紫色土小流域三种土地利用类型土壤颗粒特征

Soil Particles Features under Three Land-use Types in Purple Soil Catchment

在三峡库区忠县虾子岭小流域选择林地、旱地、水田3种土地利用类型采集了63个土样,利用分形维数研究了不同土层深度的土壤颗粒特征。结果表明,紫色土剖面土壤颗粒体积分形维数在2.406～2.551之间,不同土地利用类型分形维数随土壤深度增加变化的趋势不同;土壤颗粒体积分形维数与土粒结构组成存在较强的相关性,受黏粒量影响最为显著,即土壤黏粒量（≤0.002mm）越高,分形维数越大;3种土地利用类型下,土壤颗粒体积分形维数平均值表现为水田〉林地〉旱地。3种土地利用类型之间,除0～20cm土层外其余各层土壤颗粒体积分形维数差异不显著。

Three land-use types,including forest,dry land and paddy land,were collected from Xiaziling catchment in Zhongxian County of the three gorges reservoir area to analyze fractal characteristics of soil particles.The results showed that the value of soil profile fractal dimension ranged from 2.406 to 2.551.The variation trends of D values in soil profiles were different in the three land-use types;there was a close correlation between soil fractal dimension and soil particles content,that was,the more the clay content（ 0.002mm）in the soil,the larger the soil fractal dimensions;The mean soil fractal dimension in soil profile were sequenced as paddy land,forest,dry land,and except for the 0～20cm soil,there was no significant difference among other soil layers of the three land-use types.