Abstract
A field experiment on a rice-rice (Oryza sativa L.) system in _permanent plots conducted over 9-10 years at four locations in eastern and southern India indicated that it is possible to substitute 50% of the N needs of the monsoon crop as organic sources such as farmyard manure (FYM) and green manure in acid soils but not in alkaline soils. In the hot humid region with acid soils rice straw can be used to substitute 25-50% of the N needs of the monsoon crop in the rice-rice cropping system. Integrated use of inorganic and organic fertilizers increased soil organic C status but had no marked effect on available P and K contents. Integrated use of FYM and rice straw with chemical fertilizers had a more favourable effect on nutrient balance, than use of green manure with chemical fertilizers.
