MRTN Rate Calculator

This guide explains how we use nitrogen research results to generate N rate recommendations (or guidelines) for corn in Illinois. This system represents a research-based but "common sense" approach to nitrogen—we have enough research to replace the "do I have enough N?" question with "what is the best strategy?" for nitrogen management on your farm. This system is based on nitrogen rate trials performed on farmers' fields and at University of Illinois research centers throughout the state. The data from these trials are used to update the Nitrogen Rate Calculator in order to keep it current with the latest research results. Many people understand the concept of using data from research to predict how a management factor will work the next time; that's the whole reason we do applied research. But responses to N are highly variable across even nearby fields within the same year, and across years even within the same field. This variability makes it challenging to predict how much N will be needed in any field, even in the same field from one year to the next. Since 2012 this research has been funded by the Illinois Nutrient Research & Education Council, whose support has helped to accelerate the building of the database, and hence the improved soundness of the N rate guidelines. NREC emphasizes the importance of research that engages farmers in the research process, on their production fields. This helps assure that the results are based upon real life corn nitrogen responses. This guide explains the terminology and the process for determining the Maximum Return to Nitrogen (MRTN), which is the N rate that maximizes the dollar return to N. We also address commonly asked questions and dispel myths about nitrogen use, all in an effort to support sound agronomic principles, and to increase economic return while respecting our environment.