施氮量和时期运筹对超级杂交稻植株氮含量与籽粒产量的影响研究

以当前长江中下游稻区具有代表性的高产超级稻品种Y两优1号为材料，采用不同施N量与施N时期分配的田间试验，研究施N对超级稻植株N含量与籽粒产量的影响，从而明确超级稻高产的穗肥N施用量和比例。结果表明：随着施N量的增加，超级稻茎叶和籽粒N含量均呈线性升高，而且施N量对生殖生长阶段茎叶N含量的影响更为显著；与总施N量相比，穗肥N对生殖生长阶段各时期茎叶N含量的影响斜率要高1.88、1.02、1.86和2.28倍，而对成熟期籽粒N含量的影响斜率要高3.59倍。分蘖盛期至抽穗期的茎叶N含量与籽粒产量呈显著线性相关，而成熟期茎叶和籽粒N均与籽粒产量表现为二次抛物线关系；通过模拟方程和不同施N比例处理的叶片外观特征均推算出超级杂交稻达到最高产量的穗肥N用量为59.0 kg/hm2，占总施肥量32.8%。对4个时期施N比例进一步分析表明，各处理籽粒产量与由方程计算的最高产量接近，10-50-25-15处理的籽粒产量要高1.7%，说明合理分配部分N作为粒肥更有利于提高超级杂交稻产量。超级杂交稻合理穗肥（和粒肥）N有利于优化成熟期茎叶和籽粒N含量，从而构建超级稻最大库容量，使其达到最高产量水平。

Effect of nitrogen application amount and stage management on nitrogen content in plant and grain yield of super hybrid rice

Two field experiments, i.e., nitrogen-fertilizer amount and ratio in different growth stages, were conducted by using current representative super hybrid rice--No1 Y Liangyou at the middle and down reach of Yangtze River. The dynamics of stem-leaf nitrogen content affected by nitrogen-fertilizer amount and fertilization stage, relationship between nitrogen application and plant nitrogen content, plant nitrogen content and grain yield were studied to understand the amount and ratio of spike nitrogen. The results showed that the nitrogen content in stem-leaf over the whole growth season, especially in generative growth stage were linearly raised as nitrogen-fertilizer amount increased; Compared with total nitrogen amount, the coefficients of spike nitrogen amount and stem-leaf nitrogen content in generative growth stage were 1.88, 1.02, 1.86 and 2.28 times higher respectively, the coefficient of spike nitrogen amount and grain nitrogen content in mature stage was 3.59 times higher. The nitrogen content in stem-leaf from active tillering stage to heading stage was significantly positive linear correlated with grain yield, but the nitrogen content in stem-leaf and grain at mature stage was secondary parabola correlated with grain yield; The spike nitrogen amount of the highest yield was 59.0 kg/hm2, accounted for 32.8% of total nitrogen application, which was figured out through simulated models and oblanceolate of leaf in different nitrogen fertilization treatment observed during experiment. The rational nitrogen ratio at the four stage, which distributed part of spike nitrogen (15%) to grain was more beneficial to high yield of super hybrid rice. Their yields were near to the highest yield which was measured from equation. The rational spike (and grain) nitrogen ratio is propitious optimize nitrogen content in stem-leaf of super hybrid rice at manure stage subsequently to build the highest storage capacity and realize the maximal yield level of super hybrid rice.