Diversification of rice (Oryza sativa) wheat (Triticum aestivum) system for improving soil fertility and productivity

A field experiment was conducted during 1996 97 to 1999 2000 at Karnal, to evaluate the effect of 6 rice (Oryza sativa L.) based crop sequences on soil fertility and productivity. Maximum wheat equivalent yield was re corded by inclusion of potato (Solanum tuberosum L.) (197.1 200.3 qlha), followed by vegetable pea (Pisum sativum L.) (173.5 173.8 qlha) between rice and wheat (Trticum aestivum L. emend. Fiori Paol.) crops. These systems resulted in additional wheat equivalent yield of 48 71 qlha over the rice wheat system. Continuous incor poration of Sesbania aculeata as green manure increased organic carbon by 8.7%, available N by 12.1%, Olsen s P by 10.1 % and available K by 5.0% in soil compared to rice wheat sequence. Growing of vegetable pea and po tato between rice and wheat also increased organic carbon by 8.9 and 17.1%, available N by 6.3 and 8.3% qnd available P by 6.3 and 19.0%, respectively, compared to rice wheat system. Green manuring with Sesbania aculeata added 97 109 kg Nlha and enhanced the wheat equivalent yield in the rice wheat system. Electrical conductivity and pH of soil decreased due to the inclusion of vegetable rice, potato and green manure.