No‐Till Winter Wheat Production on the Canadian Prairies: Timing of Nitrogen Fertilization

Abstract

AbstractThe introduction of a practical snow management system, which uses direct no‐till seeding into standing stubble immediately after harvest of the previous crop, has permitted northward expansion of the North American winter wheat (Triticum aestivum L.) production area to include most of the western Canadian prairies. Twenty‐one broadcast ammonium nitrate fertilizer field trials were conducted in Saskatchewan from 1976 to 1986 to determine what influence timing of N fertilizer application had on grain yield, grain protein yield, and grain protein concentration of no‐till winter wheat. Time of N application had a significant influence on all three variables in approximately one‐third of the trials. Lower grain yield, grain protein yield, and grain protein concentration were attributed to loss of fallapplied N in four trials. In one trial, a prolonged period without rainfall left N temporarily stranded in a dry surface soil layer and lowered yield for early spring fertilizer application. Delays in spring N application also limited grain and grain protein yield‐N responses. However, dry spring conditions and late fertilizer applications did not limit grain protein yield to the same extent as it did grain yield. Therefore, increased grain protein concentration was often associated with delayed N availability. Reduced grain and grain protein yield, and increased grain protein concentration were observed for fall and early spring N applications in trials that experienced favorable spring growing conditions followed by a prolonged drought. Under these conditions maximum grain protein concentration ranged from 170 to 230 g kg−1, compared with approximately 150 g protein kg−1 dry grain under normal growing conditions.