三峡库区典型消落带土壤粒径分布及分形特征

为揭示三峡库区典型消落带土壤的独特性，通过野外调查和实验室定量分析，研究了消落带典型区阶地土壤粒径分布和分形特征。结果表明：该典型消落带土壤分形维数在2.80左右；共有3种质地的土壤，分别是壤质黏土、粉砂质黏土、黏壤土，两种黏土的分形维数不存在显著差异，黏土和壤土的分形维数差异显著且分形维数以黏土的较大。土壤粒径随高程增加表现为由尖峰胖尾分布向尖峰分布变化，在降水和江水的双重作用下，较高高程处小颗粒土粒含量较低，而较低高程处小颗粒土粒含量较高。淹水年限为3 a和1 a的不同植被类型下消落带土壤分形维数不存在显著差异。

Fractal characteristics of soil particles in typical water-level-fluctuating zone in the Three Gorges reservoir area

Fractal is one of the properties of soil.We conducted field investigations and laboratory quantitative analysis to reveal the unique nature of the soil in typical water-level-fluctuating zone of the Three Gorges reservoir area.Soil particle distribution and fractal characteristics in the typical water-level-fluctuating zone was studied.The results showed that,fractal dimension of soil in the zone was around 2.80.There were three kinds of texture of soil: loamy clay,silty clay and clay loam.There was no significant difference in fractal dimension between two kinds of clay.Fractal dimension of clay and loam were significantly different.And fractal dimension of clay was bigger than that of loam.With an increase in altitude,distribution of soil particle changed from peak fat-tailed distribution to peak distribution.Under dual influences of precipitation and river water,the content of small particles of soil at upper elevation was higher than that of soil at lower elevation.There was no significant difference among fractal dimension of soil under different vegetation types with flood for the last three years and the recent one year.