RESPONSE OF DIFFERENT LEVEL OF NITROGEN AND SULPHUR DOSES ON OIL YIELD AND SEED NUTRIENTS CONTENT OF SUNFLOWER (HELIANTHUS ANNUUS L.)

This research was performed to determine the response of nitrogen (40, 80, 120 kg N ha(-1)) and sulphur rates (0, 50, 100, 150 kg S ha(-1)) on oil yield and seed nutrients content of sunflower. The experiment design was in split plots of randomized complete blocks with three replications for two years. According to the results the lowest oil yield (0.66 t ha(-1)) was obtained with 40 kg N ha(-1) and 0 kg S ha(-1) while the highest oil yield (1.61 t ha(-1)) was from 80 kg N ha(-1) and 150 kg S ha(-1) application. The increase in oil yield parallel with increase the nitrogen doses to 80 N kg ha(-1) doses without sulphur and after this increase was stopped. But with the addition of sulfur doses, this increase higher and continued to 120 N kg ha(-1). The nitrogen and sulfur applications as compared to control increased the nitrogen and protein content of seeds by about 2%. The increase in nitrogen doses had a positive effect on nitrogen and protein content of seeds, though the increase in nitrogen content was become important after 100 kg S ha(-1) application. Seed phosphorus content varied between 0.44% and 0.545% in practice. The effects of sulfur doses and nitrogen x sulfur interactions on seed potassium content were significant and the seed potassium content varied between 0.574% and 0.960%. The effect of nitrogen and sulfur doses on the seed calcium content in sunflower was significant in both years and the seed calcium ratio was between 0.111% and 0.144%. The effect of sulfur doses on seed sulfur content in sunflower was significant in both years and the seed sulfur ratio was between 0.133% and 0.238%.