Demonstrating Optimal Nitrogen Rate and Timing Practices in a Corn-Soybean Rotation

Wayne Dewall

This project will engage with an existing on-farm project designed to improve understanding of the impact of agricultural practices on water quality at both the field and small watershed scale.

Current two-year edge of field monitoring indicates that an average of 51 lbs. per acre is lost from the field each year. Greatest losses are in May and June when crop nitrogen (N) requirement s are low and heavy leaching rains are most common. The proposed project will examine opportunities to reduce nitrogen application from the current rate to the suggested maximum return to nitrogen (MRTN) rate developed by the University of Minnesota. The current average nitrogen rater, the MRTN suggested rate of N, will be applied as a single application and a third treatment where 60% of the MRTN rate will be applied pre-plant and 40% split applied in season will be compared in the project.

The goal is to demonstrate that more precise N rates based on MRTN will improve farm profit potential and minimize N loss to the environment.