晒田强度和穗肥运筹对三角形强化栽培水稻光合生产力和氮素利用的影响

以杂交中稻组合II优498为材料，在三角形强化栽培(TSRI)条件下，研究3种晒田强度(0~20 cm土壤相对含水量为80%±5%、60%±5%和40%±5%，分别记为W₁、W₂和W₃)和3种穗肥运筹(晒田复水后第1、8和15天施用第1次氮素穗肥，分别记为S₁、S₂和S₃)对灌浆结实期水稻光合生产和氮素利用的影响。结果表明，晒田程度和穗肥运筹对水稻光合生产、干物质积累、氮素积累、转运和利用和产量的影响存在显著互作效应，且晒田影响最为显著，氮素穗肥运筹次之。轻度晒田(W₁)复水后第1天施用第1次氮素穗肥会降低抽穗后15 d和30 d的群体光合和有效穗数，推迟至复水后第8天或第15天施用第1次氮素穗肥可以提高抽穗后15 d和30 d的群体光合、收获指数和氮素稻谷生产效率；中度和重度晒田(W₂和W₃)复水后第1天和第8天施用第1次氮素穗肥可以提高孕穗期和齐穗期剑叶P_n和抽穗后15 d和30 d的群体光合、干物质积累、籽粒产量及构成指标、稻株氮素积累与利用。经过分析比较得出，TSRI模式下W₂S₁为晒田强度和穗肥运筹的最优组合，产量达到10.96 t ha^-1。

Effects of Different Paddy Field Drainage Degrees and Panicle Nitrogen Fertilizer Managements on Photosynthetic Productivity and Nitrogen Utilization of Rice under Triangle-Planted System of Rice Intensification

The effects of different paddy field drainage degrees including three soil water content levels (0–20 cm soil relative water content was controlled at 80%±5%, 60%±5%, and 40%±5%, expressed by W₁, W₂, and W₃ respectively) and three panicle nitrogen fertilizer managements (the first panicle nitrogen fertilizer was applied on the 1st, 8th, and 15th days after rewatering, expressed by S₁, S₂, and S₃,respectively) on photosynthetic productivity during filling stage and nitrogen utilization of rice were investigated using medium hybrid rice II you 498 under triangle-planted system of rice intensification (TSRI). The results showed that there was an obvious interaction to photosynthetic productivity, dry matter accumulation and nitrogen uptake, translocation and utilization between paddy field drainage degree and panicle nitrogen fertilizer management. Paddy field drainage had the most significant effect compared with panicle nitrogen fertilizer management. Canopy apparent photosynthetic rate at 15 days and 30 days and effective panicle numberwere decreased, under the treatment of applying the first panicle nitrogen fertilizer on the 1st day after rewatering, and canopy apparent photosynthetic rate at 15 days and 30 days after heading, harvest index and N production efficiency were increased under the treatment of applying the first panicle nitrogen fertilizer on the 8th or 15th day after rewatering in lower paddy field drainage condition (W₁). The treatment with higher paddy field drainage condition (W₂, W₃) applying the first panicle nitrogen fertilizer on the 1st and 8th days after rewatering was favorable to improve flag leaf photosynthetic rate at booting and full heading stages, canopy apparent photosynthetic rate at 15 days and 30 days after heading, dry matter accumulation, grain yield and its components, and nitrogen accumulation and utilization. From the comprehensive analysis and comparison, W₂S₁ is the optimum combination for moderate paddy field drainage degree and panicle nitrogen fertilizer management under the TSRI, and its grain yield reached 10.96 t ha^-1.