贵州喀斯特山区石漠化土壤理化性质及分形特征研究

Soil Properties and Fractal Features in the Rocky Desertification Process of Karst Regions,Guizhou Province

研究了贵州喀斯特山区石漠化过程中土壤颗粒粗化和理化性质特征,土壤颗粒分形的变化特征,以及分形维数与土壤性状的关系。结果表明:土壤细颗粒含量越少,土壤分形维数越低,表征石漠化程度越高;土壤颗粒分形维数与土壤有机质、容重、粘粉粒含量之间存在显著的线形关系(P<0.01)。分形维数能较好地表征喀斯特石漠化过程中土壤物理性质和养分状况以及石漠化的程度,可作为评价喀斯特地区土壤退化的定量指标之一,对区域生态环境的恢复与重建有着重要的指导意义。

The changes of soil particle size distribution and its fractal features as well as the characteristics of soil chemical properties were studied in the rocky desetifiction process of karst Regions. The relationships between fractal dimension of soil particle distribution and selected soil properties were discussed. The results showed that the surface soil layer （0 -20cm） sandification was more evident after rocky desertification pocess, with soil bulk density being increased by 60%, organic matter contents being decreased by 80%, respectively, in the transformation from non-desertified soil to the most severely desertiffed soil. The fractal dimension of soil particle size distribution ranged from 2. 041 to 2. 872. The more the contents of sand there was, the less the fractal dimension and the higher the desertification degree of soil was found. The fractal dimension decreased from 2. 712 in the non-desertified soil to 2. 125 in the most severly desertified soil in the rocky desertification process. There existed remarkable quantitative relationship between fractal dimension and soil properties. Obviously the fractal model could objectively reflect the texture and fertility status and the degree of soil degradation, so it can be used as a comprehensively quantitative index to evaluate the rocky desertification evolution of soil properties in karst area. The results are important to land and environemental restoration especially in karst rocky desertification region, Guizhou Province in China .