陕北黄土丘陵沟壑区土壤粒径分形特征

应用MS2000激光粒度仪，获取陕北黄土高原米脂县境内10种不同土地利用类型土壤剖面4个层次40个土壤样品的粒径分布（PsD），利用分形几何学方法分析土壤颗粒体积分形特征。结果表明：由于各土壤样品质地相同，分形维数D变化不大，在2．230～2．521之间；〈0．002mm的土壤粒径体积百分含量与D显著相关，而其余各粒径含量均通过与〈0．002mm的相关性对D产生间接影响，表明PSD的D可以充分代表土壤细化的程度与比例。土壤累积体积分数具有非线性特征，1个D值无法表征整个粒径测量范围内的土壤PSD,因此，以15脚为界，确定了2个分形域，分别计算D1和D2，存在D1〉D2的关系，且用D1和D2计算的分裂概率具有尺度依赖性。

Fractal characteristics of soil particles in the Hilly-gully Regions of the Loess Plateau, North of Shaanxi, China

The particle size distributions(PSD) of forty soil samples from the ten kinds of land use and four soil profiles were presented.PSD were measured by Malvern Mastersizer 2000 and analyzed by applying fractal geometry method.Results indicate that there is no significant variation in the fractal dimensions(D) of the soil(between 2.230 and 2.521) due to the same soil texture.There is significantly correlation between volume percentage of <0.002 mm and D values;and D values are affected indirectly by other soil size classes which are related to <0.002 mm.D values of PSD could represent the degree and proportion of the soils finer.In addition,because of the nonlinear characterization of volume cumulative percentage,one D value could not characterize the PSD across the whole size class range of the measurements.Two fractal scaling domains were identified and D₁ and D₂ were calculated,and D₁ is larger than D₂.The boundary between the two domains is located at the particle diameter of 15 μm.Probability of fragmentation calculated by D₁ and D₂ is scale-dependent.