Benefits of Cover Crops

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Benefits of Cover Crops Reduce the need for of
f-field OM additions food for micro-organisms
improve soil structure tilth
replenish active OM lost during cultivation
Grow your fertilizer in the field!
Legumes supply much of the need N
in symbiosis with Rhyzobia
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• Rhizobia soil bacteria responsible for
  symbiotic nitrogen fixation on legume roots.
  
• Rhizobia fixes atmospheric nitrogen for use by
  legume plants in exchange for food (sugars) from
  the plant that keep the bacteria living!
  
• Rhizobia are species specific and seed must be
  inoculated the first time it is planted.

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Adapted from P. Sullivan (attra)
Adapted from MCCP
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Cover Crops Crop Rotations Field Timeline Exam
ples
South 40
Back 40
cash crop
cover crop
Jan
Jan
Jan
July
July
Adapted from Building soils for better crops.
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Contributions of Cover Crops to soil organic
matter
Adapted from MCCP
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GM crops improve yields by enhancing soil health
Feed the soil that feeds the crops Soil MO nu
mber and diversity increase rapidly after crop
incorporation During microbial breakdown nutrien
ts are released
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Cumulative benefits of cover cropping
You can increase the range of benefits by 1.
Increasing the diversity of cover crops grown
2. Increasing the frequency of cover cropping
3. Increase the length of time in cover crops
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More Benefits

• Cover crops increase soil active organic matter
  supply and add a quick nutrient boost
  
• Deep rooted rotation crops mine nutrients from
  deeper in the soil profile (P, K, Mg)
  
• Plan ahead nutrient benefits are not
  instantaneous.
  
• SOIL TEST!!!!!!!

Practice diversity and balance!!!
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Compost additions Up to 5 tons per acre annually
without adverse effects Can use 10 tons per acr
e every 2 3 years without adverse effects
SOIL TEST to check for salinity (EC) levels
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Raise maintain soil organic matter

• Requires a sustained effort
• Difficult in sandy soils, easier in clayey soils
• Raise the rate of OM addition above
  decomposition
  
• Reduce the loss through mulching reduced
  tillage
  
• How much OM is enough?
• Sandy soil 2 is very good
• Clayey soil 3 4 is good
• 1 OM 20 tons OM!!!

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Keeping your organic matter with mulches
Objective to cover your soil with mulch to redu
ce moisture loss However, it also reduces temper
ature gains in spring Straw mulch can cause N
availability problems when incorporated
Compost Green manure Crop residues
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• Benefits of Mulching
• - Reduce organic matter breakdown
• - Enhance water availability to crops
• Less extreme changes in temperature
• Can reduce pest infestations
• Reduces soil erosion

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PAPER
WOOD CHIP/BARK
FABRIC
Alfalfa Mulch
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Experiment!
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Questions?
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Useful Links www.sare.org/publications - Managin
g Cover Crops Profitably - Building Soils for Bet
ter Crops www.attra.ncat.org many organic publ
ications Sustainable Soils the place of organi
c matter in sustaining soils and their
productivity. B. Wolf G. Snyder
http//www.soilcrop.colostate.edu/research_exten
sion/extension/organic_soil_presentation.htm
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Thank you!