Effects of different nitrogen application levels on the biological yield and n use efficiency of super rice in northern China | 不同氮素水平对北方超级稻物质生产及氮素利用率的影响

chinois. 以北方超级稻铁粳7号和沈农265为试材,分析了不同氮素水平对群体物质生产及氮素利用率的影响。结果表明:与当地施纯氮量210kg•hm-2相比,降低30%的氮素水平(147kg•hm-2)未造成铁粳7号和沈农265的产量显著下降,从抽穗期至成熟期两品种的叶、茎鞘干物质输出率和对产量贡献率下降,而穗干物质增量呈现增加趋势,表明该氮素水平可以促进营养器官光合同化产物对生殖器官的直接供应能力;降低30%氮素水平下铁粳7号和沈农265的氮素分配比例都表现出穗部积累优势,氮素收获指数、生理利用率、农学利用率、偏生产力分别增高6.3%、15.8%、3.8%、25.4%和5.8%、25.2%、1.7%、23.2%,而总吸氮量、氮素回收率分别降低14.0%、11.1%和8.4%、9.7%。可见当地施氮素量偏高,在不明显降低产量的前提下降低施氮量,可以提高氮素转化为经济产量的能力,避免水稻植株"奢侈"耗氮,有益于氮素利用率和产谷效率的协同作用,提高经济效益。

anglais. The super rice varieties of ’Tiejing 7’ and ’Shennong 265’ were used to study the matter production,yield and N use efficiency under different nitrogen application levels.The results showed that nitrogen level decreased by 30%(147kg•hm-2)compared to local nitrogen application 210kg•hm-2 did not reduce the yield significantly.The output rate of dry matters of leaf,stem and sheath of ’Tiejing 7’ and ’Shennong 265’ and contribution rate to yield had dropped,but the dry matter accumulation of ear showed an increasing trend from heading stage to maturation stage under nitrogen level decreased by 30%.The nitrogen level could promote the direct supply capacity of photosynthetic product from vegetative organs to reproductive organs.The distribution rate of nitrogen of two varieties showed advantage of ear accumulation under nitrogen level decreased by 30%.The nitrogen harvest index,physical efficiency,agronomic efficiency,partial productivity increased 6.3%,15.8%,3.8%,25.4% and 5.8%,25.2%,1.7%,23.2%,while the total nitrogen accumulation and apparent nitrogen recovery efficiency decreased 14.0%,11.1% and 8.4%,9.7% respectively.The result indicated that local nitrogen application was higher at present.It was obviously proved that decreasing nitrogen application which did not reduce the yield significantly could improve the capability the nitrogen changing into economic yield and reduce the rice plant "luxury" nitrogen consumption.It would be good to balance the N use efficiency and seed setting rate and to enhance the economic efficiency.