汶川地震区土壤物理性质与渗透性的坡面分布特征

Distribution of Soil Physical Properties and Permeability on Slopes in Wenchuan Earthquake Zone

以汶川县草坡河流域为研究区域,探讨震后4种恢复类型的土壤物理性质和渗透性的坡面分布特征。结果表明,(1)由于地震造成的生态破坏,土壤容重、总孔隙度、非毛管孔隙度和毛管孔隙度等物理性质在坡面分布表现出显著差异。(2)坡面不同部位对自然植物恢复坡面的最大持水量有显著的影响,表现为坡上>坡中(坡下);对有植物长期演替的对照坡面的非毛管持水量有显著的影响,其表现为坡上>坡中>坡下。(3)不同恢复类型土壤入渗率在空间格局上表现不一致,但在时间格局上表现出相同的3区段变化趋势,土壤渗透速率与入渗时间呈非线性关系,经拟合表现出对照地块的土壤渗透数学模型的拟合度最高,且随坡面部位下移拟合度越高。(4)同一坡位的渗透性能在不同恢复类型坡面上表现出明显的差异:对照地块>人工种植>自然恢复>完全裸露,坡位对同一恢复类型土壤渗透率在坡面水平分布上的影响表现为坡上高于坡中和坡下。

The distribution of soil physical properties and permeability with four restoration patterns were studied in Caopo river watershed, which located in Wenchuan county. The results showed： （1）Soil bulk den- sity, total porosity, capillary porosity and noncapillary porosity, and other physical properties in the slope surface distribution showed significant differences, because of the ecological destruction caused by Wenchuan earthquake. （2）The water holding capacity of natural plants returned slope surface biggest had a significant influence on different parts of slope, which showed this order： Up-slope^middle slope （down slope）. The capillary water holding capacity had a significant effect of long-term succession plants recovery type, which showed this order：Up-slope〉middle slope〉down slope. （3）Soil water infiltration rate of different recovery types showed no consistent differences in space pattern, but performed the same 3 section change trend in time pattern. Soil infiltration rate and infiltration time was nonlinear relation, the mathematical model of control soil had a highest fitting degree compared with the other types and degree go higher during downward slope. （4）The permeability of the same slope in different recovery types showed obvious differences which was control plot〉cultivated after the earthquake〉natural restored land〉bare land, permeability of on slope up-slope was higher than the permeability of middle-slop and down slope in the same depth of same recovery type.