花岗岩山坡A-C结构土壤下典型植被优先流发育特征研究

Study on the Characteristics of Preferential Flow of Typical Vegetation in A-C Structure of Soils on a Granite

土石山区A-C结构土壤条件下土薄石多,不同植被条件下优先流发育的是否受到土壤厚度、石砾含量的影响尚不明确。本研究利用染色示踪法与图像处理技术,对鲁中南花岗岩山坡2种土层厚度条件下的黑松林、刺槐林(土层厚度约为40 cm)和板栗林(土壤厚度约为80 cm)优先流染色剖面分布特征及其影响因素进行研究。结果表明,3种植被覆盖下基质流发育深度和最大入渗深度非均匀系数差异不显著(P>0.05),但土层较厚的板栗林最大入渗深度、优先流比、长度指数均明显较高(P<0.05),因此土层较厚条件下优先流发育程度较高。根长密度、土壤容重、总孔隙度、非毛管孔隙度、石砾含量,是影响各植被条件下优先流路径选择的重要因素,但土壤物理性质和根系的剖面分布变化是影响不同植被条件下优先流发育差异的关键因素。研究结果有助于进一步揭示土石山区优先流产流机制。

In the hilly area with A-C structure soil,the soil is thin and the rocks are abundant.It is not clear whether the preferential flow development under different vegetation conditions is affected by soil thickness and gravel content.In this study,the staining tracer method and image processing technology were used to study the spatial distribution of preferential flow staining profiles and its influencing factors in black pine forest,robinia forest(soil thickness about 40 cm)and chestnut forest(soil thickness about 80 cm)with different soil thickness.The results showed that the development depth of the substrate flow and the non-uniform coefficient of the maximum infiltration depth under different vegetation had no significant difference(P>0.05).but the maximum infiltration depth,preferential flow ratio,length index under chestnut forest with thicker soil layer were significantly higher(P<0.05).Therefore,the development degree of preferential flow was higher in the forest with thicker soil layer.The root length density,soil bulk density,total porosity,non-capillary porosity and gravel content are the important factors affecting the selection of preferred flow path under different vegetation conditions,but the changes in profile distribution of soil physical properties and root density was the key factors affecting the difference of preferred flow development under different vegetation conditions.The results of this study are helpful to further reveal the mechanism of preferential flow production in earth-rock mountainous areas.