冬水田减量施氮对免耕直播杂交稻产量及氮肥利用率的影响

Effects of Reduced Nitrogen Application Rate on Grain Yield and Nitrogen Use Efficiency of No-tillage Direct-seeded Hybrid Rice in an All-time Logged-water Paddy Field

为探明减量施氮对冬水田免耕直播杂交稻产量和氮肥利用率的影响,为冬水田区直播杂交稻的科学施氮提供理论依据,以中熟杂交稻品种川康优6276和迟熟杂交稻品种内6优107为材料,设置3个施氮处理(N_(1),常规施氮180 kg/hm^(2);N_(2),减量施氮153 kg/hm^(2);N_(0),不施氮,对照),研究不同施氮量对免耕直播杂交稻产量、产量构成、干物质积累和氮肥利用率的影响。结果表明:冬水田区减量施氮对免耕直播杂交稻产量有显著影响。与N_(0)相比,N_(1)、N_(2)处理杂交稻产量分别提高了49.4%~51.4%、46.7%~47.7%;N_(2)处理施氮量较N_(1)处理虽减少15%,但氮肥农学利用率和氮肥偏生产力分别提高了7.3%~14.1%和13.9%~16.5%,且水稻产量无显著差异。与N_(1)相比,N_(2)处理有效穗数、颖花量分别减少8.0%~11.0%、2.8%~5.4%,但每穗粒数和结实率提高了3.2%~9.1%、1.2%~2.7%;齐穗期叶面积指数、齐穗期、齐穗后、成熟期干物质量分别减少4.6%~9.6%、3.6%~5.9%、0.5%~7.8%、4.2%~4.7%,但收获指数提高了2.7%~2.8%。因此,冬水田减施15%氮肥可实现免耕直播水稻产量和氮肥利用率的协同提高。

In order to explore the effects of reduced nitrogen application on yield and nitrogen use efficiency of no-tillage direct seeding hybrid rice in winter paddy field,and to provide theoretical basis for scientific nitrogen application of direct seeding hybrid rice in winter paddy field,Chuankangyou 6276,a mid-maturing hybrid rice variety,and NeiLiuyou 107,a late-maturing hybrid rice variety,were used as experimental materials to set up three nitrogen application treatments(N_(1),with conventional nitrogen application amount of 180 kg/hm^(2);N_(2),nitrogen application amount of 153 kg/hm^(2);N_(0),No nitrogen application control).The effects of different nitrogen application rates on yield,yield components,dry matter accumulation and nitrogen use efficiency of no-tillage direct seeding hybrid rice were studied.The results showed that reduced nitrogen application in winter paddy field had a significant effect on the yield of no-tillage direct seeding hybrid rice.Compared with N_(0),the yield of N_(1) and N_(2) no-tillage direct seeding hybrid rice increased by 49.4%-51.4% and 46.7%-47.7%,respectively.Although the nitrogen application rate of N_(2) treatment decreased by 15%compared with N_(1) treatment,nitrogen agronomic use efficiency and nitrogen partial productivity increased by 7.3%-14.1% and 13.9%-16.5%,respectively,and there was no significant difference in rice yield.Compared with N_(1),the number of effective panicles and spikelets of N_(2) no-tillage direct seeding hybrid rice decreased by 8.0%-11.0% and 2.8%-5.4%,respectively,but the number of grains per panicle and seed setting rate increased by 3.2%-9.1% and 1.2%-2.7%,respectively.The leaf area index at full heading stage,the dry matter quality at full heading stage,after heading stage and mature stage decreased by 4.6%-9.6%,3.6%-5.9%,0.5%-7.8% and 4.2%-4.7%,respectively,but the harvest index increased by 2.7%-2.8%.In summary,the synergistic improvement of no-tillage direct seeding rice yield and nitrogen use efficiency could be achieved by reducing the application of nitrogen fertilizer by 15%in winter paddy field.