of soil organic carbon (SOC) are based on surficial measurements
to depths of 0.3 to 1 m. But many of the world’s soils greatly exceed 1 m
depth. This paper provides the
first detailed analysis of these previously unreported stores of SOC.Soils from five
sites in south-western Australia were analysed for SOC. These soils ranged between 5 and
38 m depth to bedrock. Mean SOC for each of the five locations varied from 21.8–37.5 kg C m−2, two to five times greater than from sampling to a depth of just 0.5 m.
This finding may
have major implications for estimates of global carbon storage and
modelling of the impacts of climate change. The paper demonstrates the need for a
reassessment of the current shallow soil sampling depths for
assessing carbon stocks and a revision of global SOC estimates.