Features of Soil and Water Loss and Key Issues in Demonstration Areas for Combating Karst Rocky Desertification
Very little information on water and soil loss in karst areas is available. Moreover, traditional methods of assessing soil loss are difficult to apply to this area. In this paper the authors analyze the features of water and soil loss based on location monitoring during the five years (2006-2010), in demonstration areas for combating karst rocky desertification (KRD). The following conclusions are obtained. (1) Soil erosion showed a decreasing trend after a series of comprehensive treatments in the three study regions, and erosion was macroscopically mitigated in terms of landform types. (2) The slope cropland is distributed extensively in Yachi mountain region and erosion is thus serious. With better natural conditions and ecological economy development, erosion in Hongfenghu basin is relatively weak. Due to the severely poor soil cover, the amount of soil erosion is extremely low in Huajiang gorge. (3) Ecologic rehabilitation is the key to combat KRD. Closing hillsides to facilitate afforestation and water conservation are effective measures for the mitigation of soil and water loss. Grassland and economic forests bring both economic and ecological benefits. (4) KRD degrees differ greatly in slope gradient and soil layer. Further classification for soil erosion in karst areas should be proposed based on KRD degrees. (5) Hazard evaluation of subterranean soil loss is one of the tough tasks at present. However, control of key parts such as sinkholes is the efficient way to prevent subterranean loss.