Concepts and Rationale for Regional Nitrogen Rate Guidelines for Corn

Nitrogen (N) is typically one of the largest corn fertilization expenses. Nitrogen application is critical because it significantly improves corn yield in many crop rotations. When choosing N rates, producers need to carefully consider both achieving most profitable economic return and advancing environmental stewardship.\nIn 2004, university agronomists from the Corn Belt states began discussions regarding N rate use for corn production. The reasons for the discussions centered on apparent differences in methods for determining N rates across states, misperceptions regarding N rate guidelines, and concerns about application rates as corn yields have climbed to historic levels. An outcome of those discussions was an effort with the objectives to:\n▪ develop N rate guidelines that could be applicable on a regional basis and\n▪ identify the most profitable fertilizer N rates for corn production across the Corn Belt.\nThis publication provides an overview of corn N fertilization in regard to rate of application, investigates concepts for determining economic application rates, and describes a suggested regional approach for developing corn N rate guidelines directly from recent research data.