Yield, nutrient concentration and quality of mustard crops as influenced by nitrogen and sulphur fertilizers

Summary Field experiments were made for 3 years (1975–8) on soils deficient in both available N and S to test the effects of these nutrients applied as fertilizers on yellow mustard (Brassica campestris L.) and mustard (Brassica juncea L.). In all the 3 years, grain yield of both mustard crops significantly increased with increased N rates. The grain response to added S was not consistently significant, however; maximum yields were obtained only when high rates of N and S were applied together. N and S fertilizer significantly increased the concentration and uptake (kg/ha) of N and S in grain, and there was a significant positive N × S interaction. Adequate N/S ratio appears to be 7·5:1 or less for the grain of these mustard crops. Protein content of grain improved markedly with applied N and S. Application of 60 kg S/ha increased the oil content by 12% in yellow mustard and 16% in mustard. Although N had little effect on percentage oil, total oil production increased many fold. The combined application of N and S had the largest effect in determining the concentration and uptake of N and S, and on protein and oil content in grain. This study indicated that additions of 60 kg S/ha to mustard crops receiving adequate fertilizer N are likely to improve their yield and quality.