The Impact of Cover Crops, Tillage, and Crop Rotation on Yield in Midwest Grain Systems.

Cover crop adoption in the Midwest is likely limited due to a lack of understanding of how cover crop selection impacts corn and soybean yield. Management factors such as reduced tillage and crop rotation potentially complicate cover crops impact on yield. Treatments considered in this study were crop rotation: Corn/Soybean, Soybean/Corn, and Continuous Corn; cover crop species: hairy vetch (Vicia villosa Roth) and cereal rye (Secale cereal); tillage: No-till and reduced tillage. The objectives of this study were: (1) determine the degree by which cover crops, tillage, and crop rotation impact corn and soybean yield, (2) Investigate the interaction between cover crop selection, tillage, and crop rotation, (3) Identify the combination of cover crop selection, tillage, and rotation that optimizes yield and profitability. These experiments took place at the Purdue Agriculture Center for Research and Education (West Lafayette, IN). No significant differences were observed in soybean treatments. However, across cover crop treatments continuous corn resulted in an 8% reduction in grain yield compared to corn following soybeans. Additionally, in corn, cereal rye (13.43 Mg ha^-1) and Mixture (13.31 Mg ha^-1) treatments had significantly less yield relative to the Control (14.18 Mg ha^-1) and Hairy Vetch (14.07 Mg ha^-1) treatments. No significant impact of tillage on corn or soybean yields was observed. This data demonstrates the potential for cover crop treatments, dominated by cereal rye, to result in corn yield losses. This study will be extended into the 2017 and 2018 field seasons. Additional measurements of corn N uptake at key growth stages will be added to help better understand the impact of cereal rye on corn growth and yield. Improved understanding of how cover crops, tillage, and crop rotation influence corn and soybean yields in the Midwest will potentially lead to increased cover crop adoption.