北疆土壤温度变化对滴灌棉田水盐运移规律的影响研究

以北疆常年膜下滴灌棉田为研究对象，分析棉花整个生育过程中土壤温度变化对棉田水盐运移规律的影响，并对灌溉制度进行优化调整。研究结果表明：土壤温度随着气温的升高而升高，降低而降低，气温影响作用随着土壤深度的增加而减弱，滞后时间随着深度的增加而延长；8月份之前，土壤温度自上而下呈递减分布，随着土壤温度的升高，土壤水分扩散率不断增大，土壤持水能力不断降低，造成5～60 cm处土壤含水率降低，而90～150 cm处土壤含水率增高，导致5 cm和90～150 cm处土壤盐分相对增高；8月份之后，随着土壤温度的降低，土壤温度分布发生变化，土壤水分扩散率不断减小，土壤持水能力不断增强，土壤水分蒸腾降低，渗漏减小，各层土壤含水率相对保持较高，各层土壤含盐率相对保持较低；在灌溉定额不变的条件下，在5、6月份相对减小灌水定额，7月和8月份相对减小灌水周期、增加灌水定额，8月之后相对增加灌水周期、减小灌水定额，在生育期末，通过穿插灌水，加大灌水定额，对土壤洗盐、抑盐有着明显的作用。

Study on the effects of soil temperature change to water and salt moving rule in cotton field by drip irrigation

In this paper taking the cotton field in northern Xinjiang under perennial drip irrigation below membrane as the research object, has discussed the effects of the soil temperature change to the soil water and salt moving rule in cotton field during whole growth period, also carried out the optimal adjustment for the irrigation schedule. The research results showed that: The soil temperature will be increased with the air temperature rise, reduced with the air temperature decrease. But the air temperature impacting function will be attenuated with the soil depth increasing, also the lag time will be extended with the depth increases. Before August, the soil temperature showed a decreasing distribution from top to bottom, with the increase of soil temperature, the soil water diffusivity kept a unceasing increase, the soil water-holding capacity kept a unceasing decrease, so caused the soil water content decrease at 5 to 60 cm, while the soil water content increased at 90 to 150 cm, resulted in the soil salinity was relatively higher at 5 cm and 90 to 150 cm. After August, with the decrease of the soil temperature, the distribution of soil temperature occurred change. The soil water diffusivity kept unceasing decrease and the soil water-holding capacity kept unceasing increase. The transpiration of soil moisture reduced and deep percolation decreased. The moisture content in each soil layer was kept relatively higher and the soil salinity in each soil layer was kept relatively lower. Under the condition of unchanged irrigation quota, in May and June, relatively reduce the irrigation quota, but in July and August, relatively diminish the irrigation interval and increase the irrigation quota. After August, relatively increase the irrigation interval, reduce the irrigation quota, at the end of growth period, increase the irrigation quota, which has a significant role for washing soil''s salt and suppression of soil salinity.