我国崩岗侵蚀与国外劣地侵蚀机制类比

作为我国特有的侵蚀地貌,崩岗在长江流域、珠江流域及东南沿海诸河流域集中分布,劣地主要集中发育于环地中海比利牛斯山区、内盖夫沙漠及亚平宁半岛。二者都是世界上侵蚀严重的退化类型,并成为地区生态恢复与重建及人类发展的阻碍因素。通过分析文献,归纳阐述30a崩岗侵蚀与劣地侵蚀机制的研究进展。通过二者的类比,其相似性表现在：1）侵蚀过程由水力-重力混合驱动,岩层结构遭到破坏,稳定性降低;2）地表形态差异较大,沟坡分离,冲积—崩积物堆置于下坡处;3）有机质含量极低,矿质养分稀缺,植被稀少。差异性主要体现在：1）气候类型,地质构造和地貌形态差异明显,植被状况及人为影响程度不同;2）崩壁及其红土层是区分崩岗和劣地垂直剖面的典型特征;3）物化性质、交换性离子活性、分散特性和力学特征存在较大的差异。因此,未来崩岗侵蚀机制研究可关注元素组成、空间分布及交换离子活性等微观领域。

Comparison of mechanism between collapsing erosion in China and overseas badland erosion

As a unique erosive landform in China,collapsing hills occur mostly in Yangtze River Basin,Pearl River Basin and southeast coastal river basins, while badlands are distributed largely in mountainous catchments（ Pyrenees）, the Negev Desert and Apennine Peninsula along the Mediterranean. Both of them are severely erosive degradation patterns around the world and become obstacles to regional rehabilitation as well as human development. The research progress of mechanism between collapsing erosion and badland erosion in the past three decades is reviewed through literature analysis in this paper. The similarities between them are as follows： 1） both of them are driven by the combination of hydraulic power with gravity,which destroy the structure and stability of rock layer as a result; 2） their surface shapes are distinctive,characterized by the detachment of the slope and gully,and alluvium-colluvium deposition along down slope; and 3） the content of organic matters is extremely low,together with scarcity of mineral nutrient and lack of vegetation. The differences between them are：1） the dissimilarities in climatic type,geological structure,topographical features,vegetation conditionsand the extent of anthropogenic impact are remarkable; 2） the collapsing wall and its red soil layer are typical features to distinguish vertical section of collapsing hills and badlands; and 3） physical and chemical properties,exchangeable ion activity,dispersive characteristics and mechanical traits are quite different between collapsing hills and badlands. Future research on mechanism of collapsing erosion should pay more attention to the micro-scale fields such as elemental composition,spatial distribution and exchangeable ion activity.