Studies On Soil Degredation Mechanism Of Dolomite Area

Degeneration problems of karst soil are mostly infertile soil, vegetation reduction, natural environment erosion and rock desertification. When the karst entironment is unreasonable utilized and leads to obsolescence once, the problem is more grave and it is difficult to manage and renew because of its fragility particularity. Researches on soil degradation of karst soil are emphasized on limestone soil. Now there is no researches on soil degradation of dolomite soil. This paper had discussed the impact of different land use patterns on soil physical and chemical properties. To study the processes, characteristics and mechanism of dolomite land, make contribution to understanding the mechanism of Karst ecosystem, and provide theoretical guidelines for the restoration and reconstruction of degraded karst ecosystem and the optimizing of land utilization structure. The results show that:1. Soil of dolomite areas in Guiyang is thin , soil component are mainly thick and thin sand ,and there was not mucosity characteristic, soil structure is better. High total porosity ,high gravel content .Land use patterns had significantly influences on soil physical properties, The total porosity and soil water-holding capacity would became lower , the soil bulk density and particle density would became higher as the soil utilized more grievously. Soil physical properties has regional differences under same land patterns, which related to ecological indexes and humankind actions. Low bulk density , high total porosity, high capillary porosity will be high soil capillary capacity and soil moisture capacity., Conversely, the result is contrary. Land utilized unreasonablely, vegetation cover-rate, vegetation type would influence on soil physical properties, Renewness of shrub has great influences on the improvement of soil physical properties.2. The results show that soil organism content, N Content, P Content, K Content are lower as the increasing in strength of land-use. Land use patterns had significantly influences on soil chemical properties, organism content related to vegetation type, soil thickness, gravel content, elevation and climate. Organism content of conifer forest land , broadleaf forest land , shrub land sequentially are broadleaf forest land>...