Research On Soil Anti-erosion Of Main Plant Communities In Siman Mountain, Chongqing

Because of special natural environment and human activities, there are many ecological and environmental problems in Chongqing (Three Gorges Reservoir Area), such as soil and water loss, geological disasters. Although ecological construction has been promoted by our country and government, many problems exist, especially for the vegetation construction. Simian Mountain is located in the end of Three Gorges area. It has rich natural resources, however, the development of tourism resource, cutting, grazing and reclaiming of peasants, has let lots of trees be damaged, and made severe soil and water loss. This area has become the main source of sediment to the three Gorges Reservoir area. So research on soil anti-erosion in this area of different plant communities is significant for soil erosion control and vegetation construction in the Three Gorges Reservoir area.Associated with the national eleventh-five year plan of state key task of scientific and technological research "Technology Research and Demonstration of Vegetation Construction with Soil and Water conservation in Three Gorges Reservoir Area, Yangtse River Basin ", based on the experiments of dispersion of soil particals in water, scourry and analysis of soil physical and chemical characteristics, this study analyzed the soil anti-erosion characteristics and its influenceing factors of the main plant communities in Simian mountain. The main conclusions are as follows:(1)The soil anti-erosion characteristics are obvious different in different plant communities. Evergreen and deciduous forest community soil has the best soil anti-erodibility (85.0%), and the soil anti-erodibility of warm bamboo groves is the worst (62.0%). Warm bamboo groves soil has the best anti-scouribility (28.94 L-min/g), and the soil anti-scouribility of hurmoral coniferous forests is the worst (5.56 L·min/g). The soil anti-erodibility decreases with the increase the duration of rainfall. The soil anti-scouribility is exponentially correlated to time. The soil anti-erodibility and soil anti-scouribility decreases with depth.(2) Physical and chemical soil characteristics play a difference role in the soil anti-erosion characteristics of different plant communities. Soil anti-erodibility is linearly correlated to non-capillary pores(X3), content of rough sand(X5,2-1mm) and powdery(X10,0.05-0.002mm). The equation is as following: S=104.785+1.279X3-5.428X5-1.849X10 It is also linearly correlated to the content of total phosphorus(X14) and rapid available potassium(X17). The equation is:S=10.480+7.671X14-1.067X17Soil anti-scouribility is linearly related to the soil density(X1), the content of medium sand(X7,0.5-0.25mm), the small sand(X8,0.25-0.05mm), powdery(X10,0.05-0.002mm), and clay(X11,<0.002 mm). The equation is: C=-62.830-12.824X1+2.928X7+0.649X8+2.182X,0+0.822X11 It is also linearly correlated to the organic matter content (X12). Tts equation is:C=-2.572+0.291X12(3) Soil anti-erodibility has a close relationship with anti-scouribility of plant communities. The soil anti-erosion capacity of different plant communities were evaluated by comprehensive coordinate method, and the order is as follows:warm bamboo groves (0.109), evergreen broad-leaved forest (0.448), deciduous broad-leaved forest (0.585), evergreen and deciduous forest community (0.618), hurmoral coniferous forests (0.732), warm coniferous forests (0.626).