东天山喀尔里克山北坡淖毛湖盆地土壤粒度分布特征及成因

Size Distribution and Origin of the Soils on the North Slopes of the Karlik Mountains-Nom Basin in the East Tianshan Mountains

对东天山喀尔里克山北坡-淖毛湖盆地不同类型土壤的粒度进行分析.结果表明:研究区土壤主要由粉粒和砂粒组成,从喀尔里克山北坡、中部地区到淖毛湖盆地,土壤粒度平均值逐渐变大,颗粒分选性差,偏度多属极正偏或正偏,峰态集中在宽、中等和窄3个等级,表明其成土母质较粗、来源相对复杂.土壤的粒度参数Mz、σ、SK和KG值很好地表征了不同土地类型和植被类型及盖度对土壤粒度特征的影响.土壤粒度分维值呈现出随海拔降低逐渐减小的趋势,并且分维值与粘粒含量呈正相关关系.喀尔里克山北坡土壤中粘粒的含量高于中部地区和淖毛湖盆地的土壤,反映出不同地区土壤母质来源和沉积环境的差异.不同地带土壤概率累积曲线的空间变化及综合参数特征表现出地形和气候对颗粒运动形式有一定影响,并且不同地区土壤在成因上既有区别又有联系.

By analyzing the size distribution characteristics of 44samples from 20quadrates on the north slopes of the Karlik Mountains-Nom basin,it is found that clay and sand particles are the main composition of soils in the study areas.From the north slopes of the Karlik Mountains to the middle part-Nom basin,the mean grain sizes become large gradually,but the sorting become worse,with extreme positive skewness or positive skewness,together with kurtosis concentrating in broad,middle and narrow grades,which demonstrate that the parent materials are coarse and the soil origin are complicated.The soil size parameters Mz,σ,SK and KGcommendably mark the impacts of land type,vegetation type and coverage on size characteristics.Soil fractal values in the study areas decrease with decrease of altitude,and have a positive correlation with clay content.Clay content in the north slopes of the Karlik Mountains is more than that in the middle part and the Nom basin,which indicates the discrepancies in the origin for parent materials and the environment for sediment.The spatial variation of probability cumulative curves of soil grain size in different regions shows that landform and climate have impacted on the moving forms of particle transport.There are both distinction and connection in the formation of soils in different regions.