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Interseeding Winter Rye with Soybeans for Weed Suppression

Organic soybean producers in the Midwest have developed weed management programs that rely on tillage-intensive measures that include stale seedbedding, tine weeding, rotary hoeing, and inter-row cultivating. While these measures are often effective, there is much interest in decreasing soil disturbance and tillage in order to conserve soil structure and organic matter, and to obtain good weed suppression in-row. Moreover, interest is growing in exploiting ecological interactions between intercrops (two or more crops grown in the same field) to suppress weeds and obtain more living cover across the organic farm landscape.

To address these interests, MFAI agroecologist Dr. Nicole Tautges and Executive Director Perry Brown are beginning a collaboration with organic crop researchers Dr. Erin Silva and Lea Vereecke (Organic and Sustainable Agriculture Research and Extension program, UW-Madison; http://www.uworganic.wisc.edu/) to investigate soybean + winter rye interseeded systems, for organic soybean production. Winter rye will be seeded alongside soybeans on the same planting date, and will germinate and grow quickly next to the slower-growing soybeans, suppressing weeds while the soybeans develop. As the summer heat progresses, the winter rye will slow growth and die back, allowing the soybeans to grow up and develop a canopy, reaching the point where they can suppress weeds themselves. Dr. Silva and Vereecke have been working on this trial for several years with promising results in terms of weed pressure and soybean yields, and are conducting trials this year to refine soybean establishment and answer questions regarding soybean row spacing and planting date. MFAI researchers are comparing three planting dates of soybean+rye and two row spacings, 7.5″ and 30″, compared to a control treatment of 30″ row soybean with no rye interseeded, relying on traditional interrow cultivation techniques. Throughout the summer, they will evaluate weed pressure and biomass production of rye and soybeans, as well as the most important outcome, soybean grain yields, in the fall. Results will be compared with the same trial being conducted by UW-Madison researchers at a site in Arlington, WI, to compare yields and trends, to nail down the most effective soybean and rye establishment practices to minimize weed suppression and maximize organic soybean yields.

Stay tuned for updates on trial outcomes this summer, as well as photos, videos, and virtual field days showcasing this trial and demonstration of using intercropping for weed control in organic grain production systems. Check out more work of Dr. Silva and Lea Vereecke here: http://www.uworganic.wisc.edu/ and Dr. Silva’s Organic Grain Resource and Information Network, (OGRAIN), here:  http://www.uworganic.wisc.edu/ograin/.