Building Soil Health: Why it Matters...Mites 65 Collembola 65 Earthworms 624 Other fauna 40 Pore...
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Building Soil Health: Why it Matters David Lamm National Soil Health & Sustainability Team, Leader
Building Soil Health: Why it Matters...Mites 65 Collembola 65 Earthworms 624 Other fauna 40 Pore Space SOIL IS HABITAT Food Water Shelter View the soil as habitat for microorganisms,
Biological properties - earthworm numbers, and other animal activities that are important in soil development and fertility, soil respiration, pitfall trapping, microbial biomass, cotton strip assay, soil food web structure, etc.
Ideal Soil Composition
{ }Pore space 50%
Solids 50%
25% Water
25% Air 5% Organic Matter
45% Inorganic (mineral materials)
Presenter
Presentation Notes
An average soil is composed of mineral matter, organic matter, and pore space, which may be occupied by air and/or water. The percentage of these four components can vary depending on how and where the soils were formed. 50% solids and 50% pore space; obviously, these are mixed in a natural environment and fluctuate greatly throughout the year.
Soil Health What is It?
• The continued capacity of the soil to function as a vital living ecosystem that sustains plants, animals, and humans– Nutrient cycling– Water (infiltration & availability)– Filtering and Buffering– Physical Stability and Support– Habitat for Biodiversity
• 90% of soil functions mediated by microbes
Presenter
Presentation Notes
Review the definition of soil health and function, need to remind them that this is goal of the planning principles This is the definition of Soil health we are using. The term “Health” was purposely chosen instead of “quality”. Quality implies analysis and quantifying Health implies management actions that leads to a condition or state, there is something that can be done to change it in a positive trend The key to the definition is that soil health is: Continued capacity—implies rejuvenation and then sustainability Soil is a living ecosystem– most folks think of the ground beneath them a living Soil function – soils need proved the basic function below in order for food & fiber production to be done and meet the demands in slide 1 Nutrient Cycling - Soil stores, moderates the release of, and cycles nutrients and other elements. During these biogeochemical processes, analogous to the water cycle, nutrients can be transformed into plant available forms, held in the soil, or even lost to air or water. Water Relations - Soil can regulate the drainage, flow and storage of water and solutes, which includes nitrogen, phosphorus, pesticides, and other nutrients and compounds dissolved in the water. With proper functioning, soil partitions water for groundwater recharge and for use by plants and soil animals. Biodiversity and Habitat - Soil supports the growth of a variety of plants, animals, and soil microorganisms, usually by providing a diverse physical, chemical, and biological habitat. Filtering and Buffering - Soil acts as a filter to protect the quality of water, air, and other resources. Toxic compounds or excess nutrients can be degraded or otherwise made unavailable to plants and animals. Physical Stability and Support - Soil has the ability to maintain its porous structure to allow passage of air and water, withstand erosive forces, and provide a medium for plant roots. Soils also provide anchoring support for human structures and protect archeological treasures.
Winter Pea Nodules 2011
Biomass of organisms pasture above and below groundOrganisms Standing crop biomass lbs./ac.
View the soil as habitat for microorganisms, just as you might view forests or fields as habitat for animals. If we want to encourage a diverse and healthy habitat for microorganisms we must provide food, nutrients, proper aeration, pH, water, etc. Organisms live in the microscale environments within and between soil particles.
The Soil Food WebIs very complex
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Presentation Notes
Most people are familiar with the above-ground food web: Plants are eaten by herbivores are eaten by carnivores, and so on. But most plant matter is not eaten by herbivores; it is decomposed by the underground food web. Soil Foodweb is a community of organisms living all or part of their lives in the soil Foodweb diagram shows a series of conversions of energy (arrows) and nutrients as one organism eats another Foodweb fueled by primary producers (Photosynthesisers): plants, lichens, moss, bacteria, algae that use the sun’s energy to fix carbon dioxide Most other soil organisms get their energy and carbon by consuming other organic compounds, organisms and waste by-products All plants (grass, trees, shrubs, agricultural crops) depend on the soil food web for their nutrition. File name: A-3 (145KB). (Also fw.jpg 574K, and fwb.jpg at 422K) Image courtesy of the USDA-NRCS.
