McNay Research and Demonstration Farm
This project is designed to study the nitrogen (N) fertilization needs in continuous corn (C-C) and corn rotated with soybean (C-S) as influenced by location and climate. Multiple rates of N fertilizer applied in the spring, with the intent of measuring yield response to N within each rotation on a yearly basis for multiple years at multiple sites across Iowa. This system will allow the determination of N requirements for each rotation practice, differences that exist between the two rotations, responses to N applied across different soils and climatic conditions, and evaluation of tools used to adjust N applications.
Iowa State University
Sawyer, John E. and Barker, Daniel W., "Seasonal and Rotational Influences on Corn Nitrogen Requirements" (2005). Iowa State Research Farm Progress Reports. 1221.