Planting Date, Nitrogen Rate, and Nitrogen Timing Interactions to Optimize Winter Wheat Production.

Identifying nitrogen (N) fertilizer programs that account for autumn planting date and tiller production may improve the production and efficiency of winter wheat (Triticum aestivum L.) within the Great Lakes Basin. A 2014 field experiment was initiated in East Lansing, MI to determine the effects of planting date, N application timing, and total N rate on winter wheat yield potential. The study was arranged as a split-plot randomized complete block with four replications each containing 27 experimental units. Main plots consisted of three planting dates (17 Sept., 11 Oct., and 28 Oct. 2013) while sub-plots consisted of three N application timings (green-up, 50% green-up and 50% Feekes 5, and Feekes 5) and three N application rates (84, 118, and 151 kg N ha^-1). Data collection included weekly chlorophyll measurements, autumn and spring tiller counts, tissue sampling and nutrient analysis at Feekes 5 and 9, lodging ratings, disease incidence, grain head counts prior to harvest, grain moisture, test weight, and yield. Significant differences in autumn tiller counts (> 5, 1, and < 1) were observed for the Sept. and two Oct. planting dates, respectively. Additional field measurements and yield data will be discussed following the summer 2014 harvest season.