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本研究以山西吉县蔡家川流域内不同树龄的刺槐、油松纯林及其撂荒地为研究对象,应用Microtrac S3500激光粒度分析仪,对各地类土壤剖面中8个层次168个土壤样品的微团聚体组成进行测定后,利用分形几何学方法分析了土壤微团聚体的分形特征。结果表明:土壤微团聚体体积分形维数D随土层深度增加呈现递减趋势,平均值为2.22,变化于1.75~2.7之间。各地类土壤微团聚体体积分形维数D与<0.005 mm粒级土壤微团聚体体积分数呈极显著正相关关系,相关系数R均大于0.95,与其它粒级土壤微团聚体体积分数相关性不显著。根据土壤养分状况、土壤物理性质与土壤微团聚体分形维数成反比的研究结论,各地类0~20 cm深度土层的肥力状况和物理性质较20~40 cm土层好,撂荒地土壤肥力状况和物理性质最差,刺槐林地的肥力状况和物理性质好于油松林地,随着树龄的增加,土壤肥力和物理性质有下降趋势。
In this study, the black locusts, the pure stands of Pinus tabulaeformis and its fallow fields were studied in the Caijiachuan valley of Ji County, Shanxi Province. Microtrac S3500 laser particle size analyzer was used to study the microaggregation of 168 soil samples from 8 soil layers After determining the body composition, the fractal characteristics of soil microaggregates were analyzed by fractal geometry method. The results showed that the volume fractal dimension D of soil microaggregates showed a decreasing trend with the increase of soil depth, with an average value of 2.22 and a variation of between 1.75 and 2.7. The volume fractal dimension D of soil microaggregates was significantly and positively correlated with the volume fraction of soil microaggregates <0.005 mm, the correlation coefficient R was greater than 0.95, and the correlation with the volume fraction of other soil microaggregates was not significant Significant. According to the results of soil nutrient status and soil physical properties inversely proportional to the fractal dimension of soil microaggregates, the soil fertility and physical properties of 0-20 cm soil depth are better than those of 20-40 cm soil depth, The condition and physical properties of Robinia pseudoacacia were the worst. The fertility status and physical properties of Robinia pseudoacacia woodland were better than that of Pinus tabulaeformis woodland. With the increase of tree age, soil fertility and physical properties tended to decline.