In Situ Monitoring of Soil Carbon Fluxes for Different Typical Soils in Karst Region of Southwest China

Two karst soils(terra fusca and rendzina)and a contrast soil(red soil)were selected to study soil carbon fluxes in typical karst soils.The daily and seasonal soil carbon fluxes on different interfaces(soil surface and soil stone surface)were tested to indicate the transformation of soil organic carbon.Results shows that soil carbon flux in rainy season was higher than that in dry season.Soil carbon flux in red soil was steadier than that in terra fusca of both shrub land and forest land.Soil carbon flux in terra fusca was more sensitive to temperature and humidity than that in red soil.Soil carbon fluxes in rendzina of shrub land(soil surface and soil stone surface)were less than that of forest land.Soil carbon flux in rendzina of forest land was higher than that of the shrub land.The maximum values of soil carbon flux on soil surface occurred in July(3.0 μmol m2/s)in both the shrub land and forest land,while on soil stone surface,in June(1.5μmol m2/s).In shrub land,the maximum value of soil carbon flux on soil stone surface occurred in June(1.9μmol m2/s).This implied that soil carbon flux differed in soil types in karst area.Climate,season and vegetation were the most important factors which influence soil carbon flux in karst area.Soil carbon fluxes of soil surface and soil stone surface were greatly impacted by them.