Fractal features of soil particles under different land uses in a coastal reclamation area

The fractal feature of soil particles is an important factor to characterize the interaction between vegetation and soil environment. In this study, the fractal dimension of soil particles and their relationship with soil particle size distribution and soil physical and chemical properties were studied in terms of two land uses, long-term abandoned land and paddy field in a reclamation area along the coast of Jiangsu Province. The results showed that the fractal dimension of soil particles in coastal reclamation area was between 2.16~2.21, and there was significant difference between these two land uses. The fractal dimension of soil particles in the wasteland soil was larger than that of the cultivated soil, and agricultural reclamation reduced the fractal dimension of soil particles in the coastal reclamation area. The fractal dimension of soil particles was positively correlated with the clay, fine silt and coarse sand, but negatively correlated with the content of very fine sand, fine sand and medium sand. The particle size of 0.05 mm was a threshold size that affected the fractal dimension of soil particles in the coastal reclamation area. The electrical conductivity and soluble salt cation content of wasteland soil were higher than those of paddy soil. Rice farming was beneficial to reduce the soil salt content in coastal reclamation area. The fractal dimension of soil particles was significant positively correlated with the organic matter content and the contents of water-stable aggregates with particle size >0.25 mm. The fractal dimension of soil particles could be used as one of the quantitative indicators to represent the characteristics and changes of soil physical and chemical properties, and to evaluate the development and evolution of saline soil in coastal reclamation area.