out this year that we might try. It is just amazing, these things are like trees. It is unbelievable. So, we put everything in to a four inch pot.

Here is one of our greenhouse tomatoes, very small, simple houses, 25 ft. houses, 25 ft. x 150 ft. We run eight rows, you can get two rows per bed, but this is the way we try to get it really clean, spray the whole thing down. You can see we use these HAF. These are cheap HAF out of Grainger’s. The plastic ones are about $45 instead of the typical $140 and if you look at the specs they are identical to the metal ones. When you start putting four or six in a house it saves you a lot of money. You can see we are getting ready to plant. We typically use T-22 in the soil, to just to give it a little extra protection. This is actually not our house, but this is how we do it, growing them on string. We have a lot more pathway than this. This is a little tight, but we just wanted to show you. I do not have a lot of great slides. I haven’t taken a picture in about five years it seems like. We do trellis everything up on twine, as well. Everything is shipped out. We wholesale everything in to the Burlington area and we just have two stores that will pretty much take everything we can grow and we sell at one farmer’s market and that is about it. The nice thing is we have a small stand with the pick-your-own strawberries and the farmer’s market we can send all the B-product. We hardly throw anything out. Last year I don’t think I threw out more than 100 pounds of tomatoes of overproduction, because we just couldn’t keep up, so it is something that is worthwhile for us and pest-wise we have been able to deal with it.

The other thing I talked about is we introduce a lot, we do use Encarsia for whitefly and for aphid control we often use the Hippodamia, the lady bug that is pretty cheap to start with and also if we see a hot spot we may bring in lacewings, some of the more expensive predators a little bit, but we scout and we use yellow sticky cards within the houses to monitor for whitefly. We are doing that in the bedding plant houses, so it is kind of a progression. We start the bedding houses in

February, we plant the tomato houses late March so we know if we are going to see any whitefly it will tend to show up first in the bedding plant houses, so we really keep a tight eye on that because they tend to move from one house to the next. The nice thing about being far north, I kind of pray for those –20 degree nights because the houses get to be –20 and a lot of things just don’t like it that cold. The other thing that we do a lot of is we have a controlled temperature room, we keep it right around 50 degrees so if we get long, we can hold them, we are picking them at a breaker stage so we can hold them. It is a nice crop, you have a lot of control, and flavor wise people seem to love them. I know field tomatoes some people swear by, but we go this way.

The other thing we do is tunnel tomatoes: unheated greenhouses. I am sure a lot of people here use kind of walk in tunnels, no heat, roll up sides, cheap struc-tures, throw a piece of plastic on it. We like to use Ultrasweet in these and we typically do basket weave trellis system. Something like that – four rows, drip tape and you walk away and come back once a week and string them and pick tomatoes. A very good way to go. We start in March with our greenhouse tomatoes and then we get this big production June or July. When they start to slow down these tunnels come in and we actually rip out an old bedding plant house and plant another crop in mid-July so we get a really nice fresh crop coming in September and October. The reason I do not grow tomatoes outside is because in the green-house we never have any early blight, we never have any Septoria, we never have any disease problems like this (slide). We don’t have to grade through our tomatoes. We pick right into the boxes, number ones, number twos. Botrytis we do have to deal with. A little bit different pest complexes that you have to deal with in the houses and the tunnels, but you keep your leaves dry and I don’t grow field tomatoes, that is basically what it amounts to.

Question: What is T22?

T-22 is a Trichoderma product that is produced here in Geneva through BioWorks. We get it through Griffin Greenhouse, but Seedway has it as well. It is a ben-eficial, soilborne fungus. It is actually a protectant in a lot of ways, competitive protectant, it will compete at infection sites, so in other words it can out compete Pythium or some of the damping off things and also I will talk about its use in strawberries a little bit.



