Cover Crops In the Midwest—Their Potential to Reduce Hypoxia In the Gulf.

Research has clearly shown that cover crops show promise as a management strategy to help reduce nitrate losses in tile drainage in corn and soybean systems in the upper Midwest.  The purpose of this paper is to assess the potential for expanding the use of cover crops in the upper Midwest to help reduce the delivery of nitrate to the Mississippi River and thus, minimize the export of nitrogen to the Gulf of Mexico and reduce the hypoxic zone found there. We focus on five Midwestern states (IA, IL, IN, OH, and MN), which are known to contribute significantly to the nitrate load in the Mississippi River.  First we discuss characteristics that determine the potential effectiveness of cover crops in reducing nitrate losses.  We then assess the relative ease or difficulty of integrating cover crops into different current cropping systems, and include case studies from 10 counties in MRBI (Mississippi River Basin Initiative of the Natural Resources Conservation Service) watersheds as examples.  We briefly discuss that cover crops not only impact water quality and greenhouse gasses, but also perform many other ecological services.  We end the paper with some research and development needs for cover crops.