Integrated nutrient management for rice-wheat cropping system in a recently reclaimed soil

A field experiment was conducted for integrated nutrient management in a recently reclaimed soil. For thispurpose a saline sodic field was selected at soil salinity research farm having ECe, 7.40 (dS m-1); pHs, 8.90; SAR,38.26 (mmol L-1) and gypsum requirement, 3.52 (ton acre-1); deficient in total nitrogen (0.017%) and availablephosphorus (4.20 mg kg-1) and medium in extractable K (90 mg kg-1). This field was reclaimed by applying gypsumat 100% G.R. After reclamation, different combinations of FYM, Sesbania and chemical fertilizers were applied.The experiment was layed out in randomized complete block design with three replications. Rice variety Shaheenbasmati was transplanted. The data showed that different combinations of organic manures with chemical fertilizersincreased paddy and straw yield significantly over application of organic manures alone. Among differentcombinations, Sesbania at 20 ton ha-1 + 75% recommended dose (R.D.) proved to be the best combination followedby Sesbania 20 ton ha-1 + 50% R.D. and least in FYM alone at 20 ton ha-1. It was also noted that sesbania greenmanuring alone was found superior to FYM alone. The NPK contents both in paddy and straw were increasedsignificantly by applying various combinations of organic manures with chemical fertilizers over application oforganic manures. Maximum contents of NPK both in paddy and straw of rice were recorded in the combination ofSesbania at 20 ton ha-1 + 75% R.D. followed by Sesbania 20 ton ha-1 + 50% R.D. and least in FYM alone at 20 tonha-1.The soil analysis after harvest of rice showed that it was still slightly sodic in nature but free from salinity,deficient in total N and available P but adequate in extractable K. After harvest of rice crop in the same layoutwheat variety Inqulab 91 was sown. Percent recommended dose of NPK was applied to all the plots as per treatmentplan to see the residual effect of the organic manures applied to rice crop. Crop was harvested at maturity. Theresults of grain and straw yield showed that different combinations of organic manures (residual) and chemicalfertilizers increased grain and straw yield significantly over alone application of organic manures (residual).Recommended dose of chemical fertilizers alone applied to wheat gave the maximum yield of grain and strawfollowed by combinations of FYM at 20 ton ha-1 + 75% R.D (residual) which was non significant with FYM 20 tonha-1 + 50% R.D (residual) combination and least in FYM and Sesbania alone at 20 ton ha-1 (residual). The NPKcontents both in grain and straw were increased significantly by a