Production System Techniques to Increase Nitrogen Use Efficiency in Winter Wheat*

Most current research on winter wheat (Triticum aestivum L.) focuses on increasing yields of either grain or plant biomass. Increased production costs and environmental awareness will promote the development of methods to increase the efficiency of applied nutrients. Nitrogen (N) is often the most limiting nutrient for cereal grain production and represents one of the highest input costs in agricultural systems. This study was conducted to evaluate the effects of several short-term practices on nitrogen use efficiency (NUE) in winter wheat at three locations in Oklahoma. The variables evaluated included variety, nitrogen source, nitrogen timing, nitrogen rate, production system (forage only vs. grain only and a combination of the two), resolution of