Pick-your-own strawberries

Next crops – pick your own strawberries. They are not certified organic. I tried a number of years with differ-ent organic blocks in terms of the tarnished plant bug and I have still not come up with a successful way to control them. We have got it down to about one spray, but you can see here some of the pick-your-own straw-berry fields. We don’t do a lot, we can only really sell about three to four acres of pick your own. We have a lot of other people growing them around us. It is a good draw and it is part of our farm name so we have to grow them now, I guess.

We are starting to play with plug production and an-nual strawberry culture, plastic culture. I am sure a lot of you guys have heard about this. I am talking about strawberries, I know it is a vegetable workshop but I did look at my New York survey of vegetable crops and strawberries are listed in the vegetable section so I figured it counts. I know a lot of vegetable growers grow strawberries. We have been playing with this plastic culture. It is interesting.

Different pest problems. We get some different soft rots on the fruit where it is laying on the plastic. An-thracnose seems to be a little more of a problem. It is an interesting system, I think it doesn’t work for pick-your-own because it is a very spread out type of ripen-ing system that works great I think if you are trying to use it for planting for a retail operation, picking and resale. We have tried to send some pick-your-owners into the plastic culture and they kind of walked around. You get a berry here and a berry there and it produces over a very long period of time, but they were a little frustrated. It is kind of a fun way and it is a totally dif-ferent way and you can get high production. They keep quoting these huge numbers down in New Jersey and as you go further north it seems to be less and less. I think it has promise and a lot of growers in Vermont are playing with it and we will see where it ends up.

You can see there we are using row covers. There is talk about row covers that Ruth talked about and we have gone to the plastic bags, sand filled bags and we really like it. For some reason it just does not blow up out of it like a shovel load of dirt. Even though it is not secured everywhere it just doesn’t move and it is amazing how they work. So we will just go down with an apple bin full of bags and somebody just plunks,

plunks, plunks as the tractor goes along. It is a really quick easy way to do it. We had it set up there for the annual culture strawberries. We do some trap moni-toring for tarnished plant bug in strawberries. We use these white sticky traps just to get an idea when they are flying. It is hard to say. Some people say they don’t work, but it is nice to be able to go to a spot and say, oh, they are there now, I better start trying to pay at-tention to them. As I said, we play with a lot of ideas.

Here we are releasing a predatory egg parasite of tar-nished plant bug called a Anaphes iola and they use it out on the west coast for organic strawberry produc-tion. The problem is we are shooting in the dark. We use their release rate. It is fairly expensive and we just don’t know if it is working. I would love it if someone could pick it up in the east and start working on it because with biocontrols it just takes a lot of research and a lot of time and it is so different out in California that it is hard to know if it is really working. We tried them a couple of years and I really did not get satis-factory control, so I stopped spending the money and said once somebody starts really researching it maybe we can go back to it. I think it has promise, but it is a parasitic wasp and it lays its egg inside the egg of the tarnished plant bug so it is a nice stage it is attacking it in. The nymph is what we get most of our problems from. It is hitting it before the pests can cause a lot of damage. That is why I think it has real good potential.

We do grow a lot of our own straw. There is a rye vetch crop and we just have it custom combined for us; it seems to be another way to avoid some weed pest problems. Not insect and disease pest problems, but by growing our own straw either if we combine it or sometimes grow it to seed head stage and cut it and bale it that way, so that we do not get seed production. Then you do not have any kind of volunteers at all.

Vegetable crops

Next on to some of the vegetable crops. Leaf and romaine lettuce. This is what we used to do and the wholesale prices have kind of been pretty dismal. We are doing less of this, but typically what we would do is start in late April and we would plant every week until about mid-August. Three rows per bed, 18 inches between rows, 15 inches between plants. It is fairly wide spacing. It certainly helps with disease problems.



Our major pest is Rhizoctonia bottom rot, it is always a problem for us. We rotate which seems to help. We are using raised beds now. This past year we had very little problems and we had real high raised beds. Who knows if it had anything to do with it. We tried using T-22, watering it in, seeing if it would be a protectant. In other words if you could get it growing down there it would out compete the Rhizoctonia and I don’t know if it works or not, but we have tried it.

