摘要
In order to find the composition and content variation of clay mineral of soil under different stages of rock desertification in Karst Region,Southwest China,taking the clay mineral of soil under different stages of rock desertification in Puding County and Libo County of Guizhou Province as an example,composition and content of clay mineral were calculated by the means of X-ray diffraction spectrogram,and the composition and linear relationships among the contents of clay mineral under different stages of rock desertification were discussed.The results showed that the composition of clay mineral under different stages of rock desertification were same,all of them were composed of kaolinite,montmorillonite and illite;mass fractions of montmorillonite in the section surface were 27.82%,29.34% and 58.32% under the non-degraded,light and moderate stages of rock desertification,respectively,and those of kaolinite were 21.39%,31.81% and 36.93%,and those of illite were 50.79%,38.85% and 4.75%;the relationships between mass fractions of illite and montmorillonite and between that of kaolinite and illite under different stages of rock desertification in Karst Region were significant,and the correlation coefficients were-0.970 3 and-0.945 6,respectively;the compositions of clay mineral were same because the pedogenesis and soil-forming condition in Karst Regions were similar,and the difference of contents of clay mineral indicated the different pedogenesis in terms of degree and stage;the clay minerals were mainly quartz and muscovite in silt,and mainly quartz in gravel.