William Raun, John Solie, Randy Taylor, D.B. Arnall, and Starr Holtz. 368 Agricultural Hall, Oklahoma State University, Oklahoma State University, Dept. of Plant & Soil Sciences, Stillwater, OK 74078-0507
Since 1992, our sensor-based variable N rate research team has evaluated many strategies of N management in corn and wheat production.� Some have worked and others have been complete failures.� Early on, a linear scale applying higher N rates at low NDVI and low at high NDVI values was developed.� While this approach reduced rates, increased yields were not obtained.� When we finally recognized that rates needed to be tied to projected yields, and estimated N responsiveness using N Rich Strips, yield increases were observed at lower N rates.� Most recently, capturing statistical information, by-plant (using NDVI sensors), has assisted in refining N rates when variable rate technologies are employed.