Other major pests – tarnished plant bug is a major pest in the summertime in lettuce so we try to hide. In other words we move it around some if the plantings and I often think that sometimes you just have to assume some large losses on one or two plantings. You don’t know which one it is going to hit, but if you are trying to have a consistent market you just kind of figure that is going to happen. We tried not to do much romaine towards the mid-summer, late-summer and fall when they really like to hammer the ribs a lot.

Aphids can be a problem. We have had them flare up in the late summer and we have had luck with the neem product. That did seem to work. Downy mildew is also a real problem with romaine and we just stopped growing fall romaine. It seemed to be a better solu-tion that trying to fight it all of the time. Tip burn is the other big problem and we try to irrigate regularly, try not to let the soils dry out and there is starting to be a lot better breeding work now in terms of tip burn tolerance. Some of the romaines now seem to be better and some of the green leafs. I just love growing red leaf, because all of the problems just seem to go away. It doesn’t seem to have nearly the problems and so we tend to concentrate more on red leaf.

The other big problem is deer and we use portable elec-tric fencing. One thing we have played with is lettuce produced in a tunnel. This is like the first of May and you can see green leaf and red leaf here. We were able to get $1,500 out of the tunnel on the real early lettuce and then we were still able to use it for tomatoes right after it. It is a nice way to get some extra usage out of your investment. Here we just had overhead sprinklers. So, we had very little labor. Here we are transplanting. We use a carousel planter a Lännan planter, it is a great transplanter. This might be onions, but we actually use it for everything and lettuce right now would be three rows. Everything is on three rows, 18 inch spacing. Our cultivators are set up for one spacing and we try to keep them that way. Here is a lettuce field you can see

green and red leaf planted. Our raised beds are actually higher now. We have a better bed shaper.

Deer fencing

Here is some of the deer fencing. Here is a field you can see getting ready to be cut. We have a lot of prob-lems with deer. You can see we have a lot of woods around us and they would love to come in. I went to a guy who specializes in fencing and we started with these tall white posts, New Zealand system and went with seven strands. It really did work. I put them out at an angle and we baited them with peanut butter on aluminum foil and now I am down to just two strands.

What I have discovered for our deer pressure and I know it is a lot different in parts of New York State were it is really heavy, but, I have dealt a lot with deer and what I have discovered is that if it is changing they won’t get used to it and cause you problems. So, in other words we will come in and protect this crop and as soon as it is harvested we will move the fence. We spent a lot of money on a permanent fence around the whole field and it was a total waste of money because they got used to it and I didn’t maintain it and they just plowed right through it. But, you put these things up and you are in and out. It seems to me visually they can see this, this white thing and they associate it, you know, they lick this once on a nice wet morning and they get a good shock and they just don’t seem to tolerate it. In fact I can even turn the fence off and they don’t even bother it. It seems to be the key. If you leave it up all season then they just ignore it and start plowing through it. For us, the key is to move it. So, this is what we are down to. Two strands and some peanut butter on aluminum foil.

Field packing

Here we are field packing. We field wash. The ef-ficiency of this is marginal. I would say it is more ef-ficient than taking it all back and washing it, but I think for us to be able to compete on a wholesale market to do lettuce you really have to pack directly into boxes and use hydrocoolers to beat the prices and we just decided it wasn’t worth the investment. We grow it now for more local markets and every once in a while



if we get long we can ship it to our co-op. Here we are field washing. We are able to do a good job with field washing, get it cool and get it into our cooler so we can pick a field, keep it for a week and sell it out of our coolers for a week which is a big advantage for us. We try to concentrate a lot on post harvest cause I think it is a real important part and it makes life a lot easier and the quality of our vegetables a lot better.

Greens

Another big crop for us is greens. It is funny, I was talking to Ruth and all the things she talked about are all our problems. I will tell you what we do. All the same things.

