Study on Soil CO2 Concentration and Surface CO2Flux in Karst Rocky Desertification Area

【Objective】 This paper aimed to investigate the distribution of CO2 concentration and its temporal and spatial emission laws in karst rocky desertification areas in southern China, and to explore the effects of environmental factors such as soil organic carbon content, soil temperature and soil water content on CO2 concentration and release rate in karst areas. 【Method】 The Static sealed chamber-gas chromatography method was used to monitor in situ the soil CO2 concentration and the surface CO2 flux in the terraced karst carbon sink experimental area and in the non-terraced karst carbon sink control area respectively in Nanchuan Rocky Desertification Control Demonstration Area in Chongqing from January to December of 2017. 【Result】 The soil CO2 concentration in the non-terraced area was higher than that in the terraced area, and the soil CO2 concentration in terraced area and non-terraced area decreased with the increase of soil depth; the surface CO2 emission flux in non-terraced area was higher than that in terraced area; both the soil CO2 concentration and the emission flux changed significantly with seasons. The soil temperature and soil water content showed significant positive correlations with the surface CO2 emission flux to some extent, and obvious changes occurred in some months, shown as huge sources and sinks. 【Conclusion】 Soil CO2 concentration is jointly affected by soil organic carbon, soil temperature, soil water content, soil microorganisms and human factors while the surface CO2 flux is closely related to vegetation coverage, human activities and soil CO2 concentration.