减量施氮对水稻生长和肥料利用效率的影响

目的]确定氮肥减量施用对巢湖流域水稻生长、氮肥利用效率的影响。方法]通过田间小区试验,以施氮量180 kg/hm2为基础,设置0、60%、80%和120%N施用量5个处理。在水稻成熟期,采集25株考种样,测定产量构成性状,并且测定每个小区籽粒产量。结果]适当减少氮肥施用量对水稻生长发育的影响不明显,2年试验水稻籽粒产量分别比对照提高-1.63%～1.92%和-2.36～2.57%,平均增产0.32%和0.34%,基本持平;氮肥偏生产力、农学效率、生理效率及表观利用率均明显提高,且随着氮肥施用量的下降而增大。结论]在当前生产水平下,在巢湖流域水稻土区适当减少氮肥施用量对水稻生长和籽粒产量影响不大,同时可明显提高氮肥利用效率,有利于环境保护。

Effect of Decreasing Nitrogen Application Rate on Rice Growth and Nitrogen Use Efficiency

Objective ] The aim was to determine decreasing application rate of nitrogen （N） fertilizer on rice growth and N use efficiency in Chaohu lake valley. Method] Five treatments of＂ different N application rates of 0, 60% , 80% and 120% on the basis of 180 kg N/hm2 were set up in the test. When rice was matured, 25 plants were randomly selected in each plot for inspecting the yield components, and seed yield every plot of rice were observed. Result] There was insignificant effect of reducing N application rate suitably on rice growth, seed yield in- creased by - 1.63 - 1.92% and -2.36 -2.57% averagely 0.32% and 0.34% respectively. N use efficiency of pal~ial factor productivity, agronomic efficiency, physiological efficiency and apparent recovery efficiency all improved, and increased with the dropping of N application rate. Conclusion] Effect of suitably reducing N application rate on rice growth and seed yield was insignificant in Chaohu lake valley, but N use efficiency could be improved obviously, which is benefit for environment protection.