Interseeding Cover Crops into Corn and Soybeans: What We’ve Learned
Sustainable Agriculture
Jennifer Brhel
Extension Educator
Nebraska Extension
York
Abstract
More farmers are seeking alternative ways to reduce inputs such as nitrogen and herbicides. One option in doing so includes interseeding cover crops between crop rows. Goals for this include the potential to reduce chemical and nitrogen inputs, reduce soil erosion, increase diversity, and provide fall forage. From 2020-2022, cover crops were drill interseeded into V3-V4 corn over 12 site-years and into emergence or V2 soybean for 2 site-years. This was the result of a partnership between The Nature Conservancy, Upper Big Blue Natural Resources District, Nebraska Extension, Kelloggs, and farmer cooperators. July 9, 2020 and 2021 windstorms and June 14, 2022 hailstorms impacted these locations. Cover crop biomass was measured prior to harvest in late September each year. Ten of the twelve site-years had greater cover crop biomass in the interseeded treatments than weeds in the check treatment with average cover crop biomass ranging from 277 lb/ac to 4541 lb/ac. Six of the twelve site-years showed a yield loss in corn of one to ten bu/ac while none of the soybean locations showed a yield loss in the interseeding treatment. Ten of the twelve corn and one of the two soybean site-years showed reduced profitability with interseeding compared to the check. Soil health samples (Haney and PLFA) showed increased soil health across all locations from 2020 to 2022 for both the check and interseeding treatments. Reasons for this will be explained in addition to other observations, what was learned, and future directions. Results of this study have been shared via Extension news articles and websites, soil health and regenerative ag conferences, TV interviews and an interseeding driving tour where attendees could join in at any of six locations in four counties on June 29, 2021.
Authors: Jennifer Rees, Steve Melvin
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Jennifer Rees Extension Educator, Nebraska Extension, Nebraska, 68467
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Steve Melvin Extension Educator, Nebraska Extension, Nebraska, 68826