Investigation of nitrogen and sulphur effects on quantitative and qualitative characteristics of castor bean seed (Ricinus communis L.)

In order to study effects of various levels of nitrogen and sulphur fertilizers on quantitative and qualitative characteristics of castor bean (Ricinus communis L.), an experiment was done in 2015 at reaearch farm, agricultural faculty of Azarbaijan Shahid Madani University, Tabriz-Iran. Experiment was conducted as a factorial based on randomized complete block design with three replications. Treatments were 4 levels of nitrogen (0, 50, 100 and 150 kg ha-1) and 5 levels of sulphur (0, 20, 40, 60 and 80 kg ha-1). Results indicated that maximum biological and seed yield, seed oil percentage and yield and appropriate percentage of seed crude protein obtained from applying 100 and 150 kg nitrogen per hectare. In contrast, application of 40 kg sulphur ha-1 was enough to reach maximum amounts in seed yield, HI, seed oil percentage and oil yield. Application of sulphur fertilizer had not significantly effect on seed crude protein. Maximum agronomic efficiency of nitrogen and sulphur was achieved when nitrogen and sulphur were applied at a rate of 150 and 40 kg ha-1, respectively. Interaction effects of nitrogen and sulphur showed that applying 150 kg nitrogen by 60 kg sulphur ha-1 resulted in the highest biological yield, seed and seed oil yield in castor bean. The overall conclusion of this experiment showed that presence of nitrogen and sulphur around the castor bean roots can cause an incease in leaf area, photosynthesis and biomass during the growing season, seed and oil yield at the end of the growing season.