What we have gone to is we grow collards, kale as soon as we can put them into the ground until we stop picking them around the end of November sometime. Again it is everything three rows per bed, 18 inches per row and 18 inches in the row. All this early spring stuff we plant it out and we put wide row covers over it right away. It is the first thing we do. For two rea-sons, one for cabbage root maggot and also for flea beetle. The cost of the cover is fairly expensive, but it certainly warrants it for us. Another thing that we have done sometimes is to just not even worry about weeding that crop and go in and cut that first crop and then have another planting behind it that we tend to maintain a little bit and we are able to not have to use a row cover quite so long so that we don’t have to take it on and off so much. That was one thing we have had success with.

We have a lot of imported cabbage worm. I use Bts and I use a lot of Bt. That is pretty much what we do and I am really excited about this Spintor maybe we will be able to rotate it because I am starting to worry about resistance, especially with diamondback. Dia-mondback is another problem we have. Flea beetles are a problem, they used to be a major problem for us. I think since we started using the row covers and listening to what Ruth said I am starting to think that we are not getting the big population build up and I used to spray a lot rotenone and I don’t spray it at all anymore. I know I am killing a lot of beneficial with it and I guess now I can’t even use it with the new NOP standards. The flea beetles have come into more of a balance. For what everyone says I was always a little

bit skeptical, but after being on the place ten years and managing the place I definitely see some of the pest cycles, the pressures reduce in general and more of a balance coming on. We avoid a lot of the early flea beetle. We do get some of that second flush that Ruth was talking about but it is never super severe. It has become much less of a problem for us. Club root is the other problem and we have it. We try to keep our equipment clean from field to field, but we do not do a great job of keeping all the mustards down. We are starting to look at using lime to try to get the pH up to avoid it because it is definitely a problem for us.

Cabbage

Cabbage. I am going to go through all the greens and then I will show you the pictures of how we grow them. We do a lot of cabbage. Everything is trans-planted. We do not direct seed anything into our field in terms of brassicas. It gives us a head start in terms of weed control. It gets the plants out there growing before pests can be a major problem. We transplant every two to three weeks starting in early May and then we transplant storage cabbage end of June. Actually I have gone to planting cabbage until about August first just using with short season fresh market stuff to carry me through more on a weekly basis instead of trying to time different late season cabbages and having them all come on too early or too late. I have gone to something like a Columbia, like a 65-day cab-bage, a nice fresh market cabbage, that we can just plant every two weeks and we get a nice consistent supply and then we will put in a fall storage cabbage that once we are done with that crop we can get into. Major pests—same thing. We do have Alternaria problems sometimes and we just rotate. I would say the number one disease thing we do on our farm is rotate. It is the first thing we can do. We would never consider planting brassica upon brassica.

Broccoli

Broccoli, we don’t do a lot, a few acres of broccoli, we don’t transplant it until about mid-July. We really only go for the fall crop mainly I don’t want to deal with tarnished plant bug problems, all the brown beading that you get. It is probably one of our major insect pest that we can’t deal with real well. We can deal with imported cabbage worm real well and then head rot we just got some nice Rise, Everest and Marathon, some of the nice really tight beaded domed head varieties



that seem to do really well against head rot. A little bit about how we prep some of the ground. This is a rye vetch cover crop. When I was talking to Ruth I think it might be part of our tarnished plant bug problem, too. I seems to build up a lot of tarnished plant bug. We use it everywhere on the farm for a nice plow down and a soil builder but you get into these systems and you start to realize it effects other things as well. Here we are transplanting collards again using our plug planter and my sister and her kids were up visiting. The nice thing about these transplanters is that very young people can use them and they love to do it. Some of our major pests you can see there imported cabbage worm, some of the damage. With collards and kale, Lacinato kale, especially, they love and you can’t tolerate hardly any damage. You just can’t ship it and because we are shipping a lot to the supermarkets in Boston and Philadelphia and DC we really can’t toler-ate much damage. We are on these spraying quite a bit, but that is what it can look like and if it’s like that then it is too late. Cabbage root maggot you can see when it happens and that is when we really avoid it with the row covers and after that it doesn’t seem to be a big problem for us. Club root, you I don’t know if you guys have all seen club root, but his is what it looks like. It is not very pretty and it can really devastate a brassica planting pretty quickly. I think we are going to start concentrating more on liming and I have kind of just tried to keep pH on the farm general in the 6.5 range. I’m realizing now that I have to be a little bit further ahead in my rotation thinking and plan where I’m going to get brassicas and try to get the pH up.

