Modeling Cereal Rye Cover Crop Impacts on Soil Erosion, Nutrient Losses, and Crop Yields Across U.S. Corn and Soybean Production Areas

Cover crops are increasingly promoted to improve soil health, reduce nutrient losses, and enhance water quality, yet their large-scale performance across diverse climatic and soil conditions remains insufficiently quantified. We hypothesized that cereal rye cover crop adoption would reduce sediment and nutrient losses, with potential impacts on cash crop yields, and that these effects would vary with precipitation regime and soil vulnerability. Using Conservation Effects Assessment Project data and Agricultural Policy/Environmental eXtender simulations across 4317 U.S. corn and soybean sites over 45 years, we evaluated two scenarios: current management (Base) and Base plus Cover Crop (BCC). Stratification by precipitation group and Soil Vulnerability Index enabled assessment of context-dependent responses. Simulations showed substantial reductions in sediment losses (up to 60%) and surface nitrogen losses (≈30%) under the BCC scenario, with the strongest benefits in wetter regions and highly vulnerable soils. Soluble phosphorus decreased modestly (≈9%), and nitrogen retention improved under low-to-moderate leaching vulnerability. Yield reductions were limited (6–7%) and were smallest in drier regions where irrigation mitigated water stress. Overall, cereal rye cover crop adoption delivered meaningful soil and water conservation benefits with measurable yield impacts, supporting its role as an effective and scalable conservation practice across diverse U.S. agroecosystems.