20%50%
75%
Plant Succession
Bacterial
Fungal
Nature moves towards a more complex system, more diverse, more productive...Disturbance destroys complexity…Nature starts up again
Dr. David Perry
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Presentation Notes
Early succession bacterial dominated because soils haven’t built to the point to support fungal food soil structure allows bacteria to dominate…supports disease favoring bacteria we’ve created habitat that favors bacteria Weeds *requires high Nitrite levels *Poor soil structure – aeration *Produces large number of seeds
Diversity of Root Architecture and Depths
Don et.al., 2008 Max Planck Inst. Jena
The Soil Food WebDrives Nutrient Cycling
Dr. Nardi
Presenter
Presentation Notes
Most people are familiar with the above-ground food web: Plants are eaten by herbivores are eaten by carnivores, and so on. But most plant matter is not eaten by herbivores; it is decomposed by the underground food web. Soil Foodweb is a community of organisms living all or part of their lives in the soil Foodweb diagram shows a series of conversions of energy (arrows) and nutrients as one organism eats another Foodweb fueled by primary producers (Photosynthesisers): plants, lichens, moss, bacteria, algae that use the sun’s energy to fix carbon dioxide Most other soil organisms get their energy and carbon by consuming other organic compounds, organisms and waste by-products All plants (grass, trees, shrubs, agricultural crops) depend on the soil food web for their nutrition. File name: A-3 (145KB). (Also fw.jpg 574K, and fwb.jpg at 422K) Image courtesy of the USDA-NRCS.
Mineralization and Immobilization
Organisms consume other organisms and excrete inorganic wastes.
Inorganic nutrients are usable by plants, and are mobile in soil.
Organic nutrients are stored in soil
organisms and organic matter.
Organisms take up and retain nutrients as they grow.
Presenter
Presentation Notes
File name: MinImmB.jpg, 51K. (Also: MinImmA.jpg at 100K, and E-2 at 375KB) Image courtesy of USDA-Natural Resources Conservation Service
The Soil Food WebControls Non-Beneficial Organisms
Dr. Nardi
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Presentation Notes
Pest problems are caused by populations that are out of control Predator to prey relationship is unbalanced Many times caused by farming activities that result in habitat that favors one organism over another
Controlling Pest Requires Every Trophic Level
• Must be present
• Must be able to function
IPM
• Prevention
• Avoidance
• Monitoring
• Suppression
Dr. Nardi
Soil Health Planning Principles
• Manage more by Disturbing Soil Less• Use Diversity of Plants to add diversity to Soil
Micro-organisms • Grow Living Roots Throughout the year• Keep the Soil Covered as Much as Possible
Goal: To create the most favorable habitat possible for the soil food web
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Presentation Notes
Following these four planning principles in a systematic approach can accelerate soil health improvements
• Destroy “Habitat” for Soil Organisms• Creates a “Hostile” Environment• Three Types of Disturbance
– Physical (tillage)– Chemical (Fertilizer)– Biological (overgrazing)
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Presentation Notes
Dynamic soil proprieties are those that can be influenced by human activities Include:Soil Organic Matter Structure Infiltration rate nutrient and water holding capacity & availability Soil is Habitat that provides Food, Water & Shelter for organisms to live Agricultural disturbance destroys habitat in which beneficial organisms could thrive and creates habitat that non-beneficial organisms can tolerate or thrive in All three types of disturbance end in degraded soils
What is Tillage?
The physical manipulation of the soil for the purpose of:• Management of previous crop residue• Control of competing vegetation (weeds)
• Incorporation of amendments (fertilizer/manure)
• Preparation of a soil for planting equipment• Recreation for folks who don’t fish or golf
Presenter
Presentation Notes
Tillage had a purpose in past agriculture production, but now we have the technology to plant and harvest nearly any crop without tillage. Now that we know better, we need to do better. Tillage Trivia – 5 U.S. states have images of moldboard plows on their flag (KS, MN, MT, NJ & WI). 14 U.S. states have images of moldboard plows on their state seals (AR, IA, KS, MN, MT, NV, NJ, ND, OK, OR, PA, SD, TN & WI). The U.S. Department of Agriculture has a moldboard plow front and center on its seal.
