Environmental Benefits of Cover Crops in Dual Cropping Systems: A Modeling Approach.

Water quality in the Upper Midwest is negatively affected by conventional agricultural practices and the leaching of nutrients, specifically nitrogen nitrate (NO₃-N). Without vegetation on the landscape, exposed soil leads to nutrient loss. An option to reducing NO₃-N leaching is through the implementation of cover crops in a crop rotation. The objective of this study was to assess the potential of field pennycress (Thalspi arvense L.) and winter camelina (Camelina sativa L.) to reduce NO₃-N losses in the leachate when double cropped with soybean [Glycine max (L.) Merr.]. To test this concept, we conducted a 3-year dual cropping field experiment in the temperate/humid Upper Midwest U.S. Soil solution samples were collected using lysimeters at 1 m depth and analyzed for [NO₃-N]. Water drained in each system was simulated using crop models coupled to a Decision Support System. Our preliminary results suggest that NO₃-N losses are less in the winter camelina and the field pennycress with soybean dual cropping than in soybean alone. These findings indicate that improvements may be made to water quality in the Upper Midwest through the integration of cover crops in dual cropping systems. Future steps include assessing our concept on different cropping practices and environments.