施氮量对滴灌超高产春玉米光合特性、产量及氮肥利用效率的影响

在田间研究拔节期后5种施氮量处理对春玉米KWS2564吐丝后群体叶面积指数垂直分布、光合势、光合速率(穗位上第3片叶、穗位叶、穗位下第3片叶)、干物质积累、产量和氮肥利用效率的影响,揭示施氮量对滴灌超高产春玉米光合特性及氮肥利用效率的影响规律。结果表明,增施氮肥,主要增大棒3叶以下、棒3叶的叶面积指数,明显延缓吐丝后棒3叶以下叶片衰老,增加群体总光合势;增加吐丝后穗位上第3片叶、穗位叶、穗位下第3片叶的光合速率和气孔导度;增加干物质积累量和产量,降低氮肥利用效率和氮肥偏生产力。施氮量超过300 kg/hm2以上再增加施氮量,叶面积指数、光合速率、干物质和产量的增幅降低,降低氮肥农学利用效率和氮肥偏生产力。适宜施氮量为300 kg/hm2左右,可获得17 002.6 kg/hm2产量,其吐丝期叶面积指数为6.62,总光合势为423.6 m2/(d·m2),氮肥农学利用效率为13.8 kg/kg。

Effects of Nitrogen Application on Photosynthetic Characteristics, Yield and Nitrogen Use Efficiency in Drip Irrigation of Super High-yield Spring Maize

In order to reveal the law of nitrogen application on photosynthetic characteristics and nitrogen agro- nomic efficiency in drip irrigation of super high-yield spring maize, the experiments of different nitrogenapplied af- ter jointing stage were carried out in the field about vertical distribution, photosynthetic rate, photosynthetic rate and leaf area index(the third above ear leaf, ear leaf, the third below ear leaf) and dry matter accumulation of spring maize KWS2564. The results showed that, increasing nitrogen application, mainly increase the leaf area index of the three-ear-leaves and below, obviously delay leaf-senescence of the bottom leaf and increase the total population photosynthetic potentials after sinning; increase the photosynthetic rate and stomata conductance of the ear leaf and the third leaf above(below) ear, also could increase the dry matter accumulation and yield, reduce the nitrogen agro- nomic efficiency and nitrogen partial factor productivity. When the nitrogen application rate was about 300 kg/ha, the yield also could obtain 17 002.6 kg/ha, while achieve a leaf area index of 6.62 and total photosynthetic potential of 423.6 m²/(d·m²), nitrogen agronomic efficiency of 13.8 kg/kg in the silking stage.