title: Fractal scaling of particle size distribution and relationships with topsoil properties affected by biological soil crusts.
abstract: BACKGROUND
  Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions.
  
  
  RESULTS
  To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of successional biological soil crusts (algae, lichens, and mosses crust), as well as the referenced sandland in the Mu Us Desert, Northern China. Relationships between fractal dimensions of soil particle size distribution and selected soil properties were discussed as well. The results indicated that biological soil crusts had significant positive effects on soil physical structure (P<0.05); and soil organic carbon and nutrients showed an upward trend across the successional stages of biological soil crusts. Fractal dimensions ranged from 2.1477 to 2.3032, and significantly linear correlated with selected soil properties (R(2) = 0.494∼0.955, P<0.01).
  
  
  CONCLUSIONS
  Biological soil crusts cause an important increase in soil fertility, and are beneficial to sand fixation, although the process is rather slow. Fractal dimension proves to be a sensitive and useful index for quantifying changes in soil properties that additionally implies desertification. This study will be essential to provide a firm basis for future policy-making on optimal solutions regarding desertification control and assessment, as well as degraded ecosystem restoration in arid and semiarid regions.
authors: College of Soil & Water Conservation, Beijing Forestry University, Beijing, China.
authors: Guang-Lei
authors: GL
authors: Gao
authors: College of Soil & Water Conservation, Beijing Forestry University, Beijing, China ; Yanchi Research Station, Yanchi, China.
authors: Guo-Dong
authors: GD
authors: Ding
authors: College of Soil & Water Conservation, Beijing Forestry University, Beijing, China ; Yanchi Research Station, Yanchi, China.
authors: Bin
authors: B
authors: Wu
authors: College of Soil & Water Conservation, Beijing Forestry University, Beijing, China ; Yanchi Research Station, Yanchi, China.
authors: Yu-Qing
authors: YQ
authors: Zhang
authors: College of Soil & Water Conservation, Beijing Forestry University, Beijing, China ; Yanchi Research Station, Yanchi, China.
authors: Shu-Gao
authors: SG
authors: Qin
authors: College of Soil & Water Conservation, Beijing Forestry University, Beijing, China ; Yanchi Research Station, Yanchi, China.
authors: Yuan-Yuan
authors: YY
authors: Zhao
authors: College of Soil & Water Conservation, Beijing Forestry University, Beijing, China.
authors: Yan-Feng
authors: YF
authors: Bao
authors: College of Soil & Water Conservation, Beijing Forestry University, Beijing, China.
authors: Yun-Dong
authors: YD
authors: Liu
authors: College of Soil & Water Conservation, Beijing Forestry University, Beijing, China.
authors: Li
authors: L
authors: Wan
authors: College of Soil & Water Conservation, Beijing Forestry University, Beijing, China.
authors: Ji-Feng
authors: JF
authors: Deng
mesh_terms: D002681:China; D003889:Desert Climate; D017753:Ecosystem; D017709:Fractals; D010316:Particle Size; D012987:Soil
chemical_list: D012987:Soil