内蒙古农业灌区秋浇的盐分流失变化

在农业废水产生量较大的秋浇期,选取14条引水和排水渠中的灌溉引水和秋浇退水进行盐份含量及组分分析,并针对重点渠段进行了45d 的连续监测.结果发现,在各引水渠中盐分含量都较低,全盐量基本在300mg·L-1左右.排水渠中全盐量较引水渠中有大幅升高,其中第8灌域与第9灌域的排干渠中的全盐量达到 6000mg·L-1以上.水质综合分析表明,灌溉后退水都为盐碱水和重盐碱水.同时,排水渠中高含盐量是随着灌区的秋浇活动而持续发生的,并且与灌溉引水量成比例关系.研究表明,内蒙古农业灌区的秋浇活动是导致乌粱素海以及黄河中下游水中盐分含量过高的主要原因之一.

Study on salt losses in the period of fall irrigation in the agricultural irrigation area of Inner Mongolia

During the fall irrigation period, water from fourteen channels in the agricultural irrigation area was sampled to analyze the salinity and ionic components. Meanwhile, a 45-day continuous monitoring was carried out on the typical channels. The results showed that salt content kept a low level in the head race as the total salt content was about 300 mg·L-1. The total salt content in offtakes remained at quite a high level, among which those from the 8th irrigation district to the 9th irrigation district even reached 6000 mg·L-1. The high salt content came along with the irrigation activity, and was obviously related to the water volume. Based on chemical analysis, the water in the offtakes was entirely salty or heavily salty, mainly resulting from fall irrigation. And fall irrigation was the main cause of the high salt content in WuLiangSu Lake and the Yellow River as well.