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Cover crop research explores supplemental N ahead of soybeans

University of Wisconsin teams are working on ways to help cover crops get established faster and stronger in the fall.

Soybean specialist Shawn Conley tells Brownfield weather in northern states can make establishing a cover crop between harvest and frost challenging. “If you look at the total number of acres, we only have about 8% of all corn and soybean production systems that have these cover crops in their system on an annual basis. A lot of it has to do with timing and being able to get enough growth for it to do what it’s intended to do.”

Conley says research by weed scientist Rodrigo Werle shows the importance of a good cover crop. “You need about forty-five hundred pounds of biomass out there in order to have some weed control, and it’s really hard for us in Wisconsin to really get that, but by adding a little bit of nitrogen to stimulate that early season growth, I think we can get there.”

Conley says the rye grass will take up the nitrogen into the roots and leaves, promoting rapid growth, and then, “We terminate it, and then it slowly releases that back into the soybean crop, which the soybean crop is a huge user of nitrogen.”

Conley says soybeans will easily be able to take up the nitrogen released by the decaying cover crop, since soybean plants don’t usually start fixing their own nitrogen until the V2 or V3 growth stage.

Audio: Shawn Conley discusses cover crops and supplemental nitrogen with Brownfield’s Larry Lee