Research on the property of soil geochemistry in typical karst area in Guizhou Province

The main research object of this paper is the soil samples from three sampling sites - Dangwu in Huaxi, Xiazi in Zunyi and Muza in Anlong, in Guizhou Province. The relevant element content and the features in migration process from the rock to soil as well as the laterite-forming capacity coefficient are studied from the point of geochemistry, which shows the synthetic agro-geologic properties in the study area. Furthermore, preliminary evaluation is made on the environmental quality of the mineral nutrient elements in the paper. The results prove that leaching of mineral nutrient elements in limestone is comparatively strong with about 10 kinds of elements lower than the mid-value in China or the world, and the mineral nutrient element content is lower in the soil developed from pure limestone in particular. But the mineral nutrient element content in Anlong is higher than the other two sites for two reasons, first，the parent rock being dolomitic limestone and second, the position of Anlong being easy to collect the elements leached out from the nearby areas. The rate of reaching standard of nutrient elements is 73.7% (Muza in Anlong),63.1%( Xiazi in Zunyi) and 68.4% (Dangwu in Huaxi). Generally speaking, for the slow pedogenesis of carbonatite, the soil layer developed from carbonatite is thin with low nutrient content, so the soil needs being fertilized by some mineral fertilizers.