Top-dressing durum with nitrogen to manage protein

Abstract

Grain protein is an important factor in determining the quality of durum wheat (Triticum turidum L.). Durum markets pay a premium for protein content of 13% or higher. During the 1990's, the average protein content of durum produced on the Canadian prairies has been 12.5% or less, leaving a sizable proportion of the durum crop unsuitable for the premium market. The overall objective of this project is to determine the effect and relative efficiency of top-dressed N on grain protein, quality, yield, and economic return of durum wheat. Nitrogen at three rates (20,40 and 60 kg N ha-1) was top-dressed on durum at 4 growth stages; before germination (during seeding), five leaf, flag leaf and flowering. The study was done over three years at two locations (Indian Head and Swift Current, SK). Four cultivars were used. Increasing the rate of top-dressed nitrogen increased the protein content of the durum. Applying all the nitrogen at seeding provided the most consistent increases in protein. However, when the yield potential increased during the growing season due to above normal spring and summer precipitation, protein levels in the durum seed increased when nitrogen was top-dressed during the growing season.