地下水位与灌溉定额对棉花土壤水分的动态影响模拟

地下水埋深对土壤水势分布及土壤次生盐碱化具有重要影响.以新疆孔雀河流域为例,利用HYDRUS-2D软件对不同地下水位与灌溉定额下的棉花膜下滴灌土壤体积含水率的动态变化进行了模拟.结果表明:当地下水埋深为1.5 m时,地下水对土壤水的顶托作用较强,灌溉定额为3 300 m³/hm²时可使棉花生育期不受水分胁迫;当地下水埋深为2.0 m时,地下水对土壤水的补给能力下降,灌溉调控的作用逐渐加强,灌溉定额为3 900 m³/hm²时属轻度胁迫,对产量影响较小,而灌溉定额为4 500 m³/hm²时,基本不受胁迫,对产量影响极小;当地下水埋深大于2.5 m时,地下水对土壤水的补给作用进一步弱化,灌溉定额为4 500 m³/hm²时属于中度胁迫,会造成一定程度减产.研究结果为指导当地地下水资源开发利用及棉花种植业发展提供了重要参考.

Dynamic simulation of groundwater level and irrigation quota effects on cotton soil water content

Groundwater level can influence soil water potential distribution and soil secondary salinization significantly. In the paper, the dynamic change in soil water content under film drip irrigation is simulated at different groundwater levels and irrigation quotas by using HYDRUS-2D software for cotton in Xinjiang Peacock River Basin. The results show that the cotton growth remains unaffected by water stress at 3 300 m³/hm² irrigation quota when the groundwater level is 1.5 m below because the backwater effect of the groundwater on soil water is stronger. When the groundwater level is 2.0 m below, the soil water supplying capacity of the groundwater is decreased; consequently, the regulation effect of irrigation becomes dominated gradually. At 3 900 m³/hm² irrigation quota, the water stress is mild, having a little effect on cotton yield, at 4 500 m³/hm² quota, however, there is no water stress basically, and the yield is little influenced. When the groundwater level is 2.5 m below, the soil water supplying capacity is weakened further. Even though the irrigation quota is as high as 4 500 m³/hm², the water stress is moderate, and will cause a certain degree reduction in the yield. This study provides an important reference of guide for groundwater resources utilization and cotton planting development in the river basin.