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Lake Springfield is the First Watershed in Illinois with Its Own MRTN

5/18/2017

Illinois Fertilizer and Chemical Association staff Dan Schaefer and Jason Solberg provided their agronomic expertise to CBMP during the three year Lake Springfield Watershed project, from 2014-2016.  Their role was to work with farmers to implement nitrogen rate trials to the growers’ confidence in using the Maximum Return to Nitrogen (MRTN) recommendation system.  

The goal of the Lake Springfield project is to keep the nitrate levels in the Lake below 5 ppm; improving nitrogen utilization and incorporating the 4Rs (Right Source, Right Rate, Right Time, Right Place) was one component of the project.  After three years of nitrogen rate trials in the watershed, there was enough yield data from the trials for the University of Illinois to develop a MRTN specific to the watershed.  Dan Schaefer of IFCA presented the results of the new MRTN at the Lake Springfield Watershed Partners meeting held December 7, 2016. 

Why is this so significant?

Lake Springfield is the source of drinking water for our state Capitol and the lake is managed by a municipal utility:  City, Water, Light & Power (CWLP).  By comparison, the Des Moines Waterworks supplies water to Iowa’s Capitol city (Des Moines) and when nitrates became a problem there we all know what happened when the Waterworks felt that agriculture wasn’t being proactive on reducing nitrogen losses—they sued.  But the Waterworks could still remove excess nitrate with treatment, and CWLP cannot.  If Lake Springfield ever goes over 10 ppm nitrate, it will require bottled water to be distributed the citizens of Springfield and surrounding communities.  We never want to get to that point! 

The Illinois Nutrient Loss Reduction Strategy (INLRS) lists using the MRTN “first” on the list of activities to reduce nitrogen losses to water. 
With Lake Springfield being such a high priority area for reducing nitrate losses, it was vital to ensure that farmers can be confident in using the MRTN.  The Nitrogen Rate Calculator is supported by Land Grant Universities in the North Central United States, including the University of Illinois. 

March17MRTNrates.pngThe MRTN for the Lake Springfield Watershed (LSW) is now featured as its own region under the Illinois section of the website, located at http://cnrc.agron.iastate.edu/  At current prices, the MRTN for the LSW for corn following soybeans is slightly lower than the Central Illinois MRTN (166 lbs compared to 172 lbs) and for corn following corn, it is slightly higher (202 lbs compared to 200 lbs).  See the comparison chart below, provided by the University of Illinois Department of Crop Sciences. 

In Ohio, farmers and retailers in the Western Lake Erie basin MUST use the Ohio State nitrogen recommendations, it’s the law.  If that were ever to happen in Illinois, it’s absolutely in our best interest to ensure our MRTN is the best system it can be to achieve and balance production, economic and environmental goals. 

CBMP encourages farmers and crop advisers to follow the 4Rs for nitrogen management and that begins with the Right Rate.  Most of the visit to the Nitrogen Rate Calculator occur in October, March and April, when nitrogen decisions are being made.  A new map of Illinois is also featured at the MRTN website (below) and delineates the MRTN regions in the state:  North, Central, LSW and South.  The MRTN for all of these regions continues to be updated with nitrogen rate trial data from on-farm trials that are supported by NREC.  For questions about the MRTN, please contact IFCA at (309) 827.2774. 

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