Evaluation of Optimal Nitrogen Application Rates Among Soil Types


  • The purpose of this study was to determine if productive soil types require more or less applied nitrogen (N)  than poor soils to maximize corn yield.

Study Description

Map: research trial locations

Locations:                12 in Indiana

Nitrogen Rates:       60 lbs/acre below grower standard

                                    30 lbs/acre below grower standard

                                    Grower-selected standard rate

                                    30 lbs/acre above grower standard

                                    60 lbs/acre above grower standard

  • An application prescription containing N rate blocks was created for each location using Pioneer® Field360™ Studio software.
Screenshot: application prescription
  • Grower-selected standard rates ranged from 170 to 200 lb N/acre.
  • Anhydrous ammonia was the N source for 9 of the 12 locations. Of the remaining 3 locations, 2 had a combination of urea and UAN applied while 1 was UAN. 7 of the 12 locations had preplant anhydrous ammonia applications.
  • Location average yields ranged from 160 to 261 bu/acre.
  • As-applied data and yield data were collected and analyzed using Pioneer Field360 Studio software.


  • The spring of 2013 was unusually wet, resulting in greater than normal N loss. Poorly drained soils had greater N requirements than well drained or drought prone soils.
Chart: 2013 yields
  • Within a soil series, the more eroded soil types had greater N requirements to maximize yields than their non-eroded counterparts. 
  • Although this is only 1 year of data, this observation lends support to the idea that soils with lower organic matter require greater amounts of N fertilizer to maximize yield.


Chart: Hosmer silt loan yields
Chart: Otwell silt loan yields

This was the first year of a multiyear study.

2013 data are based on average of all comparisons made in 12 locations through November 20, 2013. Multi-year and multi-location is a better predictor of future performance. Do not use these or any other data from a limited number of trials as a significant factor in product selection. Product responses are variable and subject to a variety of environmental, disease, and pest pressures. Individual results may vary.