Higher Nitrogen Rates Recommended for Minnesota Corn

By Scout Nelson

The University of Minnesota Extension has updated its recommended nitrogen fertilizer rates for non-irrigated corn after adding data from the 2022, 2023, and 2024 growing seasons. The new guidelines raise the suggested nitrogen application rate by about ten pounds per acre for both corn following corn and corn following soybean.

These updated figures appear in the revised Fertilizing Corn in Minnesota publication and on the Corn Nitrogen Rate Calculator. Farmers using the calculator may see slight differences of one to two pounds because of rounding.

The recommendations include an acceptable range to account for small profit differences, allowing flexibility within the Maximum Return to Nitrogen Rate (MRTN) approach.

The update applies mainly to non-irrigated corn grown south of Interstate 94. Producers in the Red River Valley are advised to continue following North Dakota State University guidelines for similar soils.

Research on irrigated corn shows little change in nitrogen needs, so current irrigated guidelines remain in place. Southeast Minnesota’s silt loam soils may require less nitrogen, making rates at the lower end of the range a good option.

The MRTN method focuses on the nitrogen rate that delivers the best economic return, balancing yield goals and input costs while protecting water quality. Choosing the profitable rate prevents unnecessary overapplication and limits nitrogen loss to the environment.

Researchers note that corn nitrogen requirements have gradually increased across the Midwest. From 1991 to 2021, the economic optimum nitrogen rate rose about 1.2% per year, closely matching grain yield growth. Wetter conditions may also play a role by causing nitrogen loss through denitrification in saturated soils.

This update emphasizes the importance of data-driven fertilizer management, helping Minnesota corn growers maintain profitability and environmental responsibility while meeting the crop’s evolving nutrient needs.

Photo Credit:university-of-minnesota