What Tillage does to the Soil• Destroys aggregates• Exposes organic matter to decomposition• Compacts the soil• Damages soil fungi• Reduces habitat for the Soil Food Web• Disrupts soil pore continuity• Increases salinity at the soil surface• Plants weed seeds
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Presentation Notes
Impacts of Tillage Destroys aggregates– breaks apart macro-aggregates into micro-aggregates Exposes organic matter to decomposition – chops residue into small pieces, stimulates Causes compaction – shearing action of metal on soil compacts soil particles at what ever depth this is being done Damages soil fungi -- destroys habitat for soil fungi to flourish Reduces habitat for all members of Soil Food Web Disrupts soil pore continuity Increases salinity at the soil surface Plants weed seeds
Forest SOM = 4.3 %
CT 17 yr- Soybean monoculture SOM = 1.6 %
20 c
m la
yer
Management Changes Soil Properties & Capacity of Soil to Function
62.8% loss of SOM after
17 yr intensive
tillage
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Presentation Notes
Example of how tillage has changed the dynamic soil properties of this soil, e.g. Soil organic matter, soil structure, infiltration rate, bulk density and water and nutrient holding capacity Key point: Forest soil OM was 4.3% Cropland soil OM now 1.6% 62.8% loss in SOM in 17 years National over 50% of SOM has been lost in past 100 years, most since the 1950’s
Human nature drives us to tillage!
•We enjoy power!•Feel in control!•We can see what we accomplished!
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Presentation Notes
Human’s relate hard physical work with success,
Biological Disturbance
– No crop rotation diversity• Growing single species or few crops in rotation• Lack of diversity limits diversity of plant root
exudates• Hampers the development of a diverse soil biota
– Overgrazing• Plants are exposed to intensive grazing for
extended periods of time, without sufficient recovery periods
Presenter
Presentation Notes
Disturbance to the soil habitat caused by biological means, we don’t think that miss application of biological activities can have an negative impact on soil health and function Monoculture – growing a single species or limited number of crops in a planned rotation Plant exudates attract specific soil microbes, feeding the soil only a limited range of exudates will limit the number of species and different kinds of species in the soil food web Impacts nutrient cycling, building of soil aggregates and soil organic matter, etc. Limits the number of functional groups in the soil, e.g. decomposers, photosynthesizers, bacterial or fungal feeders, results in imbalance, diseases, etc. Overgrazing – exposing plants to intensive grazing for extended periods of time, without sufficient recover periods Next slide goes into detail as to the impacts
Have students identify all of the impacts on the soil that overgrazing leads too, don’t simply focus on the plant
Alternative water sources & controlled access to stream but no control of grazing time on watershed
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Presentation Notes
Lack of understanding on how overgrazing impacts soil health and eventually other resource concerns Here is a grazing system in which the “water quality” resource concern has been addressed Creek has been fenced out 2 alternative water sources have been provided A stream crossing allows livestock to travel back and forth What about the condition of the pasture? Overgrazed Poor forage recovery Weeds creeping in Soil is crusted and sealed over, resulting in poor infiltration and increased runoff
Chemical disturbances: over-application of pesticides, fertilizers, amendments & manures
Presenter
Presentation Notes
Chemical disturbance is the impact on soil health that the over-application of pesticides, fertilizer and manures have.
