1. Managing Organic Matter for Soil Health & Fertility
Resilient Farmer Workshop April 28, 2012 Kerr Center for
Sustainable Agriculture Steve Diver, M.Sc. Agri-Horticultural
Consulting www.agri-synergy.com Kerr Center for Sustainable
Agriculture Poteau, OK
2. Without living organisms and organic matter, the birth of
soil is not possible Kyoichi Kumada (1987) Objectives for this
Workshop 1. What is soil organic matter (SOM) 2. Why is SOM
important2. Why is SOM important 3. Vital role of soil biology 4.
Contribution of SOM to soil quality and fertilty 5. Managing SOM
and soil foodweb habitat
5. Soil Organic Matter Organic matter is 1-6% living biomass
10-20% humus of total soil mass active fraction 10-20% humus 60-80%
The living, the dead, and the very dead Vermont Agric Exp Sta
Bullletin 135, 1908
6. Soil organic matter encomposses all organic components of
the soil: Living organisms Fresh residues Image: soils.usda.gov
Fresh residues Decomposing OM Stabile OM
7. Soil organic matter Living organisms (plant roots, fungi,
bacteria, worms) Fresh residues (crop residues, sloughed roots,
dead insects, animal manures, microbial secretions) Decomposing
(decaying leaves & stalks; partly recognizable & partially
stabilized OM) Stabilized OM (transformed, recalcitrant OM or
humus) Brady and Weil, 1996SOM dynamic = changing =
transforming
8. What is Humus? Humus is the end result of organic matter
decomposition (break-down) and transformation (build-up) into a
complex, dark-brown, amorphous-heterogenous (non- crystalline,
non-uniform) structure that no longercrystalline, non-uniform)
structure that no longer resembles the decaying matter of origin,
is resistant to further microbial decay, and . has chemical and
physical properties of great importance to soils and plants.
9. Humus properties: 1. Humus particles become bonded to
clay-silicate surfaces, leading to the formation of clay-humus
complexes. 2. Humus stores and releases soil N. 3. Humus possesses
buffering capacity3. Humus possesses buffering capacity 4. Humus
possesses cation exchange capacity 5. Humus possesses anion
exchange capacity 6. Humus adsorbs pesticides and other
agricultural chemicals. Soil Fertility Management for Sustainable
Agriculture James F. Power and Rajendra Prasad, CRC Press,
1997
10. % Organic Matter (dry weight) via Lab Test Image: Rodale
Institute 5%OM 1%OM
11. SOM Colorimetric Field Test Using Sodium Hydroxide/EDTA
K-State Soil Test Kit www.ksre.ksu.edu
12. Active Organic Matter Test Permanganate Oxidizable C Image:
www.certifiedcropadviser.org
13. Soil quality is the capacity of a soil to function (in a
farm or ecosystem) and thereby sustain productivity, maintain
environmental quality, and promote plant and animal health Physical
Chemical NPK Ca Mn Mg S Fe BiologicalSoil Health Aim is to manage
for balance between all three soil components
14. Learn about Soil Quality Indicators & How they are
Measured
15. Soil Organic Matter (SOM) influences all three soil
components & improves soil health Physical Chemical Biological
Soil Organic Matter Soil Health
16. Function of Soil Organic Matter and the Effect on Soil
Properties, CSIRO 2004
17. The Vital Role of Soil Biology Physical Chemical
BiologicalBiological Soil microbial biomass is the eye of the
needle through which all organic material that enters the soil must
pass Jenkinson, D.S. 1977. The soil biomass. New Zealand Soil
Science News, 25: 212-218.
