基于GIS的安徽省表层土壤颗粒分形特征研究

Study on the Fractal Characteristic of Topsoil Particle in Anhui Province Based on GIS

以第二次全国土壤普查数据为基础,运用分形模型,计算了安徽省表层（0-20 cm）土壤颗粒的分形维数;结合安徽省1∶50万土壤数据库,利用GIS空间分析技术,探讨了表层土壤颗粒分形维数的空间分布特征及其与环境因子的关系,得出以下几点主要结论：（1）表层土壤颗粒分形维数变化较大,从2.290 3-2.933 2,变幅达0.642 9;从空间分布上看,沿江江南和淮河以北地区分形维数较大,而江淮丘陵地区和大别山区分形维数相对较小。分形维数2.766 4-2.844 7之间的土壤,分布面积最大,达到65 349 km^2,占安徽省总面积的48.28%;（2）不同土壤类型下的土壤颗粒分形维数差别较大。分形维数最大的土壤类型为石灰岩土,达到2.859 7;最小的为粗骨土,只有2.598 1。（3）不同土地利用方式下的土壤颗粒分形维数差别明显。分形维数从大到小的顺序为：草地〉耕地〉园地〉林地。（4）不同海拔下的土壤颗粒分形维数显著不同。随着海拔高度的增加,分形维数有逐渐减小的趋势。

Based on the data of the 2nd State Soil Survey and the fractal model, the soil particle fractal d mensions of topsoil （0-20 cm） in Anhui province were calculated in this paper. Taking advantage of spatial analysis technology of GIS, the spatial distribution characteristic of soil particle fractal dimensions and their relationship with environmental factors were discussed according to the 1 ： 500 000 soil database of Anhui province. The soil particle fractal dimensions of topsoil vary from 2. 290 3 to 2. 933 2. The characteristic of their spatial distribution, generally speaking, is high in the district along as well as in the South of the Yangtze River, so is the district in the North of the Huaihe River, is low in the district of JiangHuai and Dabie Mountain. The area of the soil whose fractal dimensions vary from 2. 766 4 to 2. 844 7 is the largest, which amounts to 65 349 km^2 and accounts for 48.28% of the whole area of Anhui province. The soil particle fractal dimensions of soil group differ widely each other. The fractal dimension of Limestone soils is 2. 859 7 that is the highest while the fractal dimension of Skeletal soils is 2. 598 1 that is the lowest. The soil particle fractal dimensions of different land use types are obviously different each other. The descending order of the fractal dimension is grassland, cultivated land, garden field and forest land. The soil particle fractal dimensions of different altitude differ greatly each other. With the altitude rising, the fractal dimension tends to descend gradually.