We investigated the effects of different drip irrigation quotas on leaf area index (LAI), diffuse non-interceptance (DIFN), light interception rate (LIR), canopy apparent photosynthetic rate (CAP), and cotton yield of Xinluzao 45 in field of north Xinjiang. There were five drip irrigation treatments, i.e. W1: 600 m3·hm-2, W2: 540 m3·hm-2, W3: 480 m3·hm-2, W4: 420 m3·hm-2, W5: 360 m3·hm-2. The results showed that with the decrease in drip irrigation quota, LAI, LIR and CAP of cotton substantially decreased, with the difference between W1 and W2 being not statistically significant from the full squaring to boll opening stage. Moreover, DIFN was enhanced with the reduction in drip irrigation quota. Highest seed and lint yield (6549 kg·hm-2 and 2677 kg·hm-2, respectively) presented in W1. W2 got a 6.5% reduction of seed cotton yield compared with W1, but the irrigation water use efficiency was enhanced by 3.9%. LAI, LIR and CAP were positively correlated with seed cotton yield from full flowering stage to full boll stage. Therefore, drip irrigation quota at 540 m3·hm-2 could increase irrigation water use efficiency, maintain higher leaf area index, increase diffuse non-interceptance, and ensure light interception rate from full flowering stage to full boll stage, which could enhance canopy apparent photosynthetic rate and water use efficiency without sacrificing yield.
在新疆北部地区自然生态条件下,采用棉花品种‘新陆早45号’为试验材料,设置5种滴灌定额处理(W1:600 m3·hm-2,W2:540 m3·hm-2,W3:480 m3·hm-2,W4:420 m3·hm-2,W5:360 m3·hm-2),研究了棉花叶面积指数、冠层开度、群体光吸收率、群体光合速率和产量对不同滴灌定额的响应.结果表明: 随着滴灌定额减少,棉花叶面积指数、群体光吸收率、群体光合速率均呈现降低趋势,其中W1与W2处理间的上述参数在盛蕾期至吐絮期均无显著差异;冠层开度则随滴灌定额减少呈增加的趋势.籽棉产量和皮棉产量均以W1处理最高,分别为6549和2677 kg·hm-2;W2处理籽棉产量仅比W1处理低6.5%,灌溉水利用效率较W1处理高3.9%.相关分析表明,盛花期至盛铃期叶面积指数、群体光吸收率和群体光合速率均与籽棉产量呈显著或极显著正相关.因此,控制滴灌定额在540 m3·hm-2有利于棉花在盛花至盛铃期保持较高的叶面积指数、增加冠层开度、保证光吸收率,进而增强群体光合速率,在不显著降低产量前提下提高灌溉水利用效率.
Keywords: canopy apparent photosynthetic rate; canopy structure characteristic; cotton; drip irrigation quota; yield.