Effect of integrated nutrient supply on crop productivity and soil fertility in rice (Oryza sativa) wheat (Triticum aestivum) system in semi-arid and humid ecosystems

An investigation carried out for the last 6-10 years at 4 locations in rice (Oryza sativa L.)-wheat (Triticum aestivum L emend. Fiori & Paol.) cropping system indicated the possibility of substituting 50% N needs of rice through green-manures in semi-arid ecosystem at Ludhiana, Kanpur and Navasari with a small sacrifice in production. In humid ecosystem at Kalyani, all the organic sources, farmyard manures (FYM), crop residues and green-manures were able to substitute 25-50% N needs of rice with significant yield advantages in some cases. Continuous rice-wheat cropping led to decline in available N and K status, while it had variable effect on organic carbon and available P status, Integrated nutrient supply had favourable effect only on organic carbon status.