18. Foodweb pyramid in one square meter of soil James B. Nardi,
Life in the Soil, 2007
19. SoilSoil MicrofloraMicroflora Fungi BacteriaBacteria
Actinomycetes Fungi FungiFungi FungiFungi after Balser, Univ of
Wisconsin AlgaeAlgae
20. SoilSoil MicrofaunaMicrofauna -- MesofaunaMesofauna Mite
Nematode Protozoa after Balser, Univ of Wisconsin Springtail
22. Soil microorganisms live in association with plant roots
and excrete nutrients & sticky substances VAM mycorrhizal fungi
on plant root: Paula Flynn Alfalfa root with bacterial rhizosphere:
Jennifer Fox
24. Whats up with Soil Structure? Physical Chemical
BiologicalBiological Soil structure is a key factor in the
functioning of soil, its ability to support plant and animal life,
and moderate environmental quality with particular emphasis on soil
carbon sequestration and water quality. -- Ratan Lal, Ohio State
University, 2005
27. Photo: Joo Carlos de Moraes S Universidade Estadual de
Ponta Grossa, Brazil Roots, fungal hyphae, & microbial glues
stabilize soil macroaggregates and promote good soil structure
28. Colony of bacteria on a humus aggregate EPS
ExopolysaccharidesEPS Exopolysaccharides Image: University of
Bremen (Germany)|www.microped.uni-bremen.de
29. Fungal hyphae attaches to clay particle via polysaccharide
glue Image: University of Bremen
(Germany)|www.microped.uni-bremen.de
30. Fungal myceilum stabilizing micro-aggregate Image:
University of Bremen (Germany)|www.microped.uni-bremen.de
31. Actinomycete filaments stabilizing soil structure Image:
University of Bremen (Germany)|www.microped.uni-bremen.de
32. 25 yrs of CT corn25 yrs of CT corn 20 yrs bluegrass, then 5
yrs CT corn 20 yrs bluegrass, then 5 yrs CT corn Water stable
aggregate test on rotation plots Photo: Ray Weil, Univ of
Maryland
33. Dispersed Water Stable Aggregates 1.0% C 1.4% C Adding
Water to Soil Samples 25 yrs of25 yrs of conventionalconventional
corncorn 25 yrs of25 yrs of conventionalconventional corncorn 20
yrs of bluegrass, then 5 yrs conventional corn 20 yrs of bluegrass,
then 5 yrs conventional corn Photo: Ray Weil, Univ of Maryland
35. The Role of OM in Soil Fertility Physical Chemical
BiologicalBiological Cation exchange capacity Anion exchange
capacity Nitrogen mineralization Slow-release fertility Source of
N, P, K, S, micronutrients
36. Nitrogen Released from Organic Matter In surface 7-inch
depth of soil (2,000,000 lbs) % OM Stable OM lbs/ac Total N lbs/ac
Lbs N/ac Released in Silt Loam Soil 1.0 20,000 1,000 15-30 1.5
30,000 1,500 22-45 2.0 40,000 2,000 30-60 2.5 50,000 2,500 37-75
3.0 60,000 3,000 45-90 3.5 70,000 3,500 52-100 4.0 80,000 4,000
60-120 4.5 90,000 4,500 67-135 5.0 100,000 5,000 75-150 Soil
Fertility and Corn Production, Univ of Missouri Agr Exp Sta Bull
583 (1952)
37. Negatively-charged clay platelets attract
positively-charged cations; adsorption Colloidal = glue-like
Managing Healthy Sports Fields, Paul D. Sachs, 2004
38. Clay-Humus, Seat of Soil Fertility Clay-humus architecture
with: Massive surface area Negatively-charged exchange sites
Organo-mineral complex Siegfried Luebke, CMC Compost Group
39. Managing Organic Matter and Soil Foodweb Habitat Keep the
Soil Covered (year-round) Living crops, crop residues, living cover
crops, killed cover crop mulches, organic mulcheskilled cover crop
mulches, organic mulches Feed the Soil (supply carbon & mineral
foods) Green manures, cover crop roots, composts, carbon pulses
(liquid fish, molasses), minerals (P, K, Ca, Mg, S)
40. Managing Organic Matter and Soil Foodweb Habitat Reduced
Tillage & Common Sense Tillage Minimum-till, no-till, surface
cultivation Tillage with Humus Management = OK Tillage neglecting
Humus Management = Avoid Bio-Complexity Above & Below Ground
Cover crop mix, crop diversity, intercropping
41. Five Things to Know About Cover Crops 1. Multiple Functions
& Uses in Cropping System 2. Plant Species Choices &
Mixtures 3. Promote Growth of Cover Crop Biomass 4. Surface Mulch
& Green Manuring Options4. Surface Mulch & Green Manuring
Options 5. Promote Break-Down (organic matter digestion) &
Build-Up (humification)
42. Keep the Soil Covered Baled mulch from cereal cover crop
Potomoc Vegetable Farm, Virginia
43. No-Till Soybeans in Brazil Photo: Joo Carlos de Moraes S
Universidade Estadual de Ponta Grossa, Brazil
44. A Guide to Green Manure, Cover Crops and Cultivated Legumes
by Ralph Waldo Earthworm
45. Cover Crops for Every Season Buckwheat Crimson Clover
Cool-season Warm-season
46. Image: Joel Gruver, NCSU-CEFS Rapeseed Crimson clover Rye
Wow ! Look at that root !
