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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。
The fractal characteristics of soil particles in several woodlands in the Simian Mountain of Chongqing were studied by using the fractal model. The relationship between the fractal dimension and the particle size distribution and its influencing factors were also discussed. The results showed as follows: ①The order of the average fractal dimension of 0-60cm soil was as follows: coniferous forest> mixed coniferous and broad leaf forest> bamboo grove> broadleaf forest, broadleaved forest and bamboo grove soil had relatively loose and good permeability structure, The coniferous forest and mixed forest soil texture is fine, with better water holding fertilizer performance. With the increase of soil depth, the fractal dimension of broad-leaved forest soil decreased most significantly, while that of bamboo forest increased, while that of coniferous forest and coniferous-broad-leaved forest decreased insignificantly. This change is completely consistent with the change of clay content in the four sections. (3) Fractal dimension can characterize the size and amount of soil particles, but different degrees of particle size reflect different degrees, which are mainly determined by clay content (R = 0.964), negatively correlated with sand content (R = -0.873) And powder content was not significant (R = -0.004). ④ Multiple regression analysis showed that the fractal dimension was related to organic matter content, total nitrogen, available phosphorus, available potassium, capillary porosity, non-capillary porosity, saturated water content, capillary water holding capacity and field water holding capacity.