应用XRD光谱研究水旱利用方式下盐碱土粘粒矿物演化特性

以吉林省典型盐碱土为研究对象，对比分析水田与旱田利用方式下土壤粘粒矿物的组成特征，并利用X射线衍射(XRD)光谱研究两种利用方式下粘粒矿物的演化规律。结果表明，水田利用方式下，盐碱土各项理化性质均优于旱田利用，且水田利用较旱田利用更能促进盐碱土颗粒风化，提高粉粒颗粒含量。水田利用下土壤有强烈的脱钾过程，粘粒矿物的水化程度较高，伊利石结晶度降低。XRD光谱分析表明，两种利用方式下粘粒矿物组成相似，但衍射峰的强度及峰位存在差异。旱田利用的盐碱土粘粒矿物演变过程主要为S/I混层矿物→蛭石，水田方式下演变过程则主要为黑云母→伊利石和S/I混层矿物→蛭石→高岭石;长期水田利用后的盐碱土会出现一类羟基化的“绿泥石化”矿物。研究结果表明水田利用更有助于改善土壤结构，培育高肥力土壤，对盐碱土的改良效果较好。利用XRD光谱分析方法，较为全面的测定了粘粒矿物的各项特性，并针对两种利用方式进行对比分析，是土壤矿物研究的新视角。

Research on Characteristics of Soil Clay Mineral Evolution in Paddy Field and Dry Land by XRD Spectrum

The present paper took the typical saline-alkali soil in Jilin province as study object, and determinated the soil clay mineral composition characteristics of soil in paddy field and dry land. Then XRD spectrum was used to analyze the evolutionary mechanism of clay mineral in the two kinds of soil. The results showed that the physical and chemical properties of soil in paddy field were better than those in dry land, and paddy field would promote the weathering of mineral particles in saline-alkali soil and enhance the silt content. Paddy field soil showed a strong potassium-removal process, with a higher degree of clay mineral hydration and lower degree of illite crystallinity. Analysis of XRD spectrum showed that the clay mineral composition was similar in two kinds of soil, while the intensity and position of diffraction peak showed difference. The evolution process of clay mineral in dry land was S/I mixture→vermiculite, while in paddy field it was S/I mixture→vermiculite→kaolinite. One kind of hydroxylated ’chlorite’ mineral would appear in saline-alkali soil in long-term cultivated paddy field. Taking into account that the physical and chemical properties of soil in paddy field were better then those in dry land, we could know that paddy field could help much improve soil structure, cultivate high-fertility soil and improve saline-alkali soil. This paper used XRD spectrum to determine the characteristics of clay minerals comprehensively, and analyzed two kinds of land use comparatively, and was a new perspective of soil minerals study.