ABSTRACT
Soils contain about three times the amount of carbon (C) as the atmosphere, and vegetation contains a slightly smaller amount than the atmosphere. Land management has a large impact on soil and vegetation carbon levels and converting forest land or grassland to croplands has caused significant loss of terrestrial carbon. Historically, soils have lost between 40 and 90 Pg (1 Pg = 1 Gt = 1015 g = thousand million tonnes) C globally through cultivation and disturbance, with total historical losses (including vegetation) of 180 Pg C. Biological carbon sequestration is the process whereby land use and land management are used to restore soil and vegetation carbon stocks.
