McNay Research and Demonstration Farm
This project was designed to study the nitrogen (N) fertilization needs in continuous corn (CC) and corn rotated with soybean (SC) as influenced by location and climate. Multiple rates of fertilizer N were spring applied, with the intent to measure yield response to N within each rotation on a yearly basis for multiple years at multiple sites across Iowa. This will allow the determination of N requirements for each rotation practice, differences that exist between the two rotations, responses to applied N across different soils and climatic conditions, and evaluation of tools used to adjust N application.
Iowa State University
Sawyer, John E. and Barker, Daniel W., "Seasonal and Rotational Influences on Corn Nitrogen Requirements" (2007). Iowa State Research Farm Progress Reports. 894.