干旱区生态环境知识资源中心

According to the principle of salt equilibrium in irrigation districts, the salt equilibrium of Weigan river irrigation district is analyzed with the perennial measured data. The factors affecting critical ratio of drainage to irrigation and the method determining critical ratio of drainage to irrigation are also discussed profoundly. The results show that: critical ratio of drainage to irrigation is related to the irrigation water volume, drainage water volume, salt content of irrigation water and drainage water and so on. The critical ratio of drainage to irrigation for Weigan river, Kuche county, Xinhe county, Shaya county are 9.4%, 15.1% 5.1%, 4.6%, respectively. If there is no special topography, the critical ratio of drainage to irrigation in oasis irrigation district in arid area is about 5%. It is necessary to maintain somewhat amount percolation to keep hydro-saline balance, when making irrigation schedule, implementing management of irrigation and drainage. Moreover, it is urgent to improve the drainage system in order to operate the irrigation system under the condition where actual ratio is larger than critical ratio of drainage to irrigation.