A second year of research is underway to validate the Maximum Return to Nitrogen (MRTN) calculator as an effective tool for determining nitrogen (N) rates in corn, especially in corn/soybean rotations with and without cover crops. This research is particularly important for farmers in central Illinois, where tile-drained fields require efficient nitrogen management to minimize nitrate loss. 

Dan Schaefer, director of nutrient stewardship at the Illinois Fertilizer & Chemical Association, is leading the project. According to Schaefer’s update in early March, the project faced challenges with cover crop planting last year due to wet weather, pushing cereal rye planting into December. Despite the cold temperatures in February, the rye is now beginning to green up, with plans to terminate the cover crop and apply nitrogen treatments in time for corn planting. Soybean cover crops will also be terminated in early April to allow for soybean planting. 

Schaefer emphasizes that the study’s findings confirm that high nitrogen rates are unnecessary for achieving high yields. “Farmers in the central zone can expect to see good results with approximately 180 lbs of N per acre, with the MRTN calculator remaining accurate within a 10 lb margin,” Schaefer noted. 

This ongoing research, funded by the Illinois Soybean Checkoff, highlights the importance of efficient nitrogen use, particularly in tile-drained soils. For more details on the MRTN calculator and this study, visit the Field Advisor Research Hub.