Composition and Cycling of Organic Carbon in Soil

Abstract

Soil organic carbon (SOC) represents a significant reservoir of carbon within the global carbon cycle that has been estimatedto account for 1,200–1,550 Pg C to a depth of 1 m and for 2370–2450 Pg C to a depth of 2 m (Eswaran et al. 1995; Lal 2004a).Comparative estimates of organic C contained in living biomass (560 Pg) and atmospheric CO2-C (760 Pg) (Lal 2004a) indicate that variations in the size of the SOC store could significantly alter atmospheric CO2-C concentrations. A 5% shift in the amount of SOC stored in the 0–2 m soil profile has the potential to alter atmosphericCO2-C by up to 16%.