膜下滴灌条件下不同矿化度水对土壤水盐动态及棉花产量的影响

塔里木盆地分布着相当大面积矿化度在3~5 g/L之间的浅层地下咸水,有很大的开发利用潜力。通过微区测坑试验,采用膜下滴灌技术,用不同矿化度的咸水灌溉棉花,探求其对土壤水盐动态和棉花产量的影响。研究表明:(1)土壤盐分和水分二者的动态变化是紧密相关的,其中,土壤盐分动态变化主要受大气和灌溉水的影响,土壤水分的动态变化主要受棉花生长阶段和灌溉水的影响;(2)咸水膜下滴灌与淡水膜下滴灌同样具有淋洗和压盐效果;(3)通过棉花产量分析发现:与采用淡水灌溉相比,咸水灌溉对产量,单株铃数和单铃重具有一定的影响,对衣分没有影响;(4)当灌溉水矿化度大于3.24 g/L时,不利于塔里木盆地进行农业生产。

Effects of irrigation with saline water on soil water-salt transport features and cotton yield

As freshwater is becoming increasingly short, it is impending to seek other substitute water resources for agriculture. Some saline groundwater with degree of mineralization (DOM) at 3 g/L to5 g/L in shallow underground lay er was largely distributed at some regions in Tarim Basin, and the groundwater may be a great potential source for agriculture. However, it is a great challenge about using saline water safely and effectively under the special climate and envi-ronment of Tarim Basin area. Based on the experiment of mini-plot and drip imigation under film, we irrigated cotton in different plots with water of different degree of mineralization, so as to find out dynamic changes of soil salt-water and cotton yield. The results showed that: (1) The dynamic variation of soil salt is remarkably related to that of soil water. Moreover, the dynamic variation of soil salt is mainly influenced by climate and irrigation, and the dynamic variation of soil water is mainly influenced by growth stage of cotton and irrigation; (2) Drip irrigation under flm with saline water has the same leaching effect as that of fresh water; (3) Compared with fresh water, irrigation with saline water has nega-tive effect on cotton yield, cotton boll number and boll weight, but no influence on lint percentage; (4) Water beyond degree of mineralization 3.24 g/L, is not fit for agriculture in Tarim Basin area.