For nitrate-nitrogen reduction, the strategy presents a scenario in which MRTN adoption for applied nitrogen could reduce losses by 10% per acre. The Illinois Fertilizer & Chemical Association’s (IFCA) program is focused on identifying farmers to place nitrogen rate trials in their fields and ensuring proper implementation using University of Illinois protocols to ensure quality data collection. The Illinois Nutrient Research & Education Council (NREC) funds IFCA and the University of Illinois to manage the trials. Nitrogen rates of 0, 50, 100, 150, 200, and 250 pounds per acre are replicated three times in each field, and data collected at harvest determines the corn response to different applied nitrogen rates, timing, and sources. The U of I Department of Crop Sciences analyzes harvest data, which is uploaded online each year to the North Central Region Land Grant University Nitrogen Rate Calculator (cnrc.agron.iastate.edu). Individual field trial results from 2014–18 are also available (ifca.com/4R/Trials).
The map (Figure 4.36) illustrates locations of on-farm nitrogen rate trials performed in 2017-18 in all regions of the state. This map illustrates the north, central, and south climate and soil regions in the Nitrogen Rate Calculator. The central region also includes a rate recommendation for the Lake Springfield Watershed. Farmers can access the Nitrogen Rate Calculator online or as a free app to determine optimum economic and agronomic nitrogen rates.
The Illinois Fertilizer & Chemical Association also worked with NREC to develop a written guide for growers to explain how the MRTN system works, the science behind the recommended nitrogen rates, and myths about nitrogen use and loss (www.ifca.com/4R/Trials).