I’m starting to do some dense planting type stuff for crown production instead of head stuff. But again you get into these tight situations and you get some other problems, that’s another way of dealing with problems is getting a crop in and out quick so while you may be tight and you would certainly get a lot of head rot if you let these things mature, if you get in there and cut them out quick. It is a way to avoid those disease problems.

Head rot on broccoli (slide). I’m sure everyone has seen that.

Here we are, I’m not sure what we are harvesting here. Greens, I think collard greens but we use a harvest conveyer on all of our cabbage and we pack right into boxes as well as, we used to use it on greens. A lot of times now we just send pickers out with boxes and

they pack right into the boxes. We use it on broccoli as well, but it is a nice way to facilitate harvesting and make it go a little bit quicker.

We ship a lot of our brassicas through our grower’s co-op. We belong to a co-op called Deep Roots Organic Co-op. We have about 12 farm members and we ship under one name and we ship into supermarket chains: Whole Foods, Fresh Foods, Albert’s, what used to be Northeast Co-ops which is now United Natural. It is a good way for us to sell quantity but what is happening is I think I am getting less now for my collards then I did ten years ago through the co-op. I am starting to rethink how much emphasis we put on our wholesale especially as we are able to grow some of the retail end of our operations. Even though – I think we are doing very well with our local wholesale situation. We have a lot of interest with organic product in Burlington. Having some of this kind of stuff really makes a big difference on your product. It really makes it stand out and looks nice and people seem to like it that way. Everything gets iced here – you can see ice on top of all the greens, they go into the coolers and then they get shipped out the next day. With this situation we can keep them in here for five to seven days and they would still be beautiful. Post harvest is a really good place to do a lot to make farm management easier. I like post-harvest it is one of my favorite parts. I think I can improve my yields more in post-harvest than I can in a lot of other places. It makes the flexibility of marketing a lot easier.

This is an old dairy barn, an old five stall barn we put coolers in. It is a pretty low-key operation, but it works. The problem is low head height but we deal with it and in hindsight it would be nice to put up a new building but it is all in place so we use it.

Cucurbits

Another big crop for us. Cucumbers, we do winter squash, anywhere between five and ten acres. It de-pends on the year. We do some melons, but a small amount. I sound like Steve because we have had some good years of direct seeding winter squash, like last year I said, “Oh, great, my buttercup did so great the year before I am going to do it again” – now I swear I am never going to direct seed any winter squash, we are just going to transplant. That is how we deal with



striped cucumber beetle. We just transplant in mid-June and it seems to make a huge difference. I am going to do it with our pumpkins now, too. It is just so easy and so quick with our transplanter to plant an acre. You get such an even stand. Weed control is so much better and with the striped cucumber beetle it is really a big advantage. I use a dust with 5% rotenone. I have a backpack duster and then that would work okay. I have gone to a coffee can or a sock because you can hit each spot. I think we might try doing some of the trap cropping and transplanting to see if we can get away with just the spot treatment.

Powdery mildew is a problem. We are starting to use some resistant varieties. I love Tay Belle it is a great acorn variety, Athena is a real good one, too. It makes a big difference with the melons. I would say powdery mildew is more of a problem with our melons and our winter squash by the time powdery mildew comes into our winter squash we have pretty much matured our crop. Climate wise we can not produce the secondary flush and get things to mature. Most of our fruits are mature by the time mildew really becomes a problem whereas the melons – it can seem to take them down relatively quickly. I have tried some of the potassium bicarbonate sprays. I am not sure how effective they are because I can’t get coverage on the underside of the leaves, but again with the way Steve said, it is there, I know it is there, it probably reduces my yield some, but we just don’t spend a lot of time managing it. Bacte-rial wilt is a problem. We row cover our melons and that seems to help a lot to get them far along before striped cucumber beetle comes in. They are on plastic as well. Post harvest is real important. We try to store our winter squash at 50-55, we also try to sell out by about mid-December. That way we are able to kind of reduce our losses in terms of post harvest.

