Objective  The fractal dimension characteristics of particle-size distribution of soil profiles along an altitude gradient were revealed in Luofu Mountain, Guangdong.

  Method  Ten soil sampling points at different altitude gradients in Luofu Mountain were selected and soil samples were collected from profile horizons. Soil physic-chemical properties, such as soil particle-size composition, soil organic carbon (SOC), Fe_t, Fe_d, Fe_o, CEC, etc, were determined to analyze the correlation of soil particle fractal dimension with altitude gradients, soil particle distribution (PSD) and chemical properties.

  Result  With the increase of soil depth, soil particle fractal dimension in the Luofu Mountain increased firstly and then decreased with the increase of altitude. The clay content and fractal dimension both decreased, and had extra-significant correlation with altitude. The average of fractal dimension increased from 2.7601 to 2.8954 with soil texture, that is, the fractal dimension increased with the soil texture. The fractal dimension was extra-significantly and negatively related to the sand, whereas, there was extra-significantly positive correlation between fractal dimension and clay. The fractal dimension had extra-significantly or significantly negative correlation with SOC, Fe_o, Fe_o/Fe_d, CEC, but was extra-significantly positively correlated with Fe_t, Fe_d. Path analysis showed that Fe_t, Fe_o/Fe_d had the main influence of chemical properties on soil particle fractal dimension.

  Conclusion  Soil particle fractal dimension could be used to indicate the degree of soil weathering development at different altitudes and be applied as an important diagnostic indicator for soil texture.