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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #323470
Title: Converting perennial legumes to organic cropland without tillage

Author
item Anderson, Randal

Submitted to: Renewable Agriculture and Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2016
Publication Date: 5/15/2016
Citation: Anderson, R.L. 2016. Converting perennial legumes to organic cropland without tillage. Renewable Agriculture and Food Systems. 31: 166-171.

Interpretive Summary: Organic producers are interested in no-till systems. A complex rotation combined with no-till disrupts weed population dynamics such that producers may be able to no-till in organic farming. We proposed a 9-year rotation that includes a perennial legume for 3 years. This study showed that red clover (medium type) can be converted to annual crops by a fall mowing strategy in the fall of the third year. Mowing in the fall reduces carbohydrate levels in the crowns, and favor winter kill. The 3-year no-till cycle in red clover reduced weed emergence in corn more than 85% compared with a tilled system. This mowing strategy will enable producers to include red clover in the rotation to suppress weeds and provide biological N for annual crop growth. A no-till system will help organic producers restore and preserve the health of their soils.

Technical Abstract: Organic producers are interested in developing a no-till system for crop production. In this study, we examined management tactics to convert perennial legumes to annual crops without tillage. Our hypothesis was that reducing carbohydrate production in the fall by mowing would favor winterkill. Mowing treatments were imposed in the fall of the third year of alfalfa or red clover, and corn planted in year 4. The conventional practice of tillage to convert legumes to cropland was also included as a treatment. Mowing in autumn reduced red clover biomass 93% compared to alfalfa when measured 3 weeks after corn planting. Red clover biomass was still 75% less than alfalfa 6 weeks after corn planting. Fall mowing suppressed red clover sufficiently to enable corn seedlings to establish, but corn seedlings did not survive in mowed alfalfa due to alfalfa competition. Corn grain yield following red clover was similar in the mowed and tilled treatments when weeds were present. Late season clover and weed growth reduced corn yields 46% compared to weed-free corn. Weed emergence in corn was three times higher after tillage compared with the mowed treatment. Converting red clover to annual crops with fall mowing will support a no-till system for organic farming.