Impact of Pesticides on Soil Health
• Impacts non-target organisms – not well understood– Fungicide takes out mycorrhizal fungi
• Pesticides simplify, not diversify• May restrict crop rotation • May restrict cover crop diversity
Presenter
Presentation Notes
Pesticides are non discriminating in that the don’t distinguish between the beneficial and non-beneficial organisms They can disrupt an entire trophic level in a soil food web which would impact nutrient cycling and disease control Since they are non-discriminating they simplify the soil biota, reducing the number of species and functional groups that should exist Potential carry over impact on the next crop can limit planting options, leads to a monoculture rotation Same principles applies to the selection of plants in a cover crop mix “Every chemical-based pesticide, fumigant, herbicide and fertilizer tested, harms or outright kills some part of the beneficial life that exists in the soil, (or on the leaf surfaces) even when applied at rates recommended by their manufacturers... Less than half of the existing active ingredients used as pesticides have been tested for their effects on soil organisms.”Dr. Elaine Ingham, 2002, Soil Food Web, Oregon State University
Impact of Fertilizer on Soil Health
• Short-circuits the rhizosphere & P cycle• Depresses activity of natural N fixers• Stimulates bacterial decomposition of SOM• Excess N at risk for leaching or denitrification• Increased soil salinity (Synthetic fertilizers are
salts)
Presenter
Presentation Notes
Short-circuits the rhizosphere The rhizosphere the area adjacent to the root that has the most biological activity taking place, mineralization (nutrient release) and disease prevention being here Excessive fertilizer discourages this area from developing to it full potential Depresses N-fixing bacteria in soil N-fixing bacteria have a mutualistic relationship with legume plants, producing N in exchange for food, when N is available to the plant then they don’t establish or foster these relationship Stimulates bacterial decomposition of Soil Organic Matter Morrow plots in Illinois have shown that addition of N has led to the loss of 50% of the SOM since they began using it in the plot in the 1950 This has been accomplished by stimulating the bacteria through out the soil profile to decompose organic matter N at risk for leaching or denitrification Fertilizer N is applied in one of two forms, NH4+ or nitrate both are inorganic and very water soluble can leach or leave field through surface runoff, field tile etc. Synthetic fertilizers are salts Over application can lead to osmotic shock in plant roots
Impact of Manureon Soil Health
• Can add organic matter and carbon • Build up of P to excessive levels
– Greater than 100 ppm discourages plants from feeding mycorrhizal fungi
• Other issues– Heavy metals– Salts– Pathogens– Soil compaction from application/incorporation
Presenter
Presentation Notes
The addition of animal manure is general good, increase organic matter, provide C source for microbes, etc Excess application of manures leads High P level that discourage plants to develop mycorrhizal fungi relationship, so plant might be getting P from the soil but they miss out on the other benefits that can be obtained, water, other nutrient exchange Manure can contain toxic compounds depending on the food supplements that are being feed. These concentrate in the manure and can build up in the soil
Hard to believe that the same results can be achieved using simpler biological methods!!!
Presenter
Presentation Notes
The challenge to soil health is to convince farmers that they can achieve many of the same results they are seeking when they till by using biological methods Photos are of tillage radish planted in a timely fashion that allows it to growing into the soil profile greater than 12”, notice the soil line The photo in the bottom right shows tillage radishes planted using a split row planter ever 4”. You can see the “bio-drilling that is being achieved, compares to the results that you can get with an inline ripper without the added cost of diesel fuel In addition the tillage radish scavenge excess N, pull up P from deep in the soil profile and provide some nematode control as an added bonus
Healthy Soils are forgiving soils
Presenter
Presentation Notes
Here’s an example system in which the producer has maximized not disturbing the soil. Cover crops is a mix of cereal rye, crimson clover and hairy vetch Using a Brillion cultipacker that he had used previously to knockdown cotton stalks, to roll this 6 foot tall cover down He is spraying as he rolls Lower left picture shows rolling and planting at the same time Lower right picture shows how forgiving health soils, good soil moisture, well aggregated not trouble get seed in the ground and covered.
Soil Health Principle 2
Use Diversity of Plants to add diversityto Soil Organisms
• Plants interact with particular microbes– Trade sugar from roots for nutrients
• Microbes convert plant material to OM• Requires a diversity of plant carbohydrates to
support the variety of microbes • Lack of plant diversity will drive system to
favor some microbes more than others
Presenter
Presentation Notes
Plants exudates attract a particular variety of soil microbes Microbes use these exudates to do the various function that support plant growth, e.g. decompose organic matter, cycle nutrients, enhance soil structure, and control populations of soil organisms including pest The more plant exudates in the soil the wider variety of soil organisms that the soil can support, adds complexity and resilience Lack of diversity reduces the number and types of organism that can thrive, soils are less complex and lack resilience Reference the movie “Supersize Me” The movie is about a man that ate McDonalds food every meal for a month, the lack of diversity in his diet cause his blood work to get out of balance, he gained weight and his general health went down. His doctor’s pleaded with him to get off the diet. This is the same principle as feeding the soil corn exudates every year and the effect it has on the soil organisms
Nitrogen Types in Plant ExudatesNitrate (blue)Amides (Yellow)Ureides (red)
Presenter
Presentation Notes
The percentage of N exported from the roots to the shoots as nitrate (blue), amino acids (green), amides (yellow) and ureides (red). The more diversity in N compounds in the roots the more diversity in the microorganisms that live in and around the roots, because some of these compunds are leaking into the rhizosphere. This graph also shows why a mixture of plants is better than a monoculture in terms of building soil organic matter quality.
