Peter C. Scharf and Victoria Hubbard. University of Missouri, Columbia, MO 65211
Previous research has shown that corn greenness in aerial photographs is related to the amount of N needed.  However, interference from soil color is an obstacle.  Waiting until canopy development minimizes soil interference is the simplest solution.  Unfortunately, at this canopy stage, additional N can be applied only with high-clearance applicators, airplanes, or irrigation systems.  Nitrogen application through pivot irrigation is inexpensive and is ideally suited to use aerial photos to guide decisions about N application rates.  The economic potential of this system is maximized if early-season N rates are modest.  One demonstration was conducted in 2006, and the producer saved $4000 in fertilizer costs while losing only 84 bu of estimated yield.  Six demonstrations are planned for 2007 and will be included in this presentation.