Soil organic carbon (SOC)
Definition
The carbon pool that includes all organic material in soil, but excluding the coarse roots of the belowground biomass pool.
Source
Glossary. M.S. Ashton et al. (eds.), Managing Forest Carbon in a Changing Climate, DOI 10.1007/978-94-007-2232-3, © Springer Science + Business Media B.V. 2012
Alternative definition
It refers to the carbon held within the soil and is expressed as a percentage by weight (gC/Kg soil).
Alternative source
Natural Resources Management and Environment Department, NR, FAO, 2009.