The results indicate that : 1 . the main physical and chemical characteristics vary regularly : with rising of the altitude , there is a transition from silt > sand > clay to sand > silt > clay in the mechanical composition ; the argic horizon emerges below the altitude of 1600 meters ; the content of organic matter is enrichment , the content of organic carbon of epipedon is higher than 20 g / kg , while the content of organic carbon increases with increasing of altitude , and in the altitude of 3500 - 3700meters , the soils under the meadow have the maximum content organic carbon ; the soils appear acid - slightly acid reaction , the ph decreases appreciably and acid strengthen with increasing of altitude ; the soils higher than the altitude of 2500 meters are base unsaturated , indicating the soil leaching is strong , the ph and bs are distinct plus correlated ; the contents of sio2 , al2o3 , and fe2o3 of the soil body and clay are all relatively stabilization ; in the soil body , the content of sio2 is much high and cao is very little , the total contents of sio2 , a12o3 and fe2o3 occupy 92 % of the mineral parts , the sequence of mineral elements is : sio2 > al2o3 > fe2o3 > k2o > mgo > cao > tio2 > mno 研究结果表明： 1太白山南坡土壤的主要理化性质随海拔高度的上升呈有规律的变化：随海拔高度上升，机械组成由粉粒砂粒粘粒逐渐过渡到砂粒粉粒粘粒，海拔1600m以下出现粘化层；土壤有机质丰富，表层有机碳含量一般在20g kg以上，有机碳含量随海拔高度升高而相应增加，海拔3500 3700m的灌丛草甸植被下有机碳含量最高；土壤呈酸性或微酸性，并随海拔上升， ph值略微降低，酸性增强，海拔2700m以上的土壤多呈盐基不饱和状态，表明土壤淋溶作用较强， ph值和盐基饱和度呈极显著正相关；土体与粘粒中的sio _ 2 、 al _ 2o _ 3 、 fe _ 2o _ 3含量相对比较稳定，土体中sio _ 2含量较高， cao含量较少， sio _ 2 、 al _ 2o _ 3和fe _ 2o _ 3含量之和约占土壤矿质部分的92 ，矿质元素含量的顺序依次为： sio _ 2 al _ 2o _ 3 fe _ 2o _ 3 k _ 2o mgo cao tio _ 2 mno 。
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