Simulated Impacts of Winter Rye Cover Crop on Continuous Corn Yield and Soil Parameters

Cover crops (CC) provide numerous ecosystem services such as improving soil health, reducing nutrient loss, increasing productivity, and mitigating greenhouse gas emission. However, adoption of CC has been hindered by perceived negative impacts on main crop productivity and additional production costs. This is partly attributed to the gap in current state of knowledge in CC and its interaction with main crop production under different biophysical conditions. In this study, Decision Support System for Agrotechnology Transfer model was used to evaluate the long-term impact of cereal rye (Secale cereale L.) on corn (Zea mays L.) yield, soil organic carbon (SOC), nitrate leaching, soil water, and drainage for a range of climate, soil, and irrigation management in Eastern and Central Nebraska. A 30-year (1991-2020) simulation showed no difference in corn yield and SOC between CC and no-cover crop treatments at both sites under irrigated and rainfed conditions. However, CC resulted in reduction of N loss by up to 48% at the Eastern Nebraska Research and Extension Center and 24% at South Central Agricultural Laboratory under irrigation. Cereal rye has no significant effect on total soil water but, a significant reduction in cumulative subsurface drainage of 44% was determined at both sites. This study has shown the possible effect of cover crop on corn crop yield and soil properties over different regions in Nebraska. Future research extending the scope and geographic area is needed to test and quantify possible impacts of multiple CC species under diverse management and biophysical conditions.