Sulphur application does not improve wheat yield and protein concentration

Abstract

Grain protein plays an important role in the milling and baking quality of wheat (Triticum aestivum). The question is whether application of sulphur, an important constituent of proteins and amino acids, impacts wheat grain protein concentration. A 3-yr 10-site experiment was set up to determine if of sulphur (S) fertilization (0 and 25 kg S ha -1) affects Canada west red spring (CWRS) and Durum grain yield and protein levels, when combined with various rates of nitrogen (N) fertilizer (0, 40, 60, 80 and 100 kg N ha 1-). Soils at the 10 sites varied from S deficient to S sufficient, based on criteria in western Canada. Application of 25 kg S ha -1 resulted in no yield or grain protein concentration increases, regardless of the level of N fertilizer applied or the level of soil "available" S (0-30 cm). However, high N fertilizer rates (80 and 100 kg N ha -1) plus S fertilization improved yield and protein concentration when growing season (May, June, July) precipitation was favourable for CWRS and Durum wheat. In conclusion, we suggest that indiscriminate application of S fertilizer will not increase protein concentration for CWRS and Durum wheat grain.