The effect of sulphur deficiency on the uptake and incorporation of nitrogen in ryegrass

Abstract

SUMMARYSulphur deficiency reduced the yield and sulphur content of ryegrass at the fourth cut, while increasing the nitrogen content and N:S ratio. The distribution of the forms of nitrogen was also altered, with a decrease in the proportion of nitrogen recovered as amino acids and an increase in the concentration of asparagine. Amino acid analysis showed that the concentrations of the sulphur-containing amino acids cyst(e)ine and methionine were depressed by sulphur deficiency as well as those of arginine, histidine, lysine, glycine, leucine, serine and threonine. Sulphur deficiency, therefore, decreases the quality of crude protein found in grass, as well as reducing the yield.