覆膜滴灌条件下土壤水盐运移规律

Soil Water and Salt Dynamic under Film Mulched Drip Irrigation

随着灌溉扩展和大规模节水灌溉的实施,新疆的土壤盐渍化表现出了新的问题和特征。通过模拟新疆当地的灌溉种植实践,研究了覆膜滴灌条件下的土壤水盐运移和集聚规律。研究表明:当下层土壤电导率高于7.5dS/m时,棉花根系向下生长缓慢,主要表现为横向扩展,并且下层土壤盐份浓度越高,根系向下层扩展的时间越迟。淡水滴灌盐土,可使上部土壤(20cm以上)逐渐脱盐;微咸水滴灌盐土,土壤表层盐份含量会有一定增加并稳定于一定数值。微咸水灌溉导致的土壤盐份浓度大幅升高不容忽视。对于低盐土壤,微咸水灌溉引入的盐分主要增加深层土壤的盐份含量;对于高盐土壤,微咸水灌溉携入的盐份主要积累于20cm处。

With the development of irrigation and large-scale water-saving irrigation, the salinization of soil in Xinjiang showed new problems and characteristics. Study on movement and accumulation of water and salt was conducted through simulation test. The results showed： when the electrical conductivity in lower soils was above 7.5 ds/m, the roots of cotton slowly extended downwards, the salt content in lower soils, the later the roots of cotton firstly extended along transverse direction. The higher expanded to lower soils. Drip irrigation with fresh water desalted the upper saline soil gradually. Brackish water irrigation increased salt content of topsoil at certain extent and the salt content of topsoil was kept at certain values. It cannot be ignored that the salt content in soil was considerably increased because of brackish water irrigation. The salt introduced by brackish water moved to deeper soil layer in low saline soil. Salt introduced by brackish water mainly accumulated at 20 cm below surface soil.