Establishing Nitrogen Credits Following a Sweet Corn Crop on Non-Irrigated Soils
Study Author(s): Carl Rosen, University of Minnesota, Department of Agronomy and Plant Genetics
Years of study: 2017-2020
Important: for the complete report, including all tables and figures, please download using the links to the right.
Based on this three-year study, we can conclude that field corn following field corn had a much higher nitrogen requirement than field corn following soybean and field corn following sweet corn with or without rye as a cover crop. The nitrogen credit for sweet corn is about 15 lbs less than that for soybean. Currently the soybean nitrogen credit is about 35-40 lb N/A. Therefore, a safe nitrogen credit for sweet corn would be about 20-25 lb N/A. If rye is used as a cover crop following sweet corn, the rye should be terminated by before May 10 to ensure that a nitrogen credit can be taken. If rye is not terminated by May 10, then a nitrogen credit should not be taken for a previous sweet corn crop. Use of rye following sweet corn resulted in lower residual nitrate in the soil in the fall and the following spring and therefore would reduce the potential for nitrate leaching during the months after sweet corn harvest and prior to planting of field corn.