在南疆生态条件下通过不同氮素水平(0、207、258.75、310.5、362.25 kg/hm2)的大田试验,研究了氮素对棉花叶片光合特性和产量的影响.结果表明,追施氮肥可以提高棉株叶片叶绿素含量,改善叶片光合性能、增加叶面积,提高中下部叶片光合速率,提高光合产物的生产能力,廷缓叶片衰老.施氮过多,棉株后期营养生长过旺,田间郁蔽,通风透光不良,影响光合作用.当施氮量在0～258.75 kg/hm2范围内,棉花产量随着施氮量增加而增加,施氮量超过258.75 kg/hm2,产量呈下降趋势.%Based on an nitrogen experiment under ecological condition in Southen Xinjiang, the effect of nitrogen fertilizer on photosynthentic characteristics and yield of cotton were investigated. The result showed that topdressing nitrogen rate could improve photosynthetic characteristics and the chlorophyll content of cotton, delay senescence of leaves and raise net photosynthesis rate; cotton leaves area and LAI were enhanced with reasonable N application, and LAI decreased rapidly in later stages with excessive N rate. Shedding rate of cotton stem leaf declined when N rate was 258.75 kg/hm2.Cotton yield increased when N rate applied was among 0 ～ 258.75 kg/hm2, and decreased until N rate applied exceed 258.75 kg/hm2.
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