Fractal characteristics of soil particles and soil water retention curve under typical vegetations in mountainous land of central southern Shandong
Zhang Jie, Gao Peng, Sun Huimin, Zheng Yunlong, Dong Zhi
(College of Forestry, Shandong Agricultural University, State Forestry Administration Forest Ecosystem Research Station of Mountain Tai,Key Laboratory of Soil Erosion and Ecological Restoration of Shandong Province,271018,Tai蒺an,Shandong,China)
Abstract：Soil particle size distribution and soil water retention curve as important physical attributes had important effects on soil erosion and productivity. Based on fractal theory, fractal characteristics of soil particle size distribution and soil water retention curve under five typical vegetations were studied in mountainous land of central southern Shandong. Results indicate that: 1) Monofractal dimension and multifractal parameters of soil particle and fractal dimension of soil water retention curve under different vegetation forms varied greatly, and all showed that: mixed plantation of Quercus acutissima Carr. and Robina pseudoacacia Linn. > mixed plantation of Pinus thunbergii Parl. and Pistacia chinensis Bunge >Pinus thunbergii Parl. > Juglans rigia Linn. > deserted grassland. 2) For the soil fractal dimension,woodland was significantly higher than deserted grassland, and mixed forest was higher than pure forest.3) Fractal dimension of soil had a significantly positive correlation with silt and clay volume content, but a significantly negative correlation with sand volume content. 4) The monofractal dimension of soil particles had significant positive correlation with that of soil water retention curve. A well linear correlation was found between the monofractal dimension of soil particles and fractal dimension of soil water retention curve, which showed that fractal parameters of soil particle size distribution and soil water retention curve could be taken as quantitative indices to reflect soil physical properties. Relationship between fractal dimensions of soil particles and soil water retention curve could be used to describe corresponding soil water retention curve. The results in this paper could be a guidance and theoretical basis for the projects of the coversion of cropland to forest and ecological forest afforestation and their benefit evaluation.
2013, Vol. 11 