We used to plant on plastic. I have gotten away from plastic on winter squash but here is a nice transplanted crop. They just grow so quick once you get them on transplants. It is that cotyledon stage when striped cucumber beetles can just wipe you out. So we just decided we are just going to transplant. It does take up some greenhouse space but you don’t really need hardly any heat. We use the edges of the tunnels to do it and it works pretty well. You can see our melons on plastic. Again, they will be row covered. They are this big before we take the row covers off. Powdery mil-dew, again, it just doesn’t seem to be a huge problem in terms of how we grow our cucurbits.

Sweet corn

We grow about seven to ten acres of sweet corn and we grow certified organic sweet corn so we can actu-ally ship a fair bit. There is a fairly good market on the organic end because there is very little competition and the reason we can do is because corn earworm is really not a major problem with us. We will get it blown in every once in a while but we haven’t gone to the Zealator applicator primarily because we are not getting the real big dollars for it and time wise with the amount of pressure we have I am not sure it is worth it. Corn borer we have gone to using the wasps that everyone has been talking about. This is our first year and it seemed to work quite well. We do spray with Bts and with the raccoons, another big problem, we use a portable electric fence, one strand. Another issue now is the fact you can’t use any treated seed for organic production. We have now started to work with transplanting sweet corn for the early corn so we can get a decent stand. We can get very early sweet corn and we tend to just retail that. I would not wholesale any of that. It is a great way to grow sweet corn if you are haven’t tried it. We put two seeds per plug in about a 150 cell tray every foot. It is amazing, the corn may only be this tall but you get actually gorgeous sweet corn. If you got a good market for it is a good way to go and get a good early stand.

Earworm is what we don’t have a lot of problem with and I called Ruth actually this summer and said if it comes in is it around forever and then it vanished. It just wasn’t there again, so I don’t know whether not enough of it came up to be a problem. I hire a scout and that has been great. He is a friend who used to be an IPM coordinator in Michigan and so he has a small operation and we trade things and he comes and scouts my corn and my brassicas for me. He said it looked like we had a problem but it did not stay around for more than one planting. We scout for borer and spray for borer and we are able to keep it under pretty good control.

Smut – I hear it is a delicacy but have not tried it. This is a transplanted field of corn, a nice even stand that I took a picture of.



Corn varieties

One problem we have with a variety we love, Lancelot, it is extremely tender, it ships well, but you can get blow-down problems. This year we did have a real blow-down problem. This is an early blow-down. It was kind of a physical test problem for us. Variety selection is something to think about.

Sprayers

We use a boom sprayer. I do not use an air blast. Air blasts are good but sometimes you do not know where everything is going and I like to know everything is going right on my crop. We have gone to the pack-tank sprayer because it has a mechanical agitator. It has a shaft right through the middle of the tank and if you are using any kind of wettable powders it makes a huge difference in terms of keeping things mixed up. When we tried to use kaolin clay it seems to work well. I have also gone to being able to raise the booms and then I would put drops on this for sweet corn. It works out okay as long as the corn is not super huge. There is inside the tank. You can see the paddle. It turns all the time. It is always agitated. I have another sprayer that recirculates and agitates and it is not nearly as effec-tive. If you are looking a buying something and you are going to be working with some of these materials that don’t dissolve real well I really suggest these.

Potatoes

We grow a couple of acres of potatoes and what we do is try to get in and out quick. The years that they don’t go down with leaf hopper we get bigger yields and we market them for a longer period of time. We have often green-sprouted potatoes on the greenhouses and put seed potato in, green-sprout them and then put them in the ground, right through the planter and they really come up quite strong. You have a big plant before CPB is even around. It is a good way to get a crop and avoid some of the problems.

