Fractal characteristics of soil particles in surface layer after vegetation restoration of small watershed in Wuling mountain

Taking Nverzhai small watershed as study area, this paper calculated fractal dimension of soil particles in surface layers by using weight distribution content based on large-density sampling in watershed. The relationship between fractal dimension and soil characters as well as environmental factors can be analyzed. The results showed that fractal dimension values ranged from 2.2558 to 2.7772, and its variability were not obvious. Fractal dimension values increased with decreasing diameter of soil texture. In soil characters, fractal dimension was negatively correlated with sand (1~0.05mm) content and bulk density. It was positively correlated with clay (<;0.002 mm) content and TN, but had no significant correlations between soil organic matter, TP and available P. In environmental factors, fractal dimension increased with raising of elevation. No significant relations were observed between fractal dimension and soil types as well as slope. Fractal dimension values of forest were generally larger than farmland, this showed that it should mainly persist in the method of vegetation restoration in watershed. This can improve the ability of water conservation of soil and had significance to prevent soil and water loss.