Organic Carbon Content And Carbon Isotope Composition Of Soil From Typical Terrestrial Ecosystem Of Guizhou Province

Rock desertification of Karst Mountains centered upon Guizhou province in southwest China and desertization in northwest China are the two fundamental regional environmental problems in the process of carrying out the strategy for great development of west China. It is now recognized that rock desertification is a process of land degradation resulting from the comprehensive action due to the overprint of irrational anthropological activities on the karst fragile eco-geo-environment background, and soil degradation is the core of land degradation. Soil degradation is a kind of phenomenon and a process of accelerated decline of soil quality and productivity because of human's improper exploitation and utilization and it indicates a decline in soil fertility and productivity for agriculture and a decline in soil quality for environment. Compared with the non-karst areas, soil and vegetation in the karst areas are the impressionable natural environmental elements and have an obviously weak characteristic (Such as thinner soil layer, narrower soil loss tolerance, less suitable tree species, simpler community structure and lower biomass, etc.). Under the interference of anthropological activities, they have experienced a quick decline of vegetation coverage, severe water and soil loss and erosion near to bedrock, as a result the rock desertification is formed. In the process of soil degradation and global carbon cycle, as an important composition of soil and a major carbon pool of the terrestrial carbon reserves, soil organic matter plays a key role in ecosystem. The study of the stable carbon isotope composition of vegetation and soil organic matter in karst areas is the basic task to understand the biogeochemistry cycle in this region.Taking non-karst areas as comparison, this research selects the typical karst areas in Guizhou province as study sites. The stable carbon isotope composition of plant dominant species, litter, soil organic matter in bulk soil and particle-size fractions in soil profiles under different vegetable forms and soil types are analyzed, and the soil organic carbon contents, pH values and particle-size composition are measured. This study aims at improving the understanding of the origin, decomposition and transformation of soil organic matter and the regional carbon pool character through the research of stable carbon isotope composition of soil organic matter in Guizhou...