Soil Crevice Formation and Erosion in Yuanmou Dry-Hot Valley, Yunnan Province, China

The basic characteristics, X-ray analysis and micro-morphology of soil developed from the parent rubified soil is probed. Results show that there are similarities among different types of the rubified soils. The soil clay (D<0.002 mm) contents (Cc) are relatively higher between 29.16% and 80.03%. In addition, organic matter contents are lower between 2.2-6.6 g/kg. The clay minerals in the rubified soils have a high content of 2:1 type swelling minerals, e.g., smectite and vermiculite, which are the basic causes of formation of soil cracks and crevices. Soil micro-morphology characteristics show that microcosmic crevices uni-versally distributed within the tight and compact soil microstruc-ture are the microcosmic characteristics of crevices formation. The soil cracks and crevices change the erosion process. Obviously, well developed soil crevice carries a significant connection with strong soil erosion in Yuanmou, Yunnan province, China. The term "soil crevice erosion" was coincided with the viewpoint put for-ward that soil crevice erosion plays a dominant role in regional and violent soil erosion in this area.