By Matt Hutcheson, CCA, Product Manager, Seed Consultants, Inc.
Application timing and amount are key factors in achieving high winter wheat yields. While the amount of N required in the fall is relatively small, it is critical to promoting early development and tillering. With spring weather around the corner, winter wheat producers will be gearing up for spring topdress of their wheat crop. Timing and rates are critical in the spring as to maintain the high yield potential of winter wheat varieties.
Spring applications of N should be made after the plants break dormancy. Although in some situations field conditions may be favorable, nitrogen applied in the late winter before plants have broken dormancy is more likely to be lost before plants can utilize it. Spring N applications should not be made before wheat has broken dormancy and begins to green up. The University of Kentucky publication “A Comprehensive Guide to Wheat Management in Kentucky” recommends: “When making a single N fertilizer application the best time is when the crop growth stage is Feekes 4-5, (Zadoks 30, usually mid-March) just before the first joint appears on the main stem and when wheat starts growing rapidly.” The UK publication goes on to say that “The rate of N fertilizer for a single application should be between 60 and 90 lb N/acre for fields with a yield potential less than 70 bu/acre and 90 to 100 lb N/acre for fields with greater yield potential.”
Wheat plants begin a period of rapid growth and stem elongation once they reach Feekes Stage 6 (first node visible). The plant’s demand for N is high as the stem elongates and rapid growth begins. For optimal use of inputs and to achieve the highest yield potential, spring N should be applied in the period of time following green up prior to stem elongation.