干旱盐渍土区土壤水盐运动数值模拟及调控模式

在干旱绿洲灌区,土壤盐渍化是农业生产和生态保护面临的主要危害之一,而大多盐渍化过程与灌溉水质和地下水埋深密切相关,合理确定灌区水盐调控措施是实现绿洲农业发展的必由之路。该研究基于绿洲农田试验数据,构建了田间尺度二维土壤水盐运移数值模型,并利用监测数据进行了模型校正和验证,结果表明该模型是可信的。该文以小麦作为研究对象,考虑作物需水规律和土壤盐分变化情况,制订了合理灌溉水量和灌溉制度,并以优化后的灌溉水量和灌溉制度,以不同地下水埋深作为宏观调控标准,确定了盐渍土区合理的地下水水盐调控深度。研究结果可为干旱区水资源合理利用和水盐调控提供理论基础。

Numerical simulation and control mode of soil water and salt movement in arid salinization region

In arid oases irrigation areas, soil secondary salination is one of the main problems leading to land desertification, so as to imperil the soil quality, growing of crops and agricultural production, even leading to abandonment of agricultural soils. Most salinization processes of salt accumulation in irrigated lands are largely determined by the salinity of the irrigation water and the groundwater level in the areas. So it is very crucial to control groundwater and slat for agricultural development. In this study, a two-dimensional numerical model for the soil water and salt movement was constructed, and it was calibrated and experimentally validated using data from long irrigation experiments in Yanqi basin during April 15th to December 30th in 2010 with total up to 260 days. Acceptable agreement between the model simulations and the observed data was achieved. The results show that the model is creditable. Taking wheat as an example, and considering crop's water requirement and soil salinity change, the practical irrigation program and irrigation water quantity were worked out. Based on the optimized irrigation program and irrigation water quantity, the reasonable controlled depth for groundwater and salinity regulation was determined that taking the different groundwater depths as macro-control criterion. The research can provide a theory basis for rational utilization of water resources and water-salt regulation in arid regions.