阿拉尔垦区土壤盐渍化治理与土地持续利用

塔里木河上游的阿拉尔垦区在开垦前主要发育着不同盐渍化程度的土壤。经过３０多年的改造，垦区土壤盐渍化治理已取得了一些进展，但也还存在许多问题，解决好这些问题将是今后土壤盐渍化治理与实现土地持续利用的重点。

THE CONTROL OF SALINISATION AND LAND SUSTAINABLE UTILIZATION IN ARAL IRRIGATED AREA,TARIM RIVER BASIN

Aral irrigated area in the upper reaches of the Tarim river was set up in the later 1950s, its soil development existed different degree of salinisation be fore reclamation. Some progresses have been made through more than 30 years efforts in the control of salinisation. There have been a series of changes in the drainage ways in Aral irrigated area in recent several decades.The drainage systems were developed from no drainage to arterial drainage channels, and then to complete connection between arterial, secondary, and tertiary drainage channels. The lengthof external drainage channels to tertiary ones was up to 1 845 km in 1994. In addition, the maintenance method of drainage systems was improved, mechanical dredge has replaced artificial dredge. Irrigation channels anti-seepage has also been enhanced. Anti-seepage measure was carried out not only on arterial channels, but also on secondary and tertlary channels. The length of anti-seepage channels from arterial to tertiary ones reached 686 km in 1994.However, from the viewpoint of land sustainable utilization, its control of salinisation stillexists lots of problems. First, drainage from farm lands causes the water quality salinisation of the Tarim River. In Aral hydrometric station in 1991, degree of mineralization of river water was more than 1 g/L in all the months and more than 5 g/L in April, September, Novemher.Second, because the unstable desalinisation is the main type in the irrigated area, soils salinisation still poses a threat to the development of agricultural production. Third, unreasonable crop structure in the past several years has changed the controlling model of salinlsation. At present,the cultivated area of cotton has made up more than 70% of that of croplands. If a farm only cultivates one kind of crops on a large scale, it is unfavourable for prevention of plant disease and insect pests, and crop rotation. Fourth, water conveyance efficiency is low, there is almost no anti-seepage measure on feeder. In order to carry out land sustainable utilizaton, some countermeasures should been worked out as follows: (1) exploring other drainage outlets and alleviating pollution to the river water;(2) strengthening savlng water engineering construction and raising water conveyance efficiency; (3) setting up the net of water and salt dynamic monitoring, and controlling development of salinisation; (4) adjusting crop structure and increasing the cultivated area of other crops apart from cotton.