Issue: Cover crops have significant potential to improve water quality by limiting erosion when row crops are not growing, and by limiting the loss of nitrogen by leaching. Yet widespread adoption has been limited, as the yield of subsequent-year corn crops may be negatively affected by cover crops. One reason for this is the potential for immobilization of nitrogen from soil organic matter as cover crop residues decompose.
Issue: Cover crops are a recognized conservation practice to reduce soil erosion, and Iowa research has shown a winter cereal rye cover crop greatly reduces nitrate loss with subsurface drainage. However, little research has evaluated the impact of cover crops on total and dissolved nitrogen (N) and phosphorus (P) loss with surface runoff.