Impact of Biodiversity
• Lack severely limits any cropping system
• A diverse and fully functioning system provides nutrients, energy and water
What impact does increasing biodiversity have on a cropping system? Lack of biodiversity limits the copping system, How?? Disrupts how soils function, less nutrient cycling, water infiltration, increase pest (weeds & diseases), etc. A diverse and fully functioning soil ecosystem means that: all the organisms that plants require are present and functioning Nutrients in the soil are in the proper form for plants to take up Nutrients are being held in the soil in non-leachable forms Correct ratio of soil organisms are present Fungi to bacteria Predator to prey When this occurs the system provides the energy, nutrients and water to produce crops Diversity in plant community above ground equals or indicates a diverse soil biota
How to Increasing Diversity in a Crop Rotation
• Lengthen the rotation by adding more crops – Increases soil organic matter– Breaks pest cycles– Improves nutrient utilization and availability– Utilize available water deeper in the soil profile– Provide windows for management
• spread manure• Plant & harvest crops
• Add more plants in the current crop rotation– Utilize cover crops during non-cropping part of the year
Presenter
Presentation Notes
There are 2 basic ways to add plant diversity to a crop rotation Lengthen the current rotation by adding more corps, e.g. corn-bean rotation goes to corn-beans-wheat Benefits include: Increase the amount of biomass produced can increase SOM Planting difference crops breaks pest and weed cycles Planting a variety of shallow and deep rooted crops utilizes soil moisture and nutrients Provides windows of opportunity to spread manure in more suitable time of the year, plant and harvest crops with out conflict, etc. Add more plants in the current rotation Utilize the non-cropping portion of the year to grow cover crops Be sure to use multi-species cover crops when possible
Cover Crop Role in Diversity
1. Allow you to look at cropping periods rather than years
2. Can be used to accelerate rejuvenating soil health
3. Getting 6 to 8 weeks of growth is adequate to get some of the “rotation” effect benefits!
Cover crops and multi-specie cover crops play a big role in adding diversity into a cropping system Farmers are hesitant to add more cash crops to a rotation, cover crops allow for diversity to be inserted into periods of the year that normally would not have a living root growing and no exudates being placed into the soil Success of cover crops has always been judge by the amount of biomass produced above ground, we need to consider the amount of plant exudates that are feeding soil microbes for a period time that normally would not have gotten any food. Having roots grow for a short period of time accomplishes Multi-species cover crops will added to the biological diversity within the soil
Simplified Crop Classification
• Plant morphology – Broad leaf– Grasses
• Plant growth habits– Cool season – Warm season
Presenter
Presentation Notes
How do you know if you have enough diversity in the rotation? Using this simple crop classification system and make sure you have representatives from each functional group in the rotation
What does this ecosystem contain that can be mimicked in cropping systems? Diversity of plant species Diversity of plant function
The Influence of Functional Diversity andComposition on Ecosystem Processes
David Tilman,* Johannes Knops, David Wedin, Peter Reich,Mark Ritchie, Evan Siemann
Presenter
Presentation Notes
Study conducted by Dr. Tillman and others looked at influence of functional diversity and composition on Ecosystem Processes measured in Plant Biomass produced Ecosystem Processes Water cycle Nutrient cycle Biological community Energy Flow species diversity defined: number of plant species added to plots functional diversity defined: number of functional groups added to plots functional composition defined: which functional groups were added to plots Functional Groups classified based on the intrinsic physiological and morphological differences, which influence differences in resource requirements, seasonality of growth, and life history RESULTS: Measured in the amount of biomass produced not by individual ecosystem process A little species diversity can have a big affect on biomass production
