西北干旱区土壤的生态特征与变化

ECOLOGICAL FEATURES AND VARIANCE OF SOILS IN NORTHWEST ARID AREA OF CHINA

本文利用详实的资料，分析了干旱区主要土壤类型、分布及其生态意义，土壤的理化性状、养分特征以及在盐碱化、沙化和灌耕条件下的变化，并论证了这种变化在生态功能上的影响。其结果表明：①干旱土壤分布具明显空间垂直地带性及径向分布规律。极端干旱条件下的暖温带棕漠土的生态功能最差，其他土壤的生态功能排序依次为灰棕漠土＜ 灰漠土＜ 灰钙土（棕钙土）＜ 灌耕土＜ 草甸土类；②土壤生态性能在灌耕，风沙及盐碱化条件下发生显著变化，耕灌条件下使高生态性能的土壤逐渐退化而低生态性能土壤有所改善；盐碱化和风沙化的结果使土壤贫瘠化和粗质化，生态性能严重退化；干旱区平原土壤的生态特征与变化规律决定了其具有潜在荒漠化倾向。对干旱区土壤和生态特性及其变化的认识。

types,distribution,physical-chenmical status and nutrient etc. of soil and their changes in the conditions of salinization,desertization and cultivation are analysed in this paper.The results indicate that:①In arid area,soil distributions have markable vertical and longitude landscape zone,The ecological function of the warm-temperate brown desert soil is worst and that of the other soils are arranged as follows:grey brown desert soil<grey desert soil<grey calcium soil<cultivation soil<castanzem<forest-brunigra soil.②In the different conditions such as cultivation,desertization and salinization,ect.,the ecological functions of soils vary obviously. The soils with high ecological function would be degenerated, however the soils with lower ecological funtions would be improved in the cultivation condition.The desertization and salinization make the soils infertile and rough.It is basic work for rational utilization of water and land resources and protecting the ecological environment to recognize the ecological functions and their changes of soils in arid area. \ \