中文摘要：

秋浇是河套灌区一种特有的灌溉制度,对灌区农业可持续发展起到至关重要的作用.本文以河套灌区义长灌域为研究区,收集了研究区近30 a的监测资料,分析义长灌域引排水盐量变化特征及秋浇对地下水盐的影响.研究结果表明：1981—2010年研究区引排水与引排盐量变化趋势相似,引水量相对稳定,引盐量呈上升趋势;排水、排盐量变化幅度较大,增减频繁.研究区排水、排盐效果差,多年平均排水、排盐量分别占引水、引盐量的4.80%和11.06%,灌区长年处于积盐状态.秋浇占全年引排水盐量的比例较大,尤以排盐所占比例最大,多年平均秋浇排盐量占年排盐量的53.81%.秋浇对地下水位影响显著,秋浇前后地下水位相差较大,秋浇后地下水位为全年最高水位.秋浇虽具有良好的压盐效果,但不具备减少灌区积盐、改善地下水水质的效果.提高研究区排水排盐能力是改善义长灌域地下水环境的首要任务.

英文摘要：

Autumn irrigation is a unique scheme in Hetao Irrigation District,and it plays a vital role in the sustainable development of agricultural irrigation. However, autumn irrigation also has an impact on groundwater table and groundwater quality.In order to understand this impact better,Yichang Irrigation Sub-district in Inner Mongolia was studied.Both quantity and quality of irrigation water and discharged water were analyzed from monitoring data from 1981 to 2010.It was found that exported salt in discharged water accounted for 53.81% of the whole irrigation period.Groundwater table reached peak value after autumn irrigation, therefore irrigation,especially autumn irrigation,controlled dynamics of groundwater table.But there was no significant change in total dissolved solid （TDS）before and after autumn irrigation.A reasonable ratio of discharged to irrigation water and measures to improve water discharge efficiency need to be further studied.