I would say our biggest kind of use of pest control on potatoes is avoidance more than anything. We had some real trouble with hopper burn. I tried rotenone on it without much success. At this point I really don’t use

any fungicide, any copper on the potatoes at all. We just get them in early, try to get a lot of growth, get what we can out of them. Market them at a high price early on and then if we get a big yield we will carry them on through the fall. Our biggest problem is Rhizoctonia or scurf, the black dotting that you get. What we have tried to do with that is to rotate as much as we can out of other susceptible crops like lettuce. We found this year’s potato crop was in where corn was and we had very little Rhizoctonia problem at all. I don’t know if that has anything to do with following corn but it is something for us to maybe try again. That is probably our biggest problem in terms of selling potatoes is our Rhizoctonia problem.

Root crops

We do about three acres of carrots, couple acres of beets and we are still shipping carrots now. The big-gest problem for us is Alternaria in the field. We have used copper every once in awhile. We try to use some resistant varieties and we can also get some storage problems with the cavity spot which I will show you as well. We direct seed everything with the Stan-hay seeders, pelleted seed so we get pretty good seed dis-tribution. Typical bed preparation would be disking and then field cultivating but that gives you an idea of some of the carrot fields. Three row, fairly tight which is probably perpetuating some of my Alternaria problems but it just works out pretty well for us. Everything is on raised beds and it has been a really good crop. We have a very good market for it in the Burlington area. If I had to try to ship against California all the time it just wouldn’t pay.

Here is the Rhizoctonia, which we get problems with in storage. What we have gone to now in our coolers is we actually mist completely. We do a lot of purple top turnips because we can machine harvest these. They are fairly efficient for us in terms of being lucrative. Beets, specialty beets, chioggia beets, gold beets, some of the things we can wholesale into supermarkets at a fairly decent price. They all store very easily. Our pest problems are very minor on these. I think it is a big reason we choose to grow what we do because we can manage the pests.

There is an old time carrot harvester that we use on beets, turnips and carrots. We store everything in



bulk bins and then we mist our rooms. We actually have misters in there to try to keep the humidity up. That has definitely helped a lot. I would like to go to plastic bins if I could afford them but that is going to be a few years down the road because I think we do probably have problems from year to year with some of the wood bins. They do store quite well in here. What we are packing out now is pretty nice product. We have a small packing house in the dairy barn. We have a barrel washer and we run a few people during the winter time a couple of days a week and we pack out cellos, then we put out a bulk product that gets shipped to local health food stores. We have a couple juice bars that take some of our products. People seem to love our carrots because they are very sweet. We harvest them late in the fall so they develop a lot of sugars and for some reason it is one crop that people just love what we grow.

With beets it’s the same way and it’s a very easy crop to wholesale. It is amazing how much demand there is for cut beets. That’s it, I guess. Any questions?


Q: When you store carrots is there any sawdust or anything surrounding them?

A: No, no, but they are in the bulk bins and they are in the coolers and we try to keep the coolers as close as we can to 32, 34. Right now they are in our barn. I don’t even use the coolers, I can kind of keep the barn just at about the right temperature because it is half buried in the ground and then I mist to keep the humidity up.

Q: What kind of price do you need to make money from sweet corn?

A: We wholesale 4 dozen for about 48 counts for $15.00. So I probably see $12.00 by the time subtract my trucking and my commission and things. What I use a lot of my wholesale thing for, I will sell my lo-cal retail for $3.50 a dozen and then I can retail it for maybe $4.00 a dozen and then if I am long I can ship it down to Boston to the supermarket. So I kind of use it that way. The reason it makes money for us that way is because we have no labor into it except picking it. I plant it, I field cultivate it, we don’t hoe it. We have

spent a lot of time analyzing how much labor, we track all the labor we put into each crop. Our workers fill out a time sheet with the number of hours they work on each crop. Sweet corn is a really good ratio in terms of labor input to what we get out. From a per acre basis it is not real profitable, I can’t really make more than about $1,500 an acre probably from it. From a labor cost standpoint it is really good.

