覆盖措施对咸水结冰灌溉后土壤水盐动态和棉花生产的影响

对咸水结冰灌溉融冰后不同防止返盐措施处理的土壤水盐动态以及棉花的出苗、生长特征和产量进行了研究。结果表明,不同的覆盖措施对抑制土壤表层水分蒸发的效果有显著差异,3月和4月份表层土壤含水量影响5月份的含盐量,而5月份表层土壤的含盐量直接决定棉花出苗率。地膜覆盖和保留前茬旧膜的处理保墒抑盐效果最好,棉花出苗率和产量也最高;秸秆覆盖也有一定的抑盐效果;而翻耕和中耕对土壤保墒抑盐的作用较差;液态膜处理的抑盐效果最差,棉花的出苗率和产量最低。可见保留前茬旧膜是简便有效的保墒抑盐途径。

Effects of Different Salt Control Measures after Saline Water Freezing Irrigation to Soil Water,Salt Dynamics,Cotton Emergence and Yield

Saline water freezing irrigation in winter is an effective way to plant cotton in the heavy saline land of northern China, where there is little fresh water to cultivate crops. After saline water ice melts in spring, mulching is necessary to maintain a low salt content in the surface soil. In this study we investigated the effects of different field soil salt control measures on the emergence rate of cotton seeds, growth characteristics and cotton yield. The results indicated that, in spring, film mulching and old film mulching could effectively reduce evaporation and salt accumulation at the soil surface. Straw mulching was the next most effective treatment, followed by liquid film, while tillage and intertillage were the least effective treatments. Emergence of cotton seeds was dependent on the salt content of the topsoil layer in May, which was closely related to soil moisture in March and April. Cotton yields were positively correlated with seed emergence rates. Cotton yields of fields mulched with plastic film and old film were the highest at 3226.13 and 3142.14 kg·hm－2, respectively, while cotton yields of fields mulched with straw (2029.81 kg·hm^－2) and liquid film(782.79 kg·hm^－2) were much lower. According to the cotton seed emergence rates and yields, this study found that old film mulching after the saline ice melted could effectively control salt accumulation and was also a time and labor saving measure.