中文摘要：

运用分形模型研究了重庆四面山几种林地土壤颗粒的分形特征,并探讨了分形维数与粒级分布的关系及其影响因素。结果表明：①0-60cm土壤分形维数平均值的顺序为：针叶林〉针阔混交林〉楠竹林〉阔叶林,阔叶林和楠竹林土壤具有相对疏松、通透性好的结构,而针叶林和混交林地土壤质地较细,具有较好的持水保肥性能。②随着土层深度的增加,阔叶林地土壤的分形维数减小最为显著,楠竹林地呈增大的趋势,而针叶林和针阔混交林地减小不显著。这种变化与4个剖面上粘粒含量的变化规律完全一致。③分形维数能够表征土壤颗粒的大小和数量,但对不同粒级颗粒含量的反映程度不同,主要由粘粒含量决定（R=0.964）,与砂粒含量显著负相关（R=-0.873）,与粉粒含量相关关系不显著（R=-0.004）。④多元回归分析表明,分形维数与有机质含量、全氮、有效磷、速效钾、毛管孔隙度、非毛管孔隙度、饱和含水量、毛管持水量和田间持水量具有一定的相关性。

英文摘要：

Based on fractal theory,fractal characteristics of different forest soil were studied in Simian mountains,Chongqing,and correlation of fractal dimension with particle size distribution and related affecting factors were also discussed.Results indicated that there were significant differences：①In the soil profile（0-60 cm）,average fractal dimensions were as follows： conifer forest landconifer-broadleaf forest landPhyllostachys pubescens landbroadleaf forest land.Broadleaf forest and Phyllostachys pubescens land had relatively loose structure with better permeability while conifer-broadleaf forest and conifer forest land had better water holding capacity and fertilizer performance.②In the soil profile,fractal dimension of broadleaf forest land decrease significantly,while Phyllostachys pubescens land increase,the change of conifer-broadleaf forest land and conifer forest land are not evident.These changes agreed well with the tendency of clay content.③Fractal dimensions could be used to describe particle size distribution and the reflections are different.Fractal dimension mostly depends on clay content（R=0.964）and had a significant negative correlation with sand content（R=-0.873）,but the correlation with silt content was not obvious（R=-0.004）.④Multivariate regression analysis showed that fractal dimension had relativity with organic matter content,total nitrogen,rapidly available phosphorus,rapidly available kalium,capillary porosity,non-capillary porosity,saturated water content,capillary moisture capacity and field capacity.