Effect of N:S ratio on the breadmaking quality of wheat: preliminary findings from 1999
Sulphur (S) is an important component of wheat proteins and, therefore, influences the quality of bread wheat. However, information regarding the role of S nutrition in Canadian Western Red Spring (CWRS) wheat cultivars under Western Canadian growing conditions is limited. Field experiments were conducted in Manitoba, Saskatchewan, and Alberta in 1999 and 2000 to examine the effect of S fertilizer application on grain yield, plant nutrient status, and bread-making quality of AC Barrie wheat (Triticum aestivum L.). Plant tissue and soil tests were also evaluated for their suitability in predicting grain yield and grain N:S ratio. Analyses of the 1999 grain samples indicated ranges of 25.3 to 38.7 mg g-1 in grain N content (14 to 22% in grain protein content), 1.3 to 2.2 mg g-1 in grain S content, and 14:1 to 23:1 in N:S ratio. Preliminary breadmaking quality analyses indicated that high ratios of N to S in grain were associated with lower loaf height, smaller loaf volume, greater dough resistance, and lower dough extensibility. Sulphur fertilization reduced grain N:S ratios at four of five sites. Of the three sites used to examine breadmaking quality, two sites showed significant improvements in loaf height and loaf volume where S fertilizer was applied. Sulphur fertilization also consistently reduced dough resistance and increased dough extensibility. The N:S ratio in grain was strongly correlated with N:S ratio in midseason tissue samples and N:S ratio in soil, calculated with water extractable NO3-S and SO4-S plus phosphate-borate extractable N and S. However, grain yield response to S was not well predicted by grain N:S ratio or spring soil test concentrations of sulphate-S.
Soils and Crops Workshop