Fractal geometry concepts have been widely applied as a tool for describing complex natural phenomena, for instance, mechanics and physics of rocks and soils. However, they are seldom used to describe deposited soils. The objectives of this study were to classify soils collected from dam farmlands according to their particle size distributions (PSD) and to examine the relationship between scaling exponents and soil textures (clay and/or sand content). A total of 649 PSD of deposited soils were collected and determined using laser granulometry. The soils were grouped into four texture classes: silt loam, sandy loam, loamy sand, and sand. All the PSD fit the Pore-Solid fractal model well. The mean values of composite scaling constant (c) and fractal dimension (D) differed among soil texture classes. The significant relationships between the values of D and the contents of sand, silt, and clay fractions were found to follow a sigmoid trend. Our results show that the fractal dimension of PSD indicates the degree of soil detachment or soil desertification and the effect of check dams on soil conservation.
1State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation of CAS and MWR; Northwest A&F University, Yangling, China 712100. Dr. Shao is corresponding author. E-mail: firstname.lastname@example.org
2Graduate School of Chinese Academy of Sciences, Beijing, China.
3Institute for a Secure and Sustainable Environment, Department of Biosystems Engineering and Soil Science, The University of Tennessee, Knoxville, TN.
Received November 25, 2008.
Accepted for publication May 13, 2009.
Mingan Shao is a director and a professor at the Institute of Soil and Water Conservation of CAS.
Jie Zhuang is a research director and a research associate professor at the Institute for a Secure and Sustainable Environment, Department of Biosystems Engineering and Soil Science, The University of Tennessee, Knoxville.