Crop Research Station, N.D. University of Agriculture and Technology, Ghaghraghat, Bahraich, Uttar Pradesh.
A field experiment was conducted during 1999–2002 at Crop Research Station, Ghaghraghat, Bahraich to study the effect of integrated nutrient supply on yield, yield attributes, nutrient uptake and economics of rice (Oryza sativa L.)–wheat [Triticum aestivum (L.) emend. Fiori & Paol.] cropping system and soil fertility. Application of 25% recommended dose of N (RDN) through pressmud and the rest 75% NPK through inorganic fertilizers to both crops increased the grain yield of rice and wheat by 51.1 and 56.2% respectively over no NPK treatment. Addition of zinc with 100% of recommended NPK through inorganic fertilizers gave higher grain and straw yields of both rice and wheat over 100% of recommended NPK alone. The rice-equivalent yield and total uptake of N, P and K by rice-wheat system were highest with 25% RDN through pressmud + 75% RDF through inorganic fertilizers, followed by 50% RDN through pressmud + 50% RDN through inorganic fertilizers. The net income and benefit: cost ratios were also highest with 25% of recommended N through pressmud and the rest 75% NPK through inorganic fertilizer. The content of organic carbon and available phosphorus in soil improved in all integrated nutrient-management practices than its initial soil status. The value of potassium, bulk density, pH and electrical conductivity decreased in all the integrated nutrient-management practices compared with its initial soil status.
Integrated nutrient management, rice-wheat cropping system, Lowlands, Eastern U.P