Q: What does tarnished plant bug damage look like on lettuce?

A: It is right on the ribs and it pokes in it. Have you ever seen it where it gets really corky on the ribs? That’s tarnished plant bug feeding.

Q: Is it the nymphs causing the damage?

A: No it is adults. They are in there, you just open it up and they are all in it.

Q: What does tarnished plant bug damage look like on broccoli?

A: It’s the brown beads. Have you ever seen the dead beads? They will feed on the bead and the adults will feed on the bead and you get brown bead and it seems to be a bigger problem for us in the summer time. You know the first cutting in late August and early September we will see some and then it just goes away.

Q: How do you make the beds for your carrots? Is it a two step deal?

A: Do you mean two passes? Well what we do, you saw the disk and we use a light field cultivator and then we will go through with the bed shaper and our bed shaper usually has to go over it twice to get it perfectly smooth. Yeah, press pan type.

Q: What’s your favorite early sweet corn variety?

A: I like Aladdin out of Stokes. I don’t think I am going to be able to use any more because I can’t get it untreated. But now that I am transplanting early corn, I can go into a little bit later varieties so that I don’t have deal with really short ear ones. So I’m trying to think of some of the names. I use Mystique as my second one and then Lancelot quite a bit, also Trinity is a pretty decent type ear for an early one that if I transplant seems to do OK.



Q: Which of those varieties is the most vigorous grower?

A: Mystique is an awfully good grower I think. I am not an expert on corn varieties though. I’m kind of new at corn. I have only been growing it about four years. Now with the new NOP standards, in Vermont we could use treated seed so what I could get un-treated late in the season I would use it, but now I’ve got to really source that out. Lancelot I really enjoy and Seedway does carry that, even though you do get some blow down problems. I have found that if I got some other varieties around it, it doesn’t seem to blow as much. It is just so tender for so long the tenderness is throughout the plant so not only does the ear stay tender but the stalk is very tender, and that is why it tends to blow down.

Conclusion

Just a couple of resources. This is my bible for diseases and pests of vegetable crops. It is Disease and Pests of Vegetable Crops in Canada and it’s got every picture that you would want. It covers greenhouse tomatoes and greenhouse cucumbers as well. The nice thing is I don’t have to go turn the computer on and try to fire up a web site. It is just right here and it is all in one book. I can leave it out here if you want to look at it, it is available through the University of Vermont, Anne Hazlerig, Hills Building, Burlington, Vermont. It is just a really good compilation. Certainly, all of the stuff from Cornell is available but it is not all in one spot that I have been able to find. The other thing is the greenhouse tomato group, I have got the seed catalog here if you want to look at it or get an address.

Thanks for having me.


About NRAES

NRAES, the Natural Resource, Agriculture, and Engineering Service, is a not-for-profit program dedi-cated to assisting land grant university faculty and others in increasing the public availability of research- and experience-based knowledge. NRAES is sponsored by eight land grant universities in the eastern United States. Administrative support is provided by Cornell University, the host university.

NRAES publishes practical books of interest to fruit and vegetable growers, land-scapers, dairy and live-stock producers, natural resource managers, SWCD (soil and water conservation district) staff, consum-ers, landowners, and professionals interested in agricultural waste management and composting. NRAES books are used in cooperative extension programs, in college courses, as management guides, and for self-directed learning.

NRAES member universities are:

University of ConnecticutUniversity of Delaware

University of MaineUniversity of Maryland

University of New HampshireRutgers UniversityCornell University

West Virginia University

Contact NRAES for more information about membership.

NATURAL RESOURCE, AGRICULTURE, AND ENGINEERING SERVICE (NRAES)Cooperative Extension, PO Box 4557

Ithaca, New York 14852-4557Phone: (607) 255-7654Fax: (607) 254-8770

E-mail: [email protected] site: WWW.NRAES.ORG