Soil carbon stocks in ecoregions of Africa

Abstract

The African continent plays a growing role in the carbon (C) cycle. However, Africa is one of the weakest links in our understanding of the global carbon cycle particu- larly when considering the soil compartment. Most of the soil organic carbon (SOC) 5 estimates concern the global size of the soil C reservoir without indication on its distri- bution, or if given, limited to the contribution of a large ecosystems or region. The aim of the study is i) to assess the original soil C stocks (SOC) of Africa for the different countries and Ecoregions, and ii) to compare SOC estimates from different soil properties databases and digital maps. Four recent global digital soil maps and five soil 10 properties databases were used to estimate the SOC for different soil layers in Africa. Those databases hold between 1799 and 4043 soil profiles which are considered to represent the soil units showed on a 0.5 by 0.5 degree soil maps of Africa. SOC of Africa ranged 133 420184 116Tg for 0100cm soil layer. The most recent databases estimated 166 397Tg C which corresponded to 9% of the global SOC stock 15 and 68% of the terrestrial C pool of Africa. Average SOC ranges 0.48.2 kgm2 at national scale and 1.536.61 kgm2 for ecoregions. Using different soil database or spatial data leads to up to 30% of