AuthorsMizoguchi, Y., Ohtani, Y., Watanabe, T.
TitleInfluence of Soil Temperature and Moisture on Forest Floor CO2 Efflux -Clarification of the Effect of Soil Moisture using Field Data-
JournalJournal of agricultural meteorology
KeywordsCO2 efflux from a forest floor, CO2 production, diffusion, soil moisture, soil temperature
AbstractBoth soil temperature and water content are important environmental factors in determining CO2 efflux from a forest floor. To analyze the effects of soil temperature and water content on soil CO2 efflux based on field data, these elements were measured in a temperate deciduous forest. CO2 concentration, air porosity, volumetric water content, the diffusion coefficient and CO2 production rate were also measured. CO2 efflux was separated into CO2 transfer and CO2 production processes using the diffusion coefficient, CO2 concentration and CO2 production rate data. Both the CO2 transfer and CO2 production rates increasing soil temperature. The CO2 transfer rate decreased when the difference between CO2 concentration at surface and that in soil was nearly constant and the CO2 production rate increased with increasing soil moisture. On the other hand, the CO2 efflux, which represents the sum of the CO2 transfer rate and CO2production rate, might increase with increasing soil moisture, when the difference in CO2 concentration is small and consequently the decreasing rate of CO2 transfer is low. To clarify the soil moisture effects on forest floor CO2 efflux, separation of CO2 transfer and CO2 production processes is more effective than direct parameterization of CO2 efflux by soil moisture.