花铃期不同灌溉处理对棉花光合特性和产量的影响

Effects of different irrigation treatments at flowering and boll setting stage on photosynthetic characteristics and yield of cotton

【目的】揭示花铃期不同灌水下限对棉花叶片光合特征参数及产量的影响,为新疆北疆植棉区灌溉制度的优化提供参考。【方法】2023年在新疆昌吉开展大田试验,以中棉所125为供试品种,在花铃期设置3种灌水下限,分别为55%(T1)、60%(T2)和70%(T3)田间持水量,以当地常规的滴灌模式作为对照(CK),分析不同处理对花铃期土壤含水率、棉花叶片光合特性及产量性状的影响,并探究了光合指标与叶面温度和气象因子之间的相关关系和回归关系。【结果】花铃期T3处理的0~60 cm土层土壤含水率维持在相对较高且稳定的范围(18.5%~21.6%)。花铃前期(7月11日),T3处理的净光合速率日平均值最大,呈升-降-升-降的日变化趋势。相关分析表明,净光合速率、蒸腾速率均与0~60 cm土层土壤含水率、叶面温度、太阳辐射强度和环境温度呈显著正相关关系。T3处理的籽棉产量和灌溉水利用效率最高,分别较CK显著提高26.46%和71.43%。基于秩和比法的多目标综合评价表明,T3处理的综合效果最优。【结论】在水资源短缺的北疆膜下滴灌棉田,花铃期灌水下限、上限分别设置为70%、90%田间持水量可以实现节水且高产。

[Objective]This study aims to reveal the effects of different irrigation treatments at the flowering and boll setting stage on the photosynthetic characteristics and yield of cotton,and to provide a reference for the optimization of irrigation system in cotton planting areas of northern Xinjiang.[Methods]A field experiment was conducted in Changji,Xinjiang in 2023,with CCRI 125 as the test variety.Three lower limits of irrigation were set at the flowering and boll setting stage,which were 55%field capacity(T1),60%field capacity(T2),and 70%field capacity(T3),respectively.The local conventional drip irrigation mode was used as the control(CK).The effects of different treatments on the soil moisture content,photosynthetic characteristics,and yield traits of cotton during the flowering and boll setting stage were analyzed.And the correlation and regression relationships between the photosynthetic index,foliar temperature,and the meteorological factors were also explored.[Results]The soil moisture content of 0-60 cm soil layer of T3 treatment was maintained in a relatively high and stable range(18.5%-21.6%)during the flowering and boll setting period.During the early flowering and boll setting period(11 July),the daily average of net photosynthesis rate of T3 treatment was the highest,showing a daily trend of increasing-decreasing-ascending-decreasing.Correlation analyses showed that net photosynthetic rate and transpiration rate were positively correlated with 0-60 cm soil moisture content,foliar temperature,solar radiation intensity,and ambient temperature.Seed cotton yield and irrigation water use efficiency were the highest under T3 treatment,which were significantly increased by 26.46%and 71.43%,respectively,compared with that of CK.The multi-objective evaluation based on the rank-sum ratio method showed that T3 treatment had the best overall effect.[Conclusion]In the northern Xinjiang where water resources are scarce,the lower and upper limits of irrigation at the flowering and boll setting stage setting at 70%and 90%field capacity,respectively,is a reasonable water-saving and high-yield irrigation mode for cotton fields under the drip irrigation with plastic-film mulching.