COVER CROPS REDUCE WATER RUNOFF ORINCREASE WATER INFILTRATION
SOIL PHYSICAL PROPERTIES FOLLOWING 3YEARS OF COVER CROPS Treatment Water-Aggregate Stability Pentrometer Bulk % Increase over control % increase Mg/m3 Corn/Soybean 1.32 Corn/rye/soybean/rye 9 19 1.24 Corn/rye/soybean/hairy vetch 13 8 1.23 Corn/rye/soybean/Hv+rye 17 16 1.23 From Villamil, et al 2006
CAN COVER CROPS AND NO-TILLDECREASE GREENHOUSE GASES?
The Culprits: Greenhouse Gases United StatesGreenhouse Gas Emissions, 2010 Carbon Dioxide (C02) is the most prevalent greenhouse gas. But other gases have a greater potential to warm the climate. • Methane (CH4): 20 x more effective at warming the atmosphere than CO2. Image created by EPA • Nitrous oxide (N2O): 300 x more effective.
CO2 EMISSIONS AND CARBON STORAGE Agriculture 25% of CO2 Sources Tillage, N Production, Cover Crops Decrease CO2 Release from Increased C Storage However, With Tillage Much of the Benefit is Lost Cover Crops with Tillage Less C Storage than No-Tillage without Cover Crops
GREENHOUSE GASES IN AGRICULTUREU.S. Nitrous Oxide Emissions Agriculture is the main source of nitrous oxide in the U.S., due in large part to nitrogen-based fertilizers, but residue breakdown also contributes Image created by EPA
NITROUS OXIDE-N20 CONTRIBUTED BYAGRICULTURE Anerobic Conditions wet Nitrogen Fertilization 1.5% of all N is lost as N20 Animal Manures/Compost N from Cover Crops?
THIS IS WHAT HAPPENEDIN 2008, 2009, 2010, 2011
Bradford Research Center, 5 miles east of Columbia, MO (Boone County) Organic Farmer Cooperators: David Gray, Montgomery County, MO Warren Wilson, Audrain County, MO Terry Littrell, Audrain County, MO James Maberry, Livingston County, MO
USDA-NIFA OREI Grant Greenhouse gas emissions from organic production using tillage with and without cover crop and no-till with cover crop How to plant corn into a cover crop (timing and way of destroying cover crop) Summer cover crops to follow wheat CERES TRUST Grant Transition strategies for going from conventional to organic grain crop production Organic Vegetable Production and Soil Health
Treatments of the study are: 4 Compost rates in subplots, based on crop P needs Plots are: No-till with cover crop, Tilled with cover crop, Tilled without cover crop Photos taken June 22, 2012, DOP May 21
COMPOST APPLICATON BASED UPON P Compost:3-2-2 Wheat P Recommendation-80 lb P205/acre Corn P Recommendation- 120 lb P205/acre Soybean P Recomendaton-90 lb P205/acre Wheat P Treatments: 0, 40, 80, and 120 lb P205/acre Wheat Compost Application Rates: 0, 1333, 2666, and 4000 lb Compost/acre
2012 Wheat Yield 60 50Bushels/acre 40 30 20 10 0 0 lbs/acre 2105 lbs/acre 4210 lbs/acre 6315 lbs/acre Compost Rate 2105 lbs compost contains 40 lbs P and 59 lbs N 4210 lbs compost contains 80 lbs P and 117 lbs N 6315 lbs compost contains 120 lbs P and 176
Soil moisture in cover crop and no cover crop plantson May 16, 2012 (one day before corn planted, 15days after last rain) Treatment Depth (inches) Soil Moisture (%) Rye cover crop 0 to 2 17 2 to 6 19 6 to 10 19 No cover crop 0 to 2 12 2 to 6 16 6 to 10 25 Field capacity is approximately 34% and the wilting point is approximately 18 % soil moisture. Conclusion- cover crops conserved moisture in seed zone but depleted deeper soil moisture.
