[Responses of cotton canopy structure characteristics to drip irrigation quota in north Xinjiang, China].

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. W: 600 m·hm, W: 540 m·hm, W: 480 m·hm, W: 420 m·hm, W: 360 m·hm. The results showed that with the decrease in drip irrigation quota, LAI, LIR and CAP of cotton substantially decreased, with the difference between W and W 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 and 2677 kg·hm, respectively) presented in W. W got a 6.5% reduction of seed cotton yield compared with W, 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 m·hm 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.