Integrated nutrient management in cotton (Gossypium hirsutum)-wheat (Triticum aestivum) sequence on Ver tisol

A field experiment was conducted under irrigated condition on intergrated nutrient management system for cotton (Gossypium hirsutum L.) - wheat (Triticum aestivum L. emend. Fiori & Paol.) sequence on Vertisol at Rahuri, during 1999-2000 and 2000-2001. Application of 100% recommended dose of fertilizer (RDF) recorded significantly higher seed-cotton yield (20.68 qlha), stalk yield (47.76 qlha ), nutrient uptake and soil available NPK after cotton over 75% RDF. Similarly, wheat grain yield (45.68 qlha), straw yield (58.1 1 qlha), wheat-equiva- lent yield (109.03 qlha), net monetary returns, benefit : cost ratio, nutrient uptake and soil-available NPK after wheat were recorded highest with 100% RDF to cotton. Application of 10 tonnes FYMIha to cotton recorded the highest cotton wheat and wheat-equivalent yield, nutrient uptake and soil-available NPK after cotton and wheat. However, it was at par with treatment green-manure + Azotobacter+ phosphate-solubilizing bacteria except for P uptake in cotton. The later treatment gave the highest net monetary returns and benefit : cost ratio. Application of 75% RDF to wheat gave grain and straw yields, wheats equivalent grain yield, nutrient uptake and soil-available NPK after wheat at par with 100% RDF, but the higher net monetary returns and benefit : cost ratio (Rs 2.20). Af- ter sequence the net gain of soil-available N was increased with decrease levels of fertilizer and manures to cot- ton and increased with increased levels of fertilizer to wheat. The magnitude was increased with increased levels of fertilizer and manures with respect to net gain of soil available P. While net loss of soil-available K, the magni- tude of reduction was decreased with increased levels of fertilizer and manure.