贵州岩溶地区地质条件对水土流失的影响

The affection of geological condition on water loss and soil erosion in Guizhou Karst mountainous area

通过对贵州岩溶地区水土流失的调查研究表明,地质条件是控制水土流失的一个主导因子,碳酸盐岩石有成土速度慢、成土量小、地表径流不易形成、水土流失量小而流失隐患大的特点;碳酸盐岩石在水土流失方面的类型分异由含泥量决定,可分为纯灰岩、泥灰岩、纯白云岩及泥质白云岩4类。石灰岩类形成的土壤坚实度较为稳定,为4.0～8.0之间,而白云岩类形成的土壤坚实度较不稳定,为3.0～13.5之间。同时,断层构造、节理裂隙以及岩层与坡向的关系均对水土流失特征有明显的影响。

By investigating and researching on water loss and soil erosion in Guizhou Karst mountainous areas, it indicates that the geological condition is a main factor controlling water loss and soil erosion, that carbonate rocks have the characteristics of slow soil formation and small soil quantity, of being difficult to form surface run off , and of having small quantity and great potential danger on soil erosion. Carbonate rock'types on water loss and soil erosion could be classified by rock's clay quantity into pure limestone, marlite , pure dolomite and pelitic dolomite. The soil's hardness values of limestone are stable, which is between 4.0 to 8.0, but that is unstable by dolomite, which is between 3.0 to 13.5. On the other hand, the characteristics of water loss and soil erosion are affected by geologic structures of faults, the relation between the rock formation and the slope direction. 