Major anthropogenic greenhouse gases emissions namely carbon dioxide (CO₂) and methane (CH₄) emissions originate from the biodegradation of soil organic carbon (SOC). Thus, CO₂ and CH₄ emissions strongly respond to changes in soil temperature and moisture and consequently to climate. Even though CO₂ and CH₄ monitoring are common today, key mechanisms controlled by these drivers are little known rendering their representation in land surface model (LSM) and Earth system model (ESM) doubtful and increasing model results uncertainties. My research efforts aim at improving the representation in LSM and ESM of SOC biodegradation and to enhance our understanding of soil physico-chemical properties and SOC interactions. Results on the influence of soil moisture on heterotrophic respiration and reactiveness of methanogenesis and CH₄ transport processes in the LSM ORCHIDEE will be presented as well as near future research directions.