Managing Water and Nitrogen in No-till Corn Production with a Cereal Rye Cover Crop.

Reducing inorganic nitrogen (N) loads from agriculture is of paramount concern to residents, farmers, and policy makers in the Chesapeake Bay region. Cover crops can mitigate the excess N loading from agriculture by utilizing soil N that would otherwise be prone to leaching. Delaying termination in the spring may increase the benefits provided by the cover crop but can also result in negative management trade-offs. The larger biomass results in potential for greater carbon sequestration, water infiltration and storage and N scavenging. However, the larger cover crop can immobilize N in the soil and delay its availability to the corn crop. Furthermore, bigger covers can potentially draw down spring soil moisture with implications for water stress in corn. Therefore, we designed an experiment to quantify the trade-offs in water and N management of implementing cover crops and increasing the duration of cover crop growth in the spring. We examined cover crop effects on water availability, N distribution in the soil profile (to 100 cm), and N release throughout the growing season in a no-till corn production system. By evaluating the effects of the presence of a cereal rye cover crop and termination timing on N and water availability, the data can be used to improve recommendations to farmers about cover crop residue management.