By: Daniel Kaiser, Extension specialist, and Fabian Fernandez, Extension specialist The corn nitrogen guidelines recommended by the University of Minnesota have recently been updated to include data from 2017 and 2018. The current guidelines use the Maximum Return to Nitrogen (MRTN) approach, which relies on a database composed of corn nitrogen response trials conducted across the state. The recent update includes the addition of 24 new sets of data for corn following soybean and 10 for corn following corn. The table below summarizes the revised N rate values. The addition of the new data resulted in a slight increase in the amount of N suggested for both corn/corn and corn/soybean rotations. Guidelines for use of nitrogen fertilizer for corn grown following corn or soybean when supplemental irrigation is not used (2019) Corn/Corn Corn/Corn Soybean/Corn Soybean/Corn N price/Crop value ratio MRTN Acceptable Range MRTN Acceptable Range 0.05