Response of Legume and Oilseed Crops to Different Sources of Sulphur and Magnesium in Some Alluvial Soils

Direct and residual effects of sulphur and magnesium were studied in pot culture experiment in a three-crop sequence of legumes and oilseed on three soils of alluvial origin. Cowpea responded to direct application of sulphur by increasing both dry matter yield and S uptake, irrespective of the sulphur status of the soils. Residual effect was similarly beneficial to mustard as second crop in the sequence in soils comparatively richer in available sulphur. Moong or green gram (Phaseolus aureus Roxb.) raised as the third crop showed greater uptake of S particularly from calcium sulphate. In general, ammonium sulphate proved to be better source of sulphur closely followed by potassium schoenite. Application of magnesium did not result in significant increase in yield but its uptake was higher in cowpea and mustard when added along with sulphur indicating a synergistic type of relationship.