Water and Salt Balance and Salt Movement in Weigan River Irrigation District

Base on the field investigation and measured data, the water and salt balance as well as salt movement are analyzed in Weigan river irrigation district, located in the south part of Tianshan mountain. The results show that the ratio of irrigation to is about 13% and the water consumption of cultivated land and forest land occupies 67% of the total consumption in resent years; the salt in the soil of the arable land has been changed from the accumulation to the state. The discharged salt is 1.8 times of the imported salt, which effectively prevents the soil salinity; one third of the import salt in the irrigation water drains to the Tarim River and others discharges to the lake or the bottomland inside or outside of the irrigation district. The drainage ——the method to discharge the surplus irrigation water and the groundwater with high salt content to the bottomland inside irrigation district, can decrease the discharged salt to the Tarim River and improve its water quality at the same time. The research result shows that the rational proportion between the salt accumulation land of the dry and the arable land is 1:3, which not only cut down the water with high salt content permeating the ground, but also protect the circumstance of the Tarim River. In addition, the ways to deal with the situation for improving the efficiency of irrigation water and preventing secondary salinity of the soil are pointed out.