Northeast Research and Demonstration Farm
The purpose of this study was to evaluate the nitrogen (N) fertilization responses of four differing hybrids each year, rotated with soybeans, over a 3-yr period. Multiple rates of N fertilizer were spring applied, with the intent to measure yield response to N and nitrate concentrations at the end of the growing season. This allows the determination of N requirements for each corn hybrid and evaluation of N management practices over time.
Iowa State University
Ingels, Chad G. and Pecinovsky, Kenneth T., "Corn Response to Nitrogen Rates" (2007). Iowa State Research Farm Progress Reports. 915.