An assessment of subsoil organic carbon stocks in England and Wales

It is estimated that half the soil carbon globally is in the subsoil, but data are scarce. We updated estimates of subsoil organic carbon (OC) in England and Wales made by Bradley etal. (2005) using soil and land-use databases and compared the results with other published data. We estimated that the soils of England and Wales contained 1633, 1143 and 506Tg of OC at 0-30, 30-100 and 100-150cm depths, respectively. Thus, half of the soil OC was found below 30cm depth. Peat soils accounted for the largest proportion, containing 44% of all the OC below 30cm despite their small areal extent, followed by brown soils, surface-water gley soils, ground-water gley soils and podzolic soils. Peat soils had more than 25% of their profile OC per unit area in the 100-150cm depth, whereas most other soils had