Winterkilled Cover Crops Interseeded Late Into Corn and Soybean Within Different Tillage Practices In the Upper Midwest, U.S.A

Abstract

The successful integration of cover crops in the conventional corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] agroecosystem in the U.S. upper Midwest is challenging due to poor establishment, extensive use of fall tillage, and a short planting season. Most research conducted in the region has assessed the benefits of overwintering cover crops, but no research has assessed the benefits of winterkilled cover crops seeded late in the growing season in the U.S. upper Midwest. Also, questions remain about the synchrony of N release from their residue decomposition and uptake by the next major crop during the growing season. Winterkilled cover crops are an attractive option to growers if they can provide ecosystem services similar to overwintering annual cover crops. The goal of this thesis is to assess the potential of biomass production of winterkilled cover crops as affected by major crops and tillage practices, determine cover crop effects on corn and soybean production, and advance our understanding of the fate of N as affected by late interseeded winterkilled cover crops in corn and soybean rotation within different tillage practices.