ORGANIC PRODUCTION-COLLECTING CO2 ANDN2O SAMPLES
SOIL MOISTURE RETENTION BY COVER CROPS IN CORN DAR= days after rain (irrigation)
SOIL MOISTURE RETENTION BY COVER CROPS INSOYBEAN DAR= days after rain (irrigation)
SOYBEANS ON JULY 16… All look about the sameTill, no cover crop Till, with cover crop No-till, with cover crop Weed control 1 cultivation in tilled soybeans and corn, 2 minor hoeings in all plots. Weeds are being held back well by This alley area has had no cover crop and drought. weed control other than rolled cover crop
CORN NOT THE SAME STORYJUNE 22, 2012No-till with cover Tilled, no Tilled, withcrop cover crop cover crop
JULY 16, 2012 Tilled, no cover crop Tilled, with cover crop
2012 Soybean Yield 50 45 40 35Bushels/acre 30 25 20 15 10 5 0 no-till tilled + cc tilled no cc Tillage Type
PLANTING CORN INTO A COVER CROP(RYE+HAIRY VETCH) IN A NO-TILL FIELD How should cover crop be destroyed? Rolling or Chopping When should corn be planted? Before or after cover crop destruction Planted into standing cover crop Destroyed and planted same day Planted 1 week after destruction Planted 2 weeks after destruction
DAY OF DESICCATION 5 DAYS LATER Flailed Rolled Rolled FlailedTO ROLL OR FLAIL CHOP
PLANT PERPENDICULAR TO THE WAY IT SEED TO SOIL CONTACT CAN BE AWAS ROLLED CHALLENGEWHAT IF THE COVER CROP IS STILL ALIVE?
Corn germination when planted into rye cover crop 100 90 80Plant count per 10 feet 70 60 50 40 30 20 10 0 chop roll chop roll chop roll chop roll before cc destroyed same day cc 1 week after cc 2 weeks after cc destroyed destroyed destroyed
SUMMER COVER CROPS TO FOLLOW WHEAT Why let your field build up its weed bank like these plots with no cover crop planted?
Get weed reduction and improved soil organicmatter with summer cover crops likebuckwheat and sorghum-sudangrass. Theseplots had no herbicide and are all no-till
Follow wheat with a legume summer cover crop, such ascowpea, which will fix nitrogen. If followed up with awinter cover crop, that nitrogen will continue to beavailable for your crop the following summer. Cowpea Weedy plot with no cover crop
Sorghum sudangrass is very effective at controllingweeds and contains chemicals that can persist in the soiland continue to control weeds in the following season.Best to follow with soybeans. Sorghum Weedy plot with sudangrass no cover crop
Sunn hemp and sesbania are two other nitrogen fixing summercover crops. Seed costs are a little higher than for othersummer cover crops. If government programs continue toencourage cover crop usage, the market for cover crop seed willincrease and prices may lower. Local production of cover cropseed should also be considered. Sunn hemp sesbania
Summer Cover Crop Yields 25000 20000Pounds/acre of dry matter produced 15000 10000 5000 0 Crop Species
Percentage of weed cover100%90%80%70%60%50%40%30%20%10% 0% buckwheat cowpeas fallow sesbania ss sunn hemp turnip winter radish
CERES FOUNDATION Transitioning to Organic Weed Control number one problem Soil Quality Build up Strategies
STRATEGIES FOR TRANSITIONING Cash Crop All Three Years? Weed Control Strategies Tillage vs No-Tillage
TREATMENTS Always use a polyculture cover crop- legumes, grasses, and brassicas Treatment 1: always use a crop that is mowed or incorporated into the soil-no cash crop-includes sorghum x sudangrass (SXS)
TREATMENTS Treatment 2-cover Treatments 5 and 6- crops first year (SXS): same as treatments 3 cash crops 2nd (grain and 4 except tilled sorghum) and 3rd years. Treatment 7: tilled sorghum x sudan first Treatments 3 and 4: year followed by no-till-soybean/grain wheat/soybean/corn sorghum or soybean/corn rotation
WHY SORGHUM? Allelopathic Chemicals released from roots that inhibit weed germination No GMO’s Sorghum Bicolor is also shattercane!