Best management practices to integrate cover crops and manure
Lead Researcher: Melissa Wilson, Assistant Professor at the University of Minnesota’s Department of Soil, Water and Climate
Wilson’s research focuses on pairing up cover crops and manure application to see if the tandem can work together to hold onto nutrients longer and improve soil health.
She is looking at the best timing of planting the cover crop, how the timing of liquid manure application impacts the system and whether to use oats or winter rye—two of the most popular choices for cover crops in Minnesota. She is also studying if using cover crops gives farmers more flexibility on manure application, which is typically applied in the fall during a tight window.
The research is comprehensive, both geographically and agronomically, to ensure that it will be useful to farmers across Minnesota—whoever has access to manure and wants to incorporate cover crops. Wilson has developed the project at locations in Morris, Nicollet, Waseca and Trimont, consisting of two scientific plots and two on-farm plots. Across these locations, Wilson is testing four different treatments: manure and cover crops, cover crops only, manure only, and conventionally cultivated ground with neither manure nor cover crops added.
She is also testing different rotations: soybeans into corn, continuous corn silage, and sweet corn into corn. With soybeans, she is testing planting the cover crop seed just before leaf drop, to see if the layer of shed leaves creates a beneficial environment for germination. With the silage experiment, Wilson is trying interseeding—planting the cover crop when the corn is still small, at V4 to V5 (pictured), to give it another several weeks of growing degree days.
To assess improvements in soil health they will examine increases in the bulk density of the top several inches of soil, increases in microbial biomass, and other factors.