The soil organic carbon (SOC) is a large carbon pool that could regulate the dynamic of carbon dioxide between the terrestrial. In the condition of rising concentrate of carbon dioxide (CO2), the capacity of carbons sequestering is the key to decipher the processes of carbon dynamics.Soil catbon residence time is defined here as how long the organic C can stay in the soil. Theoretically, the residence time (τ) of soil organic carbon is strongly correlated with climate conditions. In spite of difference between latitude, longitude and elevation, some previous studies indicated that temperature and precipitation are two dominant effective factors of carbon dynamics.
Our ability to predict future climate-carbon cycle feedback is strongly limited by our poor estimate of the residence time (τ) of soil organic carbon (SOC) and its covariation with environmental changes. Previous studies have used multiple observations and approaches to estimate the residence time (τ) of SOC at site level. However, it is unclear (1) whether results from these approaches are comparable or not; and (2) whether and how these observations can be combined for improving the estimate of SOC residence time at global scale. We used some datasets of incubation, pool-flux and stable isotope and radioisotope to study carbon residence time at the global scale.
Results/Conclusions
Preliminary results indicated that the residence time based on the different methods is variable. The SOC residence time based on incubation studies shows the smallest value with 13.9 ± 2 years, the largest value is 589 ±161 years from the pool-flux based method. The results based on the isotopes are 532 ± 51 years (δ13C) and 410 ± 69 years (Δ14C). Our results could help illustrate the estimated ranges of SOC residence time with different approaches. Further efforts are still needed to combine multiple observations to improve the global estimate of SOC residence time.