Abstract: Chuanyou 9527（V1），Yliangyou 900（V2） and Zhunliangyou 527（V3） were used as experimental materials，and six treatments including no nitrogen fertilizer（T1），the local farmers customary nitrogen application pattern（T2，CK），postponing nitrogen application with 20% reduction of nitrogen fertilizer（T3），combined application of organic and inorganic fertilizers and postponing nitrogen application with 20% reduction of nitrogen fertilizer（T4），increasing density and postponing nitrogen application with 20% reduction of nitrogen fertilizer（T5），combined application of controlled⁃release fertilizer and urea with 20% reduction of nitrogen fertilizer（T6），were set up to investigate the effects of different nitrogen fertilizer reduction patterns on panicle bearing tiller rate，leaf area index，dry matter accumulation，yield，yield components and nitrogen use efficiency of machine transplanted indica hybrid rice in the Karst area of Guizhou Province，so as to provide technical support for high yield and high efficiency cultivation of machine transplanted indica hybrid rice in Karst area of Guizhou Province.The results showed that the yield of T6 treatment was equivalent to that of T2 treatment；the yields of T5，T4 and T3 treatments increased compared with T2 treatment，the yields of V1，V2，V3 of T5 and T4 treatments significantly increased by 12.9%，23.7%，23.8% and 12.3%，14.1%，13.8%，respectively，and the yields of V1，V2 and V3 of T3 treatment increased by 7.8%，14.1%，7.6%，the yield increase of T5，T4 and T3 treatments was mainly due to the increase of leaf area index，dry matter accumulation，panicle bearing tiller rate and effective panicle number in the later stage.Nitrogen agronomic efficiency，nitrogen partial productivity，nitrogen absorption efficiency and nitrogen recovery efficiency of T5，T4，T3 and T6 treatments were generally significantly higher than those of T2 treatment. The overall performance of nitrogen agronomic efficiency and nitrogen partial productivity was T5>T4>T3>T6>T2，and the overall performance of nitrogen absorption efficiency and nitrogen recovery efficiency was T4>T5>T3>T6>T2.In conclusion，under the condition of 20% reduction of nitrogen fertilizer，T5，T4 and T3 treatments can achieve the effect of increasing production and efficiency，T5 treatment is the best，and T4 treatment is the second.

Key words: Indica hybrid rice, Machine transplanted rice, Nitrogen fertilizer reduction pattern, Yield, Nitrogen use efficiency

摘要： 以川优9527（V1）、Y两优900（V2）、准两优527（V3）为试验材料，设置不施氮（T1）、当地农民习惯施氮（T2）、氮肥后移减氮20%（T3）、有机无机肥配施与氮肥后移减氮20%（T4）、增密与氮肥后移减氮20%（T5）、控释肥尿素配施减氮20%（T6）6个处理，研究不同减氮模式对贵州省喀斯特地区机插杂交籼稻成穗率、叶面积指数、干物质积累量、产量及其构成因素和氮肥利用率的影响，以期为喀斯特地区机插杂交籼稻高产高效栽培提供理论依据和技术支撑。结果表明，与T2处理相比，T6处理产量与之相当；T5、T4、T3 处理产量提高，V1、V2、V3 中T5 和T4 处理分别显著提高12.9%、23.7%、23.8% 和12.3%、14.1%、13.8%，T3处理分别提高7.8%、14.1%、7.6%，T5、T4、T3处理产量提高主要归因于后期叶面积指数、干物质积累量、成穗率和有效穗数提高。与T2处理相比，T5、T4、T3、T6处理的氮肥农学利用率、氮肥偏生产力、氮肥吸收利用率、氮肥回收利用率总体上均显著提高，氮肥农学利用率和氮肥偏生产力总体均表现为T5>T4>T3>T6>T2，氮肥吸收利用率和氮肥回收利用率总体均表现为T4>T5>T3>T6>T2。综上，减氮20%条件下，T5、T4、T3处理均能达到增产增效的效果，以T5处理最优，T4处理次之。

关键词: 杂交籼稻, 机插稻, 减氮模式, 产量, 氮肥利用率