| In order to understand N P K fertilizer response of the rice in medium-yield fields and lower-yield fields of Changsha suburb, the soil fertility of paddy field of Changsha suburb were analyzed in 2010, and a series of field experiments were carrid out to analyse the influence of different fertilizer amout on rice yield and rice agronomic characters and economic benefit. The main conclusions are as follows.(1) On the whole, soil fertility was higher in paddy soil of Changsha suburb with the pH ranged from 4.40 to 7.17,and averaged 5.52 and C.V was lower. The contents of soil organic matter, available N and available P were higher with uneven distribution, the contents of available K and slowly K were lower. Therefore,we should properly reduce the amouts of nitrogen fertilizer and phosphate fertilizr, and increase the amout of potassium fertilizer, and pay more attention to the balanced fertilization in the rice planting.(2) The results of field test showed that, nitrogen was the main limiting factor for the growth of rice, after that is was phosphate, potassium. Nitrogen and phosphate had great influence on rice agronomic characters, and potassium had less on that.(3) The results of medium-yield field treatment showed that, N2P2K2 had gaeatest yield,was 363.3 kg/667m, while N0P0K0had least yield, was 258kg/667m2. The accuracy of three-fertilizer efficiency model of N P K at a low level, but the single fertilizer efficiency modes of N P and K that was respectively Y=273.04+28.08N-2.01N2,Y=304.93+44.02P-9.18P2,Y=310.65+15.28K-1.581K2 were all more ideal.(4) The results of lower-yield field treatment showed that, N2P3K2 had gaeatest yield,was 294.6 kg/667m2, while N0P0K0had least yield, was 197.3kg/667m2. The accuracy of three-fertilizer efficiency model of N P K at a low level, but the single fertilizer efficiency modes of N P and K that was respectively Y=189.25+9.4N-0.46N2,Y=214.79+49.99P-8.00P2,Y=234.41+5.11K-0.18K2 were all more ideal. |
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