为了了解呼伦贝尔沙质草地沙漠化过程中土壤理化特性的变化规律,于2009年在呼伦贝尔沙地的陈巴尔虎旗设置祥地,调查分析了不同类型沙漠化草地土壤理化特性的差异和变化特征,探讨了土壤理化特性沙漠化演变规律和机制,得到如下结果,1)随着沙漠化的发展,草地土壤细颗粒(黏粉粒)含量明显下降,沙粒含量明显增加,土壤质地发生粗化,其中以中度和严重沙漠化阶段土壤粘粉粒损失最为严重；2)沙漠化过程中,土壤容重和土壤温度变化不显著,土壤紧实度显著下降,土壤含水量略有增加；3)土壤有机碳和土壤氮、磷含量明显下降,同时土壤C/N大幅度下降,表层土壤pH明显下降；4)土壤有机碳和养分含量的变化与土壤黏粉粒含量,土壤硬度的变化与土壤黏粉粒和有机质含量均呈显著正相关,土壤容重、土壤温度和土壤含水量的变化与土壤机械组成的相关性均未达到显著水平；5)沙漠化过程中,土壤黏粉粒的损失是导致土壤粗化,致使土壤紧实度、土壤有机碳和养分含量下降的主要原因,而土壤容重、土壤水分和温度状况的变化受沙漠化影响较小.%A field investigation on soil chemical and physical properties in different kinds of desertified grassland was conducted during 2009 in the Chenbaer Banner,Hulunbuir Sand Land of Inner Mongolia to understand desertification mechanisms and processes in grassland soils.The results showed that,1) With developing desertification,fine particles (clay and silt) in soil decreased significantly while sand increased significantly,giving a courser soil texture,Loss of soil fine particles was most serious in moderate desertification;2) In the desertification process,changes in soil bulk density and soil temperature were not significant,but soil hardness decreased significantly and soil moisture increased slightly;3) Land desertification resulted in a reduction of soil organic carbon,soil nitrogen and phosphorus,while C/N and soil pH decreased synchronously;4) Changes of soil organic and nutrient content had a significant positive correlation with soil clay and silt contents,while soil hardness had a significant positive correlation with soil fine particles and organic matter.Relativity in soil bulk density,soil temperature and soil moisture with soil texture was not significant;5) In the desertification process,loss of soil clay and silt was the primary mechanism to cause soil coarseness and resulted in a reduction of soil hardness,soil organic carbon and nutrient contents,with lesser effects on soil bulk density,soil temperature and moisture in Hulunbeir sandy land.
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