宁夏银北灌区农田排水再利用水质风险评价

Evaluation of water quality hazard of drainage reuse in Yinbei irrigation district,Ningxia

基于宁夏银北灌区三个排水干沟2000年以来的水质状况监测数据,对排水沟水质进行综合评价,开展排水灌溉再利用下的土壤盐渍化风险评价。结果表明,灌水期排水沟水质指标好于非灌水期,综合污染指数<1.0,且年际间的变化呈减少趋势;灌水期沟水呈弱碱性,属低矿化度微咸水,pH值的年内和年际变化较为稳定。农田排水再利用对土壤盐渍化具有潜在风险,排水条件和土壤透水性相对较好条件下的土壤盐渍化风险程度相对较小。

This paper analyzed the water quality of drainage water and saline-alkaline hazard of drainage reuse based on water quality data of three drainage ditches since 2000 in Yinbei irrigation diatrict,Ningxia.The results showed that every index of drainage water during the irrigation was better than that during the non-irrigation,the integrated pollution indexes were all less than 1.0.The integrated pollution indexes,which were calculated based on irrigation period,had a decreasing trend year by year.The drainage water in the ditches belongs to weak alkaline water with low mineralization during the irrigation,and the annual and inter-annual variations of pH were basically steady.The drainage reuse might bring the potential saline-alkaline hazard for soil.In the regions where there are good drainage and ventilated soil,the saline-alkaline hazard was smaller.