Site-specific nutrient management – a sustainable nutrient management option in rice, Oryza sativa L

Field experiment was conducted on rice, Oryza sativa L consecutively for four years during Kharif season of 2005–06, 2006–07, 2007–08 and 2008–09 on Godavari alluvials (Vertic chromusters) at Andhra Pradesh Rice Research Institute, Maruteru, AP on clay loam soil with the treatments of NPKB in different ratios. Application of NPKB @ 100-90-90-5 kg/ha recorded the highest number of filled grains per panicle, panicle length, 1000-grain weight, dry matter production at harvest, grain yield, higher root biomass, highest N, P and K uptake at harvest, energy input and energy gross returns and showed more stability in production. Reduction of P and K from 90 to 60 kg/ha did not affect the growth, yield parameters and grain yield of rice markedly but further reduction in dose of P and K from fertiliser schedule reduced the grain yield conspicuously. Omission of P and K fertilisers resulted in reduction of grain yield to the tune of 17.3 and 17.6 per cent respectively. Boron application failed to influence the grain yield conspicuously. Maintenance of soil fertility at healthy levels by supplying all nutrients in proportion matching with crop needs is one of the key steps in safeguarding high productivity on sustainable basis.