Mid-season Recovery to Nitrogen Stress in Winter Wheat

Abstract

Winter wheat yields are directly affected by the amount of nitrogen (N) that is available to them for growth. Past research has indicated that spring application of N is more effective than fall application for winter wheat. This experiment was conducted to determine if potential yield reductions from early season N stress can be corrected using in-season N applications. Three experimental sites for two growing seasons (6 site - years) were used to evaluate 3 preplant N rates (0, 45, and 90 kg ha-1) and a range of in-season topdress N rates. Topdress N amounts were determined using a GreenSeekerTM hand held sensor and an algorithm developed at Oklahoma State University. Even when early season N stress was present (0-N preplant) N applied topdress at Feekes 5 resulted in maximum or near maximum yields at 4 of 6 sites when compared to other treatments receiving both preplant and topdress N.