【目的】阐明氮肥减施关键时期和适宜减施量对不同穗型迟熟中粳水稻的产量及氮肥吸收利用的影响。【方法】以大穗型品种(丰粳3227)、中穗型品种(淮稻5号)和小穗型品种(扬辐粳8号)为材料，设置12种氮肥处理模式，即不施氮(0N)、当地常规施氮(CN，300 kg/hm²)、基肥减总氮10%与20%(BN₁₀、BN₂₀)、分蘖肥减总氮10%与20%(TN₁₀、TN₂₀)、促花肥减总氮10%与20%(SPN₁₀、SPN₂₀)、保花肥减总氮10%与20%(SNN₁₀、SNN₂₀)和均衡减氮10%与20%(AN₁₀、AN₂₀)。【结果】减氮处理下大穗型品种丰粳3227、中穗型品种淮稻5号和小穗型品种扬辐粳8号产量整体降幅分别为6.17%、7.67%和7.81%，尤以减氮20%降幅最大，其中，丰粳3227、淮稻5号和扬辐粳8号在SPN₁₀、AN₁₀和SSN₁₀处理下产量降幅分别为0.17%、0.79%和0.23%，与CN相比略有下降但差异不显著。在相同减氮模式下，产量降幅最高的为小穗型品种，其次是中穗型品种，最后则为大穗型品种。减氮降低了单位面积有效穗数和每穗粒数，但提高了结实率。减氮处理后有效穗数对大穗型品种丰粳3227的产量促进作用最大，每穗粒数则对中穗型品种淮稻5号和小穗型品种扬辐粳8号产量的贡献最大。减氮处理降低了氮素转运量和穗部氮素积累量，提高了氮素吸收利用率和氮肥偏生产力。减氮模式下大穗型品种丰粳3227、中穗型品种淮稻5号、小穗型品种扬辐粳8号分别在SPN₁₀、AN₁₀、SSN₁₀处理下的氮肥利用效率指标总体优于其他处理。【结论】大穗型品种在促花肥适量减氮、小穗型品种在保花肥适量减氮及中穗型品种均衡减氮处理下达到减氮不减产并提高氮肥吸收利用率。适量减氮能够调节不同穗型水稻群体的生长特性以实现产量稳定，但过量减氮使水稻群体自身的产量调节效应变弱。

【Objective】The purpose of this study is to clarify the effects of the key period of reduced nitrogen application and appropriate reduced application rate on the yield and nitrogen absorption and utilization efficiency of late-maturing mid-japonica rice with different panicle types. 【Method】Using large panicle cultivar (Fengjing 3227, FJ3227), medium panicle cultivar (Huidao 5, HD5) and small panicle cultivar (Yangfujing 8, YFJ8) as materials, 12 nitrogen fertilizer treatments were designed, namely zero nitrogen application (0N), local conventional nitrogen application (CN, no nitrogen reduction, 300 kg/hm²), basal nitrogen fertilizer reduction by 10% and 20% (BN₁₀, BN₂₀), nitrogen reduction by 10% and 20% in tillering fertilizer(TN₁₀, TN₂₀), nitrogen reduction by 10% and 20% in flower-promoting fertilizer (SPN₁₀, SPN₂₀), nitrogen reduction by 10% and 20% in flower-preserving fertilizer (SNN₁₀, SNN₂₀) and average nitrogen reduction of 10% and 20% (AN₁₀, AN₂₀), to study the effects of different nitrogen reduction modes on yield and nitrogen absorption and utilization of medium-maturing japonica rice varieties differed in panicle type. 【Result】Under reduced nitrogen treatment, the overall yield of FJ3227, HD5 and YFJ8 decreased by 6.17%, 7.67% and 7.81%, respectively, with greater decrease in 20% nitrogen reduction. For FJ3227, HD5 and YFJ8 under the treatment of SPN₁₀, AN₁₀ and SSN₁₀, the yield dropped by 0.17%, 0.79% and 0.23%, insignificantly lower than CN. Under the same nitrogen reduction model, the highest yield decline was observed in small panicle variety, followed by medium panicle type variety, and large panicle type variety. Nitrogen reduction reduced the number of effective panicles and the number of grains per panicle, but increased the seed setting rate and 1000-grain weight. As a result of nitrogen reduction, the number of effective panicles had the greatest promotion effect on the yield of the large panicle cultivar FJ3227, while the number of grains per panicle contributed the most to the yield of the medium panicle cultivar HD5 and the small panicle cultivar YFJ8. Nitrogen reduction treatment reduced the amount of nitrogen transportation and the amount of nitrogen accumulation. And the nitrogen reduction treatments reduced the nitrogen uptake at the jointing stage, heading stage and maturity stage. There were significant differences between treatments and varieties. Nitrogen reduction improved nitrogen fertilizer absorption and utilization and nitrogen partial productivity. Under the nitrogen reduction mode, the large panicle cultivar FJ3227, the medium panicle cultivar HD5, and the small panicle cultivar YFJ8 under the treatments of SPN₁₀, AN₁₀, and SSN₁₀ have higher nitrogen use efficiency. 【Conclusion】The large panicle variety can reduce nitrogen by appropriate amount of fertilizer for promoting flowers, the small panicle variety can reduce nitrogen by medium amount of flower-preserving fertilizer, and the medium panicle variety can achieve nitrogen reduction without reducing yield and improve nitrogen absorption and utilization. Medium nitrogen reduction can adjust the growth characteristics of different panicle rice populations to achieve stable yield. Yet the excessive nitrogen reduction weakens its yield regulation capacity.