47. Air above each acre of earth contains 36,000 tons (72M lbs)
of Nitrogen Rhizobium nodules on legume N fixationRhizobium nodules
on legume = N fixation
48. Bio-Complexity = Above & Below Ground
49. Peregrin Farm, NC Movable Hoop House with Cover Crops
50. Roller-Crimper, USDA-ARS in Alabama Widely practice in
South America using Black Oats cover crop
51. Organic No-TillOrganic No-Till Corn with Roll-Plant System
Image: Jeff Moyer, Rodale Institute
52. Mechanical-Killed Cover Crop Mulch Image: Jeff Moyer,
Rodale Institute
53. Sicklebar Mower Mechanical-Killed Cover Crops Image: George
Kuepper, Kerr Center for Sustainable Agriculture
54. Photo: Ray Weil, Univ of Maryland Whats the difference
between these two farms? Mid-Atlantic Drought, 1996-97
55. Conservation tillage Photo: Ray Weil, Univ of Maryland
Keeping the Soil Covered Conventional tillage Mid-Atlantic Drought,
1996-97
56. The First Book of Farming (1905) by Charles L.
Goodrich
57. Green Manuring Spading Machine = SOM incorporation Potomoc
Vegetable Farm, Virginia
59. Humus management practice: bio-inoculating green manures
& crop residues Pfeiffer Field & Garden Spray, Josephine
Porter Institute, over 50 species of SOM digesting and humifying
microbes Gerald Wiebe, Manitoba (Canada), compost extract with
microbial food additives to enhance microbial digestion of crop
residue incorporation
60. Compost is a Managed Process of Organic Matter
Decomposition & Humification C:N ratio Particle size Mixing
Porosity Temperature Moisture Aeration Microbes Transforming raw
organic matter into humus
61. Transformation of raw organic matter into stabilized
compost occurs in a succession of temperature & biological
processes Phases of Compost Heating, Cooling, and Maturation FiBL /
IFOAM Training Manual on Organic Agriculture in the Tropics
62. Compost Rate of Application High 10-15 tons per acre (20-30
cu yds) RegularRegular 5 tons per acre (10 cu yds) Low 2-3 tons per
acre (4-6 cu yds)
63. Dairy Manure Compost (Texas)
64. SEM MicroscopicSEM Microscopic View ofView of
CompostCompost ParticleParticle Miloslav Kalb, Guelph Food Research
Centre
66. Five Principles of Agriculture for the Humid Tropics by
Roland Bunch 1. Maximize organic matter production 2. Keep the soil
covered 3. Use zero tillage3. Use zero tillage 4. Maximize
bio-diversity 5. Feed the crops largely through the mulch GM/CC
Mulches + Zone-Till + Agroforestry Nutrient Access (Ana Primavesi)
vs Nutrient Quantity Concept
67. USDA Natural Resources Conservation Service Goals for SOM
Management 1. Till the soil as little as possible1. Till the soil
as little as possible 2. Grow as many different species of plants
as possible through rotations & diverse mixtures of cover crops
3. Keep living plants in the soil as long as possible with crops
& cover crops 4. Keep the soil surface covered with residue
year round
68. Presented at the Kerr Center for Sustainable Agriculture, a
non-profit organization in southeast Oklahoma, as part of a
USDA-NRCS Conservation Innovation Grant. Steve Diver, M.Sc.
Agri-Horticultural Consulting www.agri-synergy.com
[email protected]
