Fractal method is a new method to estimate soil structure. It has been shown to be a useful tool in studies related tophysical properties of soil as well as erosion and other hydrological processes. Fractal dimension was used to study thesoil structure in soil at different stages of vegetative succession on the Ziwuling Mountains. The land use and vegetationtypes included cultivated land, abandoned land, grassland, two types of shrub land, and three types of forests. Thegrassland, shrub land, and forested areas represented a continuum in vegetative succession that had occurred naturally,as the land was abandoned in 1862. Disturbed and undisturbed soil samples were collected from ten vegetation types fromdepths of 0-10, 10-20, and 20-30 cm on the Ziwuling Mountains, at a site with an elevation of about 1 500 m. Particle sizedistribution was determined by the pipette method and aggregate size distribution was determined by wet sieving. Theresults were used to calculate the particle and aggregate fractal dimension. The results showed that particle and aggregatefractal dimensions varied between vegetation types. There was a positive correlation between the particle fractal dimensionand the weight of particles with diameter < 0.001 mm, but no relationship between particle fractal dimension and the otherparticle size classes. Particle fractal dimension was lower in vegetated soils compared to cropland and there was noconsistent relationship between fractal dimension and vegetation type. Aggregate fractal dimension was positivelycorrelated with the weight of > 0.25 mm aggregates. Aggregate fractal dimension was lower in vegetated soils comparedwith cropland. In contrast to particle fractal dimension, aggregate fractal dimension described changes in soil structureassociated with vegetative succession. The results of this study indicate that aggregate fractal dimension is moreeffective in describing soil structure and function compared with particle fractal dimension.
