Relationship of soil surface CO2 flux with microbial biomass carbon in the karst areas of Southwest China

THE production of C0in the soil results from the oxidation of soil organic matter by heterotrophic microorganisms and by the respiration of plant roots. The release of C0from the soil is a major flux in theglobal carbon cycle, which is largely fuelled by plant production. In this note, we investigated the release of C0from soils of the karst region. We measured the amount of soil microbial biomass carbon,soluble organic carbon in the soil, and the flux of C0from the soil surface over a 1-year period. Thisnote is to examine the factors affecting the flux of C0from the soil surface in an ecosystem with nutrientpoor soils and limited amounts of soil microbial biomass. This study was conducted from June 1997 through May 1998 on a hill side, located in the suburbs ofGuiyang City in Guizhou Province of China (latitude 26°30’N, longitude 106°39’E). Situated 1 140m