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选择科尔沁沙地典型沙丘-草甸相间地为研究区,利用土壤颗粒的体积分形模型计算了研究区49个采样点土壤颗粒的分形维数,并建立了分形维数与土壤颗粒不同粒级间的相关关系,以探讨半干旱寒冷地区土壤颗粒的分形特征与土壤物理性质以及养分含量之间的关系。结果表明:(1)研究区土壤颗粒的分形维数为1.33~2.50,变幅较大,且呈现出自中部的草甸、农田地带向南、北方向的沙丘地带递减的趋势;土壤颗粒的体积分形维数依照流动沙丘-半流动半固定沙丘-固定沙丘-农田-草甸的顺序而递增。(2)土壤颗粒的分形维数与黏粒、粉粒含量显著正相关,与砂粒含量显著负相关,且表现出明显的对数关系。100μm是影响土壤颗粒分形维数变化的分界粒径,大于该粒径的颗粒含量越高,土壤颗粒的分形维数越小;反之越大。(3)分形维数与土壤养分含量相关显著,土壤颗粒的分形维数与电导率、pH值及有机质、全氮、全磷含量均显著正相关,但与全钾含量负相关。在分形维数大于2时,基本与土壤饱和含水率正相关、与干容重负相关。
The typical sand dunes and meadow in Horqin sandy land were chosen as the study area. The fractal dimension of 49 soil samples in the study area was calculated by the volume fractal model of soil particles. To explore the relationship between fractal characteristics of soil particles and soil physical properties as well as nutrient content in semi-arid and cold regions. The results showed that: (1) The fractal dimension of soil particles in the study area ranged from 1.33 to 2.50, showing a large amplitude with a decreasing trend in the meadows from the middle and the farmland to the south and north directions. The volume of soil particles Fractal dimensions increase in the order of mobile sand dune - semi-mobile semi-fixed sand dune - fixed sand dune - farmland - meadow. (2) The fractal dimension of soil particles is significantly and positively correlated with clay and silt content, and is negatively correlated with sand content, and shows a significant logarithmic relationship. 100μm is the demarcation particle size that affects the change of fractal dimension of soil particles. The higher the particle size is, the smaller the fractal dimension of soil particles is; on the contrary, the larger the particle size. (3) The correlation between fractal dimension and soil nutrient content was significant. The fractal dimension of soil particles was significantly and positively correlated with conductivity, pH, organic matter, total nitrogen and total phosphorus, but negatively correlated with total potassium content. When the fractal dimension is more than 2, it is basically related to the soil saturated moisture content and to the dry weight.