Integrated nutrient management in rice (Oryza sativa)-wheat (Triticum aestivum) cropping system

A field experiment, comprising 10 treatment combinations of 5 systems of ma nuring to rice (Oryza sativa L.) and 2 levels of NPK to wheat (Triticum aes tivum L. emend. Fori & Paol.) was conducted in rice-wheat cropping system d uring 1994-95 to 1996-97. Yield of rice varied significantly due to systems of manuring to rice but not due to level of NPK to wheat. Wheat yield, on the other hand, varied significantly due to both the systems of manuring to the preceding crop and the level of NPK to wheat. The system productivity was the maximum (79.18 q/ha rice-equivalent yield) with application of 100% recommended dose of NPK through fertilizer to both the crops. Combined app lication of green-manure and 50% NPK to rice and 100% NPK to wheat recorded identical system productivity indicating that 50% NPK of rice in rice-whea t system can be substituted by green-manure without appreciable sacrifice i n yield. Net monetary return and the benefit : cost ratio of the system wer e the maximum (Rs 13,962/ha and 1.64 respectively) with application of 100% NPK through fertilizer to each crop.