中国西部地区的盐渍土及其改良利用

Salinized Soils and Their Improvement and Utilization in West China

在中国西部大开发中 ,改良和利用盐渍土是生态环境建设重要的一个方面。本文就此论述了中国西部盐渍土的分类、分布规律和分布状况 ;盐渍土的形成过程和形成原因 ;盐渍土的危害和对经济发展的影响 ,提出了盐渍土改良利用的对策和措施。

Salinized soils in west China are mianly distributed in Xingjiang, Gansu, Qinghai, Ningxia, Inner Mongolia, and Shaanxi provinces and autonomous regions. In these regions the climate is arid, precipitation is less, and evaporation is violent. Moreover, the salinized soils are characterized by extensive distribution, strong salt accumulation, and complicated salt composition because most of these regions belong to the inland arid areas and there is no outer discharge conditions for salts. The total area of the various salinized soils in west China is as large as 33.9495 million hm 2, and accupies 69.03% of the total in the whole country. Under the irrational utilization of water and land resources, secondary salinization of the cultivated land is also serious, its area can occupy 20%～40% and 13.93% of the area of the irrigated cultivated land and the total cultivated land respectively. The secondary salinized land is the main low-yield land and can make the yield of crops drop by 20%～40%. The harmful physical-chemical properties of the salinized soils bring about a serious harmfulness to construction of roads and engineerings. Therefore, in the great development of west China, it is an important foundational construction to improve and utilize the salinized soils by taking the measures of irrigating rationally, enhancing drainage, leveling land, increasing soil fertility, etc., and by taking watersheds as the units to plan comprehensively, lay equal stress on prevention and improvement in a synthetical way.