鲁中山区小流域不同土地利用类型的土壤分形及水分入渗特征

为探讨坡耕地土壤入渗性能退化特征与分形机制，对鲁中山区选择典型小流域，运用土壤分形和水文学原理与方法，通过测定坡耕地、弃耕地、生态林地和经济林地4种土地利用类型的土壤分形特征与入渗性能，探讨土壤人渗速率与土壤颗粒分维及孔隙分维的定量关系。结果表明：1）不同土地利用类型土壤稳渗速率表现为坡耕地〉弃耕地〉生态林地〉经济林地，土壤颗粒分维数与孔隙分维数表现为生态林地〉经济林地〉弃耕地〉坡耕地；2）研究区土壤颗粒分维与孔隙分维数之间显著正相关，二者与土壤黏粒及粉粒体积分数显著正相关、与土壤入渗速率显著负相关；3）霍顿入渗模型和幂函数模型比较适用于拟合研究区土壤入渗过程与入渗速率，而菲利浦模型的适用性较差。因此，研究区土壤具有粗骨性砂土的物理特性，坡耕地耕作会加剧土壤中粉粒和黏粒等细粒物质流失，降低土壤颗粒分布与孔隙分布的均匀性及其分维数，导致土壤入渗性能增强但水肥保蓄性能降低。

Fractal features and infiltration characteristics of soil of different land uses in a small watershed of rocky mountainous area in the middle of Shandong Province

For exploring the degradation characteristics of infiltration processes and fractal mechanism in the sloping farmland in a typical small watershed of rocky mountainous area in the middle of Shandong Province, the theories and methods of soil fractal and hydrology were used to analyze the soil infiltration and its quantitative relation with soil particle-size and pore dimension for four kinds of land use types, including sloping land, abandoned farmland, ecological forest, and economic forest. The results showed that： 1） the sequence of soil stability infiltration rate was as follows： sloping farmland 〉 abandoned land 〉 ecological forest 〉 economic forest, and the sequence of soil particle-size and pore dimension was as follows： ecological forest 〉 economic forest 〉 abandoned land 〉 sloping farmland. 2） There were significant positive correlations between the soil particle-size dimension and pore dimension, and both of them had positive correlations with volume percentage of silt and clay, and negative correlations with soil infiltration rate. 3） The Horton model and the power function model were more suitable to simulate the soil infiltration process and infiltration rate in the study area, but Philip infiltration model were not. The conclusions were that the soil in this area displayed a typical fragment of rocky mountainous regions; Due to the loss of the amounts of silt and clay caused by cultivation in the sloping farmland, the uniformity and fractal dimension of soil particle-size and pore distribution were decreased, hence enhancing soil infiltration capacity and decreasing soil water retention capacity.