Quantifying CO2 fluxes from soil surfaces to the atmosphere

摘要: Abstract Measurements of CO 2 fluxes from ground surface the atmosphere (soil respiration) are needed to quantify biotic and abiotic reaction rates in unsaturated zones gain insight into importance these processes on global warming. The use three techniques (dynamic closed chambers, static gradient calculations) determine soil respiration was assessed by measuring microbially produced an mesocosm (2.4 m dia.×3.2 m thick) two minicosms (0.58 m dia.×1.2 m thick), one maintained at 18–23 °C (HT) other 5 °C (LT). By injecting known constant bottom HT minicosm resulting fluxes, it shown that dynamic chamber (DCCS) technique yielded accurate measurements over range observed natural media. Over this same range, results showed concentration method reasonable estimates but its accuracy limited uncertainties both gaseous diffusion coefficient atmosphere. underestimated actual flux higher when adsorption times >24 h were used.