The predominant corn-soybean production system in Iowa has been shown to be a major source of nitrate moving to surface waters via tile drainage and subsurface water. Farmers need viable crop production systems for economic profitability. The easiest transition regarding in-field practices to improve water quality, and most economically profitable, will be most widely adopted. Winter cereal rye is used as a cover crop and can be used as a seed crop for feed and human food. This project will focus on a cropping system that can incorporate three important nitrogen reduction practices: cover crop, longer rotation/small grains, and nitrogen rate. Specific objectives are to determine the nitrogen fertilization rate for cereal rye seed production, effect of under-sown red clover on the rye optimal N rate requirement, impact of red clover cover crop on corn optimal N fertilization requirement and yield, and influence of the cropping system on soil nitrate-N.
John Sawyer is a professor in the Department of Agronomy at Iowa State University, coming to ISU in 1998. He earned a bachelor's degree in soil science at The Ohio State University; and earned a master's and doctorate in agronomy at the University of Illinois. Sawyer's Extension and research programs focus on soil fertility management, efficient crop nutrient utilization with an emphasis on nitrogen management, and also economically and environmentally sound fertilizer and manure nutrient management systems.
Antonio Mallarino, ISU Department of Agronomy