Effects Of Influence Factors On The Rate Of Soil Formation In Karst

The area of karst region in China is 3,440,000km2, which is about 1/3 of land area. Among that the bare karst mountainous region is about 90.7 km2. Southwest China karst region where Guizhou Province is the core appears the problem of karst rocky desertification as one of four major ecological disasters which make the area become the most difficult remediation and getting rid of poverty area. It is because that very vulnerable and sensitive geological environment, dual pressures of over population and economic and social backwardness and eco-environmental degradation caused by historical reason. Soil erosion is the direct reason of rocky desertification, but in the karst region the research of it is more lag. The research is about the natural and man-made factors on the dissolution rate of soil formation in different land use patterns that the concretely study is the soil quality difference caused by human activity, and lucubrate dissolution soil formation rate of different land use pattern. The research has important scientific significance and applied prospects on exploring the process of soil erosion, study on karst effect, the reasonable use and protection of soil resource in karst region, soil erosion control and rock-desertification governance and the economic development of the karst rural area.The research area of this paper locates in karst region of Zhongliang Mountain in Chongqing. The dissolution rate under different land use patterns (wood land, grassland, orchard land, vegetable land and arable land) which is obtained by the solution tablets and acid-insoluble content of the strata in the research region canobtain the rate of soil formation. Through different times and under different land-use patterns compare the dissolution rate of the tablets, combined with the study area during the experiment staining of meteorological data and soil water movement under simulated conditions, probe the influence of the soil formation of different land use patterns and season, precipitation factors on the dissolution rate.The research proves that the land use pattern can obviously influence the properties of soil. Compared to two years solution rate of tablets which under different land use patterns, except to the 5cm and 20cm of arable land, the solution rate of tablets in 2007-2008 are larger than the dissolution rate in 2009-2010. And compared the same soil-layer profile with different dissolution rate change trend in two years, arable land and vegetable land are more consistent trends, grassland and woodland and orchard land are in similar trends. Contrast the average dissolution rate of different land use patterns in the two years, the result is wood land> grassland> vegetable land>arable land> orchard land. In addition, the absolute dissolution of the specimens in 2009-2010 year are less than the dissolution in 2007-2008 year, indicating that soil-forming material may be slightly decreased. And the dissolution of 5cm under different land use patterns difference between two years are small, this difference increases with the depth, but the range of difference decreased.The rainy season dissolution of the tablets contribution is large.The rainy season share of the absolute amount of the whole year absolute dissolution ratio of the amount more than 50%; and 0-20cm in soil profiles is the most significant. In the rainy season, high temperature and soil moisture content are more conducive to the conduct of karst. Thus indicating that temperature, rainfall is the important factors of dissolution process. With compared the dissolution rate of rainy season and the whole year, it found that temperature and rainfall are the important factors in the dissolution process and the dissolution contribution rate of rainy season is bigger. Land use pattern will influence dissolution rate by influence soil physicochemical property. Karst action is jointly influenced by the reciprocity of soil pH, organic carbon, soil moisture content and extent of porosity, and the underground karst dissolution is the comprehensive function of multi-factor and reciprocity of them.The wood land soil properties and corrosion resistance are better and it is propitious to continuously thickening soil layer in karst region. Increasing forest coverage rate of karst region has major significance.