The Influence of Functional Diversity andComposition on Ecosystem Processes
David Tilman,* Johannes Knops, David Wedin, Peter Reich,Mark Ritchie, Evan Siemann
Presenter
Presentation Notes
Results Plant composition is important in ecosystem processes Functional diversity has greater impact on ecosystem processes than species diversity The number of functionally different roles represented in an ecosystem is a stronger determinant of ecosystem processes than the number of species Factors that change ecosystem composition will have an impact on the processes, e.g. invasive plants, nitrogen use, soil disturbance, predator decimation The key is that it takes more than a lot of different plant species to impact soil health you need representation from each of the functional groups Results from Tillman study Other studies have shown that the number of species (2, 6,7, 19), the number of functional groups (8), or ecosystem species composition (20, 21) influence various ecosystem processes. Our results show that composition and diversity are significant determinants of ecosystem processes in our grasslands. Given our classification of species into functional groups, functional diversity had greater impact on ecosystem processes than did species diversity. This suggests that the number of functionally different roles represented in an ecosystem may be a stronger determinant of ecosystem processes than the total number of species, per se. However, species diversity and functional diversity are correlated; each was significant by itself, as was species diversity within functional groups; and either species or functional diversity may provide a useful gauge of ecosystem functioning. Our results show a large impact of composition on ecosystem processes. This means that factors that change ecosystem composition, such as invasion by novel organisms, nitrogen deposition, disturbance frequency, fragmentation, predator decimation, species extinctions, and alternative management practices (20, 21), are likely to strongly affect ecosystem processes. Our results demonstrate that all species are not equal. The loss or addition of species with certain functional traits may have a great impact, and others have little impact, on a particular ecosystem process, but different processes are likely to be affected by different species and functional groups.
• 0 5 10 15 20
# of species
Diversity and Microbial Community Biomass
0 5 10 15 20# of species
Diversity and Microbial Community Respiration
Cover Crop Characteristics
Presenter
Presentation Notes
Good resource for infomration related to cover crop Available on line or can be purchased as a book
Mixture of cereal rye, hairy vetch, and field peas as a winter cover crop
Mixture of cereal rye, hairy vetch and crimson clover
Presenter
Presentation Notes
Examples of multi-species cover crops
Soil Health Principle 3
Grow Living Roots Throughout the Year
Benefits:• Increases microbial activity influences the N mineralization
and immobilization• Increases plant nutrient/vitamin uptake/ concentrations with
mychorrhizal and bacteria associations• Increases biodiversity and biomass of soil organisms• Improves physical, chemical and biological properties of soils• Sequesters and redeposit nutrients• Increases OM
Graph is built on data from RUSLE2 run for Greensboro, NC It shows the amount of root mass produced in the top 4” for corn, soybeans and a rye & hairy vetch cover crop Typical corn or soybean will only grow a living root for 100 to 110 days, leaving the soil with no living root growing for the majority of the year Adding a multi-species cover crop growing in the non-cropping part of the year added over 2000 lbs. of root mass providing a food source year round
Cover Crops Retain N in the Soil
J. Luna, OSU, Corvallis
A. H. Heggenstaller, University of Alberta
Presenter
Presentation Notes
A. H. Heggenstaller, University of Alberta Traditional cropping systems only have a living root growing 90 to 120 days of the year Niches exist at both ends of the growing season that provide opportunity for cover crops to used to provide a living root
A. H. Heggenstaller, University of Alberta
Presenter
Presentation Notes
H. Heggenstaller, University of Alberta Cover crops can provide exudates to stimulate soil biology at both ends of the cropping season
How to Keep a Living Root All Year Long
• Lengthen Rotation – Add Wheat
