南方水蚀区不同侵蚀程度土壤粒径分形研究

土壤粒径分布是土壤和环境要素综合作用的结果，因而可藉以指示环境要素的某种性状。对南方水蚀区不同侵蚀程度下土壤粒径的分布特征进行研究，计算土壤粒径分布分形维数值，并分析其与土壤质地和土壤侵蚀程度的关系。结果表明，研究区土壤质地主要为砾石土，其2 mm以下的体积分形维数和重量分形维数分别介于2.52～2.99和2.48~2.73之间，粒径重量累积百分比在2 mm处产生显著变化，粒径域的重量分形维数在2 mm以上和2 mm以下分别为1.79~2.81和2.52~2.79。2 mm以上粒径域的重量分形维数与土壤质地和土壤侵蚀程度呈显著的相关性。土壤质地越细，或土壤侵蚀越轻微，2 mm以上粒径域的重量分形维数越大，反之亦然。故土壤2 mm以上粒径域的重量分形维数可综合表征研究区土壤质地和土壤侵蚀程度。

Study on the Fractal Dimension of Soil Particle Size Distribution in Areas with Different Water-Erosion Degrees in Southern China

Soil particle size distribution is the result of interactions between soils and their environmental factors, so it can reflect certain properties of environmental factors. Aimed at analyzing the characteristics of particle size distribution of the soil under different water-erosion degrees in southern China, the fractal dimension of the soil particle size distribution was calculted, and the relationships between the fractal dimension values and soil textures or soil erosion degrees was explored. The results showed that, the gravelly soil dominated the soil textures in the study area. The volume and weight fractal dimension values of the soil particles less than 2 mm were between 2.52 to 2.99 and 2.48 to 2.73, respectively. The accumulated percentage of weight changed significantly at the soil particle size of 2 mm, and the weight fractal dimension values were 1.79~2.81 and 2.52~2.79 for the soil particle size greater than 2 mm and lower than 2 mm, respectively. The weight fractal dimension values for the soil particle size greater than 2 mm were significantly related to both soil textures and soil erosion degrees. The finer the soil texture or the less severely the soil eroded, the greater the weight fractal dimension for the soil particle size which is greater than 2 mm, and vice versa. Therefore, the weight fractal dimension for the soil particle greater than 2 mm can indicate the soil texture and soil erosion degree in the study area.