银川灌区灌溉回归水质量评价

银川灌区回归水指灌溉农业土壤深层渗滤水、农田尾水、渠道渗漏水、退水及少量的工业废水和城镇生活污水，年排量２３．３亿ｍ３。我们对三条主要排水干沟回归水中２８种物质含量评价表明：属无毒有害型微咸水，采取与黄河水掺灌或轮灌适宜的灌溉制度对作物生长及土壤盐碱化无不良影响，可开发利用作灌溉用水。

Quality Evaluation of Drainage Water for Irrigation in Yinchuan Irrigation Area.

Drainage water in Yinchuan comes mainly from percolation of surface water,overflow and seepage from running over from irrigation,waste water from factories,and sewage from towns and cities.The drainage water amounts to 2.33 billion m 3 a year.The quality evaluation on 28 chemicals in the water in 3 main drainage ditches showed that the waste water was toxic free but slightly salty and might cause negative impacts on soils or crops used directly as irrigation water.The mixation of rotative irrigation of the drainage water with water from the Yellow River would not cause any damages to crops and not accelerate soil salinization and alkalization.