三峡库区不同土地利用类型土壤颗粒分形特征

Fractal Characteristics of Soil Particles Under Different Land Use Types in the Three Gorges Reservoir Region

采集三峡库区忠县石宝寨4种不同土地利用类型土壤剖面0-40cm土层3个层次12个土壤样品,通过计算和测定土样颗粒体积分形维数及基本性质,以期说明三峡库区中性紫色土土壤颗粒体积分形特征及其与土壤基本性质间的相关性。结果表明,研究区中性紫色土土壤剖面(0-40cm)土壤颗粒体积分形维数D值介于2.638～2.674之间。随土层深度的增加D值总体呈增加趋势,不同土地利用类型之间的D值存在差异,表现为林地<果园<菜地<水田;D值与土壤粘粒(<0.002mm)体积百分含量呈极显著正相关关系(P<0.01),与土壤粉粒(0.002～0.05mm)体积百分含量的相关性不强,而与砂粒(>0.05mm)体积百分含量呈极显著负相关关系(P<0.01);D值与土壤有机质、全氮、全磷含量不存在显著相关性。

For searching the characteristics of volume fractal dimension of purple soil particle in the Three Gorges reservoir region and the relationship between volume fractal dimension and the main features of purple soil,twelve soil samples from the four kinds of land use and three soil profiles within 0-40 cm depth were presented and tested,and the soil particle size distributions were measured by Mastersizer 2000.Some conclusions could be drawn as follows：The volume fractal dimensions of neutral purple soil（0-40 cm） ranged from 2.638 to 2.674.The volume fractal dimension increased with the soil depth under single land use,and fractal dimension value of different land use appeared in the order： Forest landorchardvegetable fieldspaddy fields.The volume fractal dimension of soil particle had a highly significant positive correlation with the volume percentage of soil clay（0.002 mm） contents,a highly significant negative correlation with the volume percentage of soil sand（0.05 mm） contents,in which there was lower correlation with the volume percentage of silt（0.002~0.05 mm） contents.In addition,the contents of soil organic matters,soil total nitrogen and soil total phosphorus had no significant correlations.