Residual effect of organic manure, phosphorus and gypsum application in preceding groundnut (Arachis hypogaea) on soil fertility and productivity of Indian mustard (Brassica juncea)

A field experiment was conducted during 1997–98 and 1998–99 to evaluate the residual effect of organic manure, phosphorus and gypsum application in preceding groundnut (Arachis hypogaea L.) on soil fertility and productivity of Indian mustard [Brassica juncea (L.) Czernj. & Cosson]. Groundnut crop received 0, 10 tonnes FYM and 5 tonnes poultry manure/ha as organic manure and 3 levels of P (20, 40 and 60 kg P₂O₅/ha). These 9 treatment combinations were kept in main plots and 3 gypsum levels (control, 250 kg/ha at sowing and 125 kg/ha at sowing + 125 kg ha at 35 days after sowing) in subplots. Residual effect of organic manure significantly increased branches/plant, siliquae/plant and 1,000-seed weight, and the seed yield of Indian mustard. The magnitude of increase in seed yield owing to residual effect of FYM and poultry manure was of 9.3 and 12.1% over the control. Residual effect of 60 kg P₂O₅/ha significantly increased siliquae/plant, seed weight/plant and 1,000-seed weight, and thereby the total seed yield of Indian mustard, which increased by 9.7% over 20 kg P₂O₅/ha. Significant improvement in yield attributes and seed yield of Indian mustard was also recorded where residual effects of gypsum treatments were applied compared with no gypsum residual.