通过两年田间试验，探讨了不同氮肥施用水平对春玉米光合特性、产量及其构成的影响。试验设5个处理，分别为不施氮（N1），70%推荐施氮量（70%Opt, N2），推荐施氮（Opt, N3），130%推荐施氮量（130%Opt, N4），高量施氮（N5）。结果表明，合理的增施氮肥可以显著提高玉米籽粒产量。与不施氮相比较，施氮后株高增幅平均增幅8.5 %；茎粗平均增幅8.5 %，同时期的生物量增幅达16.8 % ~ 29.1 %。N3处理下，即氮肥用量为210 kg/hm2时，叶面积指数和叶片SPAD值在处理间均最高。施氮显著提高了花后叶片净光合速率，但施氮量和叶片净光合速率之间并不呈正比，当施氮量增加到330 kg/hm2后，叶片净光合速率降低。相关性分析表明产量、叶面积指数、SPAD值、净光合速率、气孔导度、蒸腾速率间均呈正相关。可见，在本试验条件下，氮肥用量为210 kg/hm2时，并配合合理的氮肥施用比例，可改善灌浆期中前期干物质积累速率及积累量，保持较高的叶片生理活性，提高光合效能，可获得较高的产量和生物量。
英文摘要:
Through two years of field experiment, the effects of different nitrogen fertilization application levels on photosynthetic characteristic, yield and its composition of spring maize were discussed. The five treatments in the experimental design were no nitrogen(N1), 70% recommended amount of nitrogen(70%Opt, N2), recommended amount of nitrogen(Opt, N3), 130% recommended amount nitrogen(130%Opt, N4), high amount of nitrogen(N5). The results showed that the rational application of nitrogen fertilizer could increase grain yield significantly. Compared with the non-nitrogen application, the average growth rate of the plant height was 8.5 %. The average growth rate of the stem diameter was 8.5 %, and the growth rate of dry matter accumulation was 16.8 % ~ 29.1 %. Under N3 treatment, when the amount of nitrogen fertilizer was 210 kg/hm2, LAI and the SPAD were the highest among the treatments. The net photosynthetic rate of the leaves was significantly increased, but there was no positive ratio between the amount of nitrogen and the net photosynthetic rate of the leaves. When the amount of nitrogen was increased to 330 kg/hm2, the net photosynthetic rate of the leaves decreased. Correlation analysis showed positive correlation between yield, LAI, SPAD, net photosynthetic rate, stomatal conductance and transpiration rate. Under this experimental condition, the nitrogen application of 210 kg/hm2, and apply proportion of nitrogen fertilization reasonably. It can be improved dry matter accumulation rate and amount through the early and middle of milk stage, maintaining high leaf physiological activity, improving photosynthetic efficiency. Higher biomass and yield can be obtained from maize.
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