• Select Shorter Season Varieties– Choose 100 -104 day – Only need 6 - 8 weeks to provide benefit
• Interseed into Growing Crops– Planting cover crop before harvesting of cash crop
Presenter
Presentation Notes
There are a variety of ways to get cover crops seeded in order to take advantage of a longer growing season Lengthen rotation, e.g. adding wheat in a C-B rotation Select shorter season varieties, need to have breeders look at higher yielding shorter season varieties Remember having a living root growing for 6 to 8 weeks before a killing frost does provide benefit Figure out ways to interseed cover crops into growing crops
Hairy vetch planted intocorn July 17
Hairy vetch planted intobean June 29
Hairy vetchgood fall growth
Photos 29 Oct 2003
Presenter
Presentation Notes
Photo shows the difference in growing of hairy vetch seeded at to different times of the year Early seeding allowed for more growing, nothing earth shattering here
Fall Biomass Data
• Lose 50% to 80% of fall growth potential with a 1 month planting delay
• Later planting defers growth potential to spring
• Rye is the least impacted by a later planting date
Dry Matter of Both Planting Dates Measured in November
0
1000
2000
3000
4000
5000
6000
7000
8000
Oat
s
Rad
ish+
Oat
s+A
WP
Oat
s+C
rimC
love
r
Oat
s+R
adis
h
Vet
ch+O
ats
Rad
ish
Rye
+Rad
ish
Rye
gras
s
Rye
gras
s+C
rimC
love
r
Whe
at
Rye
gras
s+A
WP
Triti
cale
Vet
ch+R
ye
Rye
Red
Clo
ver
lbs/
acre
Late Aug PlantingLate Sept Planting
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Presentation Notes
Penn State Study conducted in 2011 & 2012 This group of cover crop mixes contained species that would freeze kill Early planting gained 50% to 80% more biomass that late planting
0
1000
2000
3000
4000
5000
6000
7000
8000
Rye
Vet
ch+R
ye
Triti
cale
Rye
+Rad
ish
Whe
at
Rye
gras
s
Rye
gras
s+A
WP
Rye
gras
s+C
rimC
love
r
Vet
ch+O
ats
Red
Clo
ver
Rad
ish+
Oat
s+A
WP
Late Aug plantingLate Sept planting
Dry
Mat
ter (
lbs/
ac)
Cover Crop Biomass in April/May 2010
Spring Biomass DataRye and triticale containing mixtures were least impacted by a later planting date
Ryegrass containing mixtures were moderately impacted by a later planting date
Legumes w/ no spring growing companions were heavily impacted by a later planting date
Presenter
Presentation Notes
Penn State Study conducted in 2011 & 2012 This table contains cover crops that will over winter Late seeding did not affect all cover crop species used, e.g. cereal grains not affected Legume containing mixes were impacted the most
Aerial Seeding
How are farmers getting it done?
Presenter
Presentation Notes
Advantage Seed most anytime Not affected by wet conditions Suited for small seed low rate cover crops Disadvantages Limited on amount of seed they can carry Need to increase rates to compensate for poor seed to soil contact Cost
Penn State Cover Crop InterSeeder & Applicator
Presenter
Presentation Notes
Penn State Cover Crop Interseeder & Applicator With this system, cover crops are interseeded early in the season but provide minimal competition to the corn. The interseeder is designed to be able to apply sidedress N fertilizer and a postemergent herbicide while seeding the cover crop, Eliminates the need for additional trips across the field and reducing the cost of seeding the cover crop.
•Seed cover crops into corn & beans•Uses a Hagie STS 12 with a Gandy Orbit Air seed box. •Covers 90 feet / 36 rows and the hopper holds 65 bu. “
Highboy air seeders
“This is the last and greenest field I did. Still has a little time to go yet, but it should make some corn. Most other fields are brown with grain moisture, I'm guessing, in the low 20's. The ground is
getting more light, so we'll see if that makes a difference.”
Broadcast seeding of cover crop as spray cotton defoliant using a multi-species cover crop mix Great stand Problem was farmer could spray more acres than he could broadcast, hopper not large enough
Corn Chopper --cuts top out of mature corn
Presenter
Presentation Notes
Here’s a radical idea, farmer used a corn copper ( actually the are lawnmower blades) to cut the top off of mature corn (above the ear) while broadcasting cover crop seed. Corn is drying down and waiting to be harvested. The key point to all of the slides being that once you convince farmers of the benefits of seeding their cover crop early they will figure out a way to make it happen.
Soil Health Principle 4
Keep it Covered as Much as PossibleBenefits:• Control Erosion• Protect Soil Aggregates • Suppresses Weeds• Conserves Moisture• Cools the Soil• Provides Habitat for Soil Organisms
Presenter
Presentation Notes
The benefits of keeping the soil covered have focused primarily on the erosion control side, we don’t need to discuss this much, thousands of HEL conservation plans have been written based on this. NRCS has totally missed the mark as providing residue all year round does more than prevent erosion Cooler soils reduce evaporation and conserve moisture Residue provides habitat for soil organisms
Soil Temperatures
• Conserve moisture and reduce temperature. • Crop yields are limited more often by hot and dry,
not cool and wet.
Presenter
Presentation Notes
Notice the temperature difference between bare soil and soil with cover crops. Thermometers are placed 40 feet apart in two differently managed fields Soil temperatures are 20 degrees cooler where cover crop is shading the soil
When soil temperature reaches
140 F Soil bacteria die
130 F 100% moisture is lost throughevaporation and transpiration
113 FSome bacteria species start dying
100 F 15% moisture is used for growth85% moisture lost through
Soil temperatures are a way of determining the health of you cropland and pastures. By placing a temperature gauge on the surface can show you what kind of micro climate you have created Soil temperatures can exceed ambient air temperatures by 10 to 20 degrees Plant use of moisture is directly linked to soil temperature At 70 F soil temps 100% of the moisture is used for growth, none is loss. At 100 F you lose 85% of your moisture through evaporation-transpiration. At 113 F 100% of soil moisture is lost through evaporation-transportation, no plant growth is occurring Plants natural reaction to hot temperatures is to evaporate soil moisture through there system to cool itself. Protein cooks at 120 degrees F. Thus the plant will avoid being cooked by using all the moisture you have caught in the soil for Air Conditioning. At 130 F soil organisms start to die So it is important to manage for cool soil conditions. This is the biggest looser of soil moisture. Hot ground means you have created a drought even during moist years.
What happens to residue?
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Soil organic matter can be broken down into its component parts. One hundred grams (g) or 100 pounds (lbs) of dead plant material yields about 60–80 g (lbs) of carbon dioxide, which is released into the atmosphere. The remaining 20–40 g (lbs) of energy and nutrients is decomposed and turned into 3–8 g (lbs) of microorganisms (the living) 3–8 g (lbs) of non-humic compounds (the dead 10–30 g (lbs) of humus (the very dead matter, resistant to decomposition). The molecular structure of SOM is mainly carbon and oxygen with some hydrogen and nitrogen and small amounts of phosphorus and sulfur. Soil organic matter is a by-product of the carbon and nitrogen cycles.
• Mineralization Rate = 2-3% from Organic N to Inorganic N.
• Resulting in 20 to 30 lbs of useable N per acre.
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This is self explanatory, it shows the potential nutrients available in the SOM that can be tapped as soil health is improved and microbe activities is excellerated
Soil Organic Matter & Available Water Capacity
Percent SOM Sand Silt Loam Silty Clay Loam
1 1.0 1.9 1.4
2 1.4 2.4 1.8
3 1.7 2.9 2.2
4 2.1 3.5 2.6
5 2.5 4.0 3.0
Berman Hudson Journal Soil and Water Conservation 49(2) 189 194 189-March April 1994 –Summarized by: Dr. Mark Liebig, ARS, Mandan, ND Hal Weiser, Soil Scientist, NRCS, Bismarck, ND
Inches of Water/One Foot of Soil1 acre inch = 27,150 gallons of water
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This is AVAILABLE water not simply water being held in the soil profile What does it mean on a practical side The average increase in available water is .5” This amounts to an extra 13,575 gallons of available water Corn water use at it maximum growth rate in the summer uses .25” to .3” of water or 6,000 to 8,000 gallons This amount of extra water would be equivalent to 2 irrigation events to meet corn needs This would amount to decreasing the number of irrigation events needed or extending the time between events It would also mean extra days between rainfall events before non-irrigated crops begin to stress
