西南喀斯特地区不同石漠化阶段土壤黏土矿物组成及其含量变异研究

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 illitej 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.%为了探索西南喀斯特地区土壤中黏土矿物组成及其含量的变异规律,以贵州省普定县和荔波县不同石漠化阶段典型土壤的黏土矿物为例,采用X-射线衍射仪图谱分析方法,计算得到黏土矿物组成及其含量,探讨不同石漠化阶段黏土矿物组成变化规律及其含量之间的线性关系.结果表明:不同石漠化阶段黏土矿物的组成是相同的,均为高岭石、蒙脱石和伊利石；在未石漠化、轻度石漠化、中度石漠化阶段,蒙脱石在剖面表层的质量分数分别为27.82％、29.34％、58.32％,高岭石分别为21.39％、31.81％、36.93％,伊利石分别为50.79％、38.85％、4.75％；在西南喀斯特地区,各石漠化阶段伊利石与蒙脱石的含量之间以及伊利石和高岭石的含量之间都呈显著的线性相关,相关系数分别为-0.970 3、-0.945 6；西南喀斯特地区土壤相似的成土作用和成土环境造成了黏土矿物相同的组成,而黏土矿物含量的差异说明各成土作用的程度或阶段是不同的；粉粒中的黏土矿物主要为石英和白云母,而砂砾中的黏土矿物主要为石英.