Why are cover crops essential on organic farms?

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2 Workshop outline Why are cover crops essential for organic farms? How cover crops can help you meet specific management goals Integrating cover crops into your system Questions

3 Why are cover crops essential on organic farms? Protect the soil from erosion and runoff. Supply the soil with organic matter, which: Improves and maintains good soil structure Enhances the activity and diversity of soil organisms Provides nutrients for crop growth. If legumes, provide nitrogen to subsequent crops through biological nitrogen fixation.

4 Why are cover crops essential on organic farms? Scavenge nutrients in the soil, making them available for subsequent food crops Suppress weeds Fight diseases and pests because they can: Serve as "break crops" (nonhost crops) Act as refugia for beneficial insects and other organisms Alter the soil environment to make it unfavorable to soilborne diseases

5 Management Goal: Improving/Sustaining Soil Quality From the National Organic Rule: Soil quality is a term that serves as a central performance standard for the use of any method or substance in an organic farming system, in that such use may not result in measurable degradation of soil or water quality. In order to determine whether a given operation is in compliance with the regulations, farmers and certifiers must have a clear understanding of what soil quality is and how it may be measured.

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11 Nitrogen fixation In to using purchased inputs, fixation should average lb/year as 3-5 year average. Red clover Hairy vetch Crotolaria winter peas

12 Legume cover crop Inoculum Low soil nitrate

13 Other ways cover crops increase/ maintain soil quality Food for soil organisms Active carbon Not eaten immediately Feeds good fungi, worms etc. Used up faster with cultivation, fertilizer

14 Other ways cover crops increase/ maintain soil quality N- fixa)on with legume cover crops Peas Vetches red, berseem, crimson clovers Yellow sweetclover, alfalfa

15 Crimson Clover

16 Management Goal: Weed suppression Fast-growing cover crops can suppress this season s weeds Reduce emergence Reduce growth Reduce/prevent seed set Buckwheat can suppress perennial weeds, e.g., Canada thistle, quackgrass Overwintering cover crops (e.g., rye, rye/vetch) can suppress spring emerging weeds. BUT: Short-duration cover crops don t reduce the current weed seedbank

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19 Buckwheat suppressing thistle

20 Two summer legume cover crops: Crotolaria (rear) is suppressing quackgrass and annual weeds; cowpea (foreground), not so much

21 Integrating Cover Crops into your Niches in )me System ABer early crop in midseason ABer harvest as a winterkilling or overwintering cover crop As an early spring or spring cover

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30 Grasses Late summer/fall cover crop op)ons Japanese millet, oats, rye Legumes Red clover, berseem clover, yellow sweetclover Peas Hairy vetch Mustards Mixtures

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32 Spring cover crop op)ons Oats, oat/pea mix (early) Mustard Red clover Vetch White clover Yellow sweetclover Berseem clover Crimson Clover Annual ryegrass

33 Integrating Cover Crops into your System Niches in space Between rows Between hills

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35 Good resources Managing Cover Crops Profitably, Sustainable Agriculture Network. Available from sare.org Northeast Cover Crop Handbook, Marianne Sarrantonio (Rodale). Available through seed companies. Crop Rotation on Organic Farms by Chuck Mohler & Sue Ellen Johnson. Available from NRAES.org Cornell Soil Health Assessment Manual by Beth Gugino et al. soilhealth.cals.cornell.edu Cover crop selection tool By Thomas Björkman covercrop.net

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37 Good resources Crop Rotation on Organic Farms by Chuck Mohler & Sue Ellen Johnson. Available from NRAES.org Cornell Soil Health Assessment Manual by Beth Gugino et al. soilhealth.cals.cornell.edu Cover crop selection tool By Thomas Björkman covercrop.net

38 Good resources Northeast Cover Crop Handbook Marianne Sarrantonio Rodale Press; avail at Johnnys Building Soils for Better Crops Fred Magdoff and Harold van Es SARE