Illinois Fertilizer & Chemical Association
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MRTN Explained!

The Maximum Return to Nitrogen (MRTN) Calculator is a key part of Illinois' nutrient recommendation system.  Ensuring we are not over applying nitrogen is essential to helping us reach the 2025 goal of reducing nitrogen losses by 15%.  We are making great progress toward that goal but we have to stay committed to the voluntary practices that will get us there.
Dr. Nafziger at the University of Illinois has prepared an explanation of the MRTN, and addresses the common questions asked about the N Rate Calculator.  Yes it is based on corn yield!  It also takes many other things into consideration and a great explanation of the science behind the MRTN is available in today's bulletin from UI, click here.  
As we begin to think about next year's corn crop, now is a great time to revisit the MRTN and see what the optimum rates are for your region of the state.  Thanks to NREC's support for N rate trials throughout the state, the Illinois MRTN reflects the most recent data, from actual farm trials, on yield response to nitrogen and determines the sweet spot both agronomically and economically.  Before NREC, Illinois' nutrient recommendation system was treading water, with no funding to keep this essential research going to support nutrient decisions.  But now with NREC funding, our Land Grant guidance for N, P and K rates is among the most current in the entire Midwest.  Take advantage of this updated, science based system and check out all the nutrient updates at our Keep it 4R Crop menu at