秦川盆地土壤粘土矿物分析

Analysis on soil clay minerals in Qinchuan Basin, Gansu, China

用X射线粉晶衍射分析法研究了秦川盆地灰钙土、耕种灰钙土、沙田灰钙土、沙田盐化灰钙土、旱盐土5种土壤的粘土矿物组成。研究结果表明,5种土壤粘土矿物含量的平均值分别为1.14 %、1.18 %、1.78 %、0.72 %、2.26 %;秦川盆地5种主要土壤的粘土矿物组成是相似的,土壤粘土矿物以伊利石为主,其次为绿泥石,不含高岭石和蒙脱石以及由高岭石、蒙脱石与伊利石和绿泥石组成的混层粘土矿物;这反映秦川盆地的成土环境为碱性还原环境,说明土壤的发育程度比较低;粘土矿物随着土层深度的增加而增加,说明深层的风化程度较高,粘化作用较强,因而具有较高的土壤粘土矿物含量。

The typs and content of soil clay minerals in Qinchuan Basin, Gansu, China are analysised with X-ray powder diffraction. The results show that the type and amount of the main soil in Qinchuan Basin,sierozem(gray desert soil),till sierozem,sand covered sierozem,sandy salted soil and dry salt soil,are similar. The average amount of the soil clay minerals in the 5 main type soils are 1.14 %, 1.18 %, 1.78 %, 0.72 % and 2.26 % respectively. The main type of clay mineral are hydromica and chlorite,there are no kaolinite, montmorillonite and mixtures mingled with kaolinite, montmorillonite hydromica and chlorite. This indicates that the soil forming process still stays in alkaline environment, the weathering degree of the materials is low. The amount of soil clay mineral increases with the depth of the soil section going down, it indicates that weathering degree of lower layer soil is more than it of upper layer soil.