陕北神木矿区土壤颗粒体积分形特征及意义

Volume Fractal Characteristics and Significance of Soil Particles in the Shenmu Colliery in North Shaanxi Province

土壤由母质风化而成,土壤的颗粒组成继承了母质的许多特征,分形特征便是其中之一。土壤颗粒分形特征不仅影响土壤的水力状况和肥力特征,而且与土壤侵蚀和退化状况直接相关。利用MS 2000激光粒度分析仪,测定神木矿区凉水井煤矿、四道沟煤矿和红碱淖原生态保护区3个样区60个土样的粒径分布状况,运用土壤体积分形模型计算土壤颗粒体积分形维数(D),并分析土壤理化性质与D值之间的关系。结果表明:样区内D值在1.95～2.68之间,平均D值为2.42。3个样区平均D值关系为:四道沟煤矿(2.47)>原生态区(2.43)>凉水井煤矿(2.33)。D值与黏粒和粉粒含量呈正相关关系,与砂粒含量呈负相关关系,相关性均达到极显著水平(P<0.01)。D值与土壤pH、全磷含量呈极显著正相关,而与有机质、全氮、速效钾含量相关性均未达到显著水平。此外,地表主要植被类型对D值的影响表现为:长芒草地>柠条地>沙打旺地>茵陈蒿地>乔木林地。

Soil is produced from the parent material by weathering. Soil particle composition inherits many properties of parent material, one of which is fractal dimension. PSD affects not only the soil hydraulic, conditions and fertility, but also relates directly to the soil erosion and degradation. In this study, a laser particle size analyzer was used to measure the particle size distribution of 60 soil samples collected from the Liangshuijing, Sidaogou and Hongjiannao coal mining areas in Shenmu Colliery. Soil particle volume fractal dimension （D） was obtained with volume fractal dimension model. In the meantime the relationships between D value and soil physicochemical prop- erties were analyzed. The results showed that the D value varied in a range of 1.95 - 2.68, and its average was 2.42. The average D values of the Sidaogou, Hongjiannao and liangshuijing coal mining areas were 2.47, 2.43 and 2.33 respectively. There was a significant positive correlation between D value and clay and silt content （P 〈 0. 01 ）, but a significant negative one between D value and sand content （P 〈0.01 ）. There was also a significant positive correlation between D value and pH value and total phosphorus content, but there was no significant correlation between D value and the contents of organic matter, total nitrogen and available potassium. Moreover, the effect of diminant vegetation types on D value was in an order of Stipa bungeana 〉 Caragana microphylla 〉 Astragalus adsurgens 〉 Artemisia CapiUaris 〉 arbors.