These simple calculations do not include the likely residence time of the carbon stored in the biomass and soil pools. One possible method to address this is to consider above- and below-ground carbon storage in terms of “carbon-years”: the change in carbon multiplied by the mean residence time of each pool. This would allow the value of carbon stocks in different pools to be compared more equitably. Of course this approach would require both characterisation of biomass and soil carbon pools, and the likely residence time of C within them, neither of which is simple.
4.4. Methods of reporting SOC stocks and statistical power
This experiment attempted to determine if there was a change in SOC to a depth of 150 cm. In principle it is important to establish if there is change at such depths as 30% of the organic carbon in the 150 cm profile was found at depths > 60 cm. However as found in meta-analyses, for example by Shi et al. (2013), we were unable to determine a statistically significant change in SOC stock below 40 cm.