Study on the Slope Vegetation-SoiI Environmental Change in Shanxia Reservoir Area and Its Land Utilization

The slope vegetation succession in Shanxia Reservoir Area has been changed from the subtropical evergreen forest to the natural coppice forest,barren herb slope and plantations. Its forest coverage decreased from 45.5% in 1940 to 21.7% in 1985 and the forests distributed unevenly,shaping like island,speckles and blocks. The deterioration of the slope vegetation led to the unfertile soil characteristics:content of stone particles in the soil is 6%～30%;thickness of soil layer 40～60 cm;texture of soil soft.During·the heavy raining season (April～October),soil erosion is serious. Besides,the irrational land exploitation in this area intensified the soil erosion. To bring the change of the slope vegetation and environment under control,the technology of planting bio-living-fence and agroforestrywas adopted.The method is using the tree species,which are fast-growing,easy-sprouting and good at fixing N for contour line planting to prevent the slope from further erosion. The plant species selected are:Robinia pseudoacacia,Vitex negundo,Coriaria sinica,Leucacena leucocephala,Amorpha fruticasa,Vetiveria nigritana,Carex spp.,arbor,shrub and herb species. 3 years after the cultivation he forest coverage increased to 35% and the content of mud and sand in the running water from the slope was 3.3g/m2,while that on the land without vegetation was 37.97 g/m2.