Fractal dimension of soil particle size distribution during the process of vegetation restoration in arid sand dune area
干旱沙区植被恢复过程中土壤颗粒分形特征

This paper analyses the relationships etween the fractal dimension of soil particle size distribution,sand content,silt content,clay content and soil properties during the process of vegetation restoration in arid sand dune area.The result showed that fractal dimension of soil particle increased during the process of vegetation restoration with soil texture getting thinner and fertile.The longer the time of vegetation restored,the greater the fractal dimension of soil particle,the higher the <0.05mm content.The fractal dimensions tend to decrease with the texture coarser at the soil profile.Fractal dimension and soil texture have significant difference within different soil layers.There is a significant positive linear correlation between fractal dimension and the content of <0.05mm soil matter(p<0.0001), and a negative linear correlation between fractal dimension and >0.05mm content.So,<0.05mm content of soil particle size can be regarded as a critical diameter for determining fractal dimension which reflects the content of distribution of particle size fraction,the more the <0.05mm content,the higher the fractal dimension;adversely,the more the >0.05mm content,the lower the fractal dimension.With soil particle size getting thinner,the soil fertility changed remarkably associated with the process of sand dune stabilization.There are significant positive linear correlations between fractal dimension with all soil nutrient status(p<0.0001).Fractal dimension acts as a synthetical index.There a remarkable positive linear correlation with soil properties(p<0.0001).Therefore,the fractal dimension could be used to describe the texture and fertility states,evaluate degree of vegetation restoration in the arid sand dune area,and could be used as an integrated quantitative index to evaluate the degree of soil succession with the re-vegetation practice.