Maximizing yields in rice–groundnut cropping sequence through integrated nutrient management

Abstract Integrated use of organic and inorganic fertilizers can improve crop productivity and sustain soil health and fertility. The present research was conducted to study the effects of application of green manures [sesbania ( Sesbania aculeate Poiret) and crotalaria ( Crotalaria juncea L.)] and farmyard manure on productivity of rice ( Oryza sativa L.) and its residual effects on subsequent groundnut ( Arachis hypogaea L.) crop. Rice and groundnut crops were grown in sequence during rainy and post-rainy seasons with and without green manure in combination with different fertilizer and spacing treatments under irrigated conditions. The results showed that application of green manures sesbania and crotalaria at 10 t ha −1 to rice compared to no green manure application significantly increased grain yield of rice by 1.6 and 1.1 t ha −1 , and pod yields of groundnut crop succeeding rice by 0.25 and 0.16 t ha −1 , respectively. There was no significant difference between the application of crotalaria or farmyard manure at 10 t ha −1 on grain yields of rice, but pod yields of subsequent groundnut crop were greater with application of green manure. There was no significant effect of different spacing 20×15,15×15,15×10 cm 2 (333 000; 444 000; 666 000 plant ha −1 , respectively) on grain yield of rice. Pod yields of groundnut were significantly greater with closer spacing 15×15 cm 2 (444 000 plants ha −1 ) as compared to spacing of 30×10 cm 2 (333 000 plants ha −1 ). Maximum grain of rice was obtained by application of 120:26:37 kg NPK ha −1 in combination with green manures, whereas maximum pod yield of groundnut was obtained by residual effect of green manure applied to rice and application of 30:26:33 kg NPK ha −1 in combination with gypsum applied to groundnut crop.