Fractal Characteristics of Soil Particle-Size Distributions Under _Different Landform and Land-Use Types | 不同地貌类型及土地利用方式下土壤粒径的分形特征

Chinese. 研究不同地貌类型及土地利用方式下土壤粒径的分形特征，为黄土高原沟壑区土壤侵蚀的防治和种植业结构调整提供理论指导。对甘肃省南小河沟流域不同地貌(塬面、坡面、沟道 )、不同土地利用方式（耕地、林地、荒地等）的土壤进行分层（0~20，20~60（或20~40，40~60），60~100 cm）取样，采用筛析法和吸管法相结合的方法，对样品的土壤颗粒含量和质量分形维数进行测定，利用土壤粒径分形原理，研究土壤分形维数与土壤质地、地貌类型和土地利用方式的关系。粘粒含量对土壤质量分形维数有显著影响，砂粒和粗粉粒含量的影响较小。土壤粘粒含量与土壤质量分形维数在不同地貌类型及土地利用方式的土壤剖面上表现出相同的变化规律。土壤质量分形维数与地貌和土地利用类型有关。土壤质量分形维数和土壤粘粒含量可以作为反映土壤物理性质和质量的潜在性指标。

English. The research was to provide theoretical guidance for the prevention of soil erosion and planting structure adjustment by studying fractal characteristics of soil particle-size distributions under different landforms and land-use types. Soil particle-size distribution (PSD) is one of the most important physical attributes due to its strong influence on soil properties related to water movement, productivity and soil erosion. The fractal and multifractal measures are useful tools in identifying soil PSD with different taxonomy. Land-use type, as one of the important factors affecting soil PSD, has been paid little attention in the previous research. In this paper, the theory of soil particle-size fractal was applied to characterize PSD in soils with the same taxonomy and different land-use types. Then the effects of land use on the fractal and multifractal parameters were analyzed. The study was conducted on the loess hilly areas of the Loess Plateau in Nanxiaohegou basin of Gansu. Soil was sampled from 18 land use types. The soil PSDs were obtained by sieving and pipette methods. The result showed that: the mass fractal dimension of soil particles was significantly correlated with the mass percentage of soil clay content; both the mass percentage of soil clay content and the mass fractal dimension of soil particles showed the same tendency of increasing the soil layer, and the mass fractal dimension was related to the land uses and topographic feature. Thus they could be potential parameters to reflect soil physical properties influenced by land use. More significant result is required in the future study to test the applicability of fractal parameters in characterizing land use effect on soil particle-size distributions.