To reduce contamination in groundwater and to optimize the effects of fertilization, researchers at North Carolina State University in Raleigh and in Plymouth have performed field tests of an aerial near-infrared imaging system for the site-specific management of winter wheat. They reported their findings in the January/February issue of Agronomy Journal.Near-IR imaging can determine the tiller density of winter wheat at growth stage 25, which may be used to indicate when nitrogen fertilization is needed. In the study, the scientists monitored the conditions of 978 field locations that included different varieties of wheat, soil colors and weeds. They found that the technique successfully indicated the need for fertilizer application 85.5 percent of the time.