关键词: 杂交籼稻, 机插稻, 减氮模式, 产量, 氮肥利用率

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