The Dupang Mountain is located at 25°09'-25°50'N,111°17'-111°51'E in Hunan.The soil formation in this region is characterized by stronger desilicification and allitization,with clay minerals dominated by kaolinite in B horizon,a lower silica-alumina ratio being generally below 2.5,a higher organic matter content and a strong eluviation in the soils on the upper part of vertical sequence.With distinct zonality,the vertical sequence of soil distribution from the upper part downwards is in the order of mountain red earth (below 700 m)-mountain yellow earth (700-1550m)-mountain yellow-brown earth (1550-1950 m)-mountain shrubby-medow soil(>1950 m).Mountain yellow earth is of most importance in the soil sequence,of which the properties indicate that yellow earth is not the early stage in development of and earth,but has its own genetic characteristics.Humid climate,better permeability of weathering materials are all the condition favorable for the formation of yellow earth.