Effect of incremental doses of fertilizers on nutrient uptake and quality parameters of Kharif rice, Oryza sativa L on deltaic soils of Andhra Pradesh

Field experiments were conducted on rice, Oryza sativa L for three consecutive Kharif seasons viz 2006, 2007 and 2008 on Godavari alluvials (Vertic chromusters) at Andhra Pradesh Rice Research Institute, Maruteru with an objective to study the effect of incremental doses of major fertilizers on Kharif rice in Krishna Godavari delta regions of AP. Incremental doses of N, P and K over the recommended doses recorded significant improvement in uptake, post soil nutrient status and grain quality parameters. Increase in N dose by 25 per cent over recommended dose increased the uptake of P and K conspicuously besides increase in uptake of N. Similarly increase in K dose by 25 per cent resulted in marked improvement in N uptake also. The status of available P and K was significantly improved by enhancing P and K levels to 150 per cent from 100 per cent in case of potassium and both the levels of 100 per cent and 125 per cent with regard to phosphorus. There was the buildup of available P and K in soil by increasing P and K dose by 50 per cent and above over present recommendation. Grain quality in terms of grain protein content increased progressively with the incremental doses of N and P. The milling characters were significantly influenced by incremental doses of N, P and K. Hulling (%) was significantly improved up to first incremental dose of N (125%). The milling (%) and per cent head rice recovery increased N up to 50 per cent though the differences were conspicuous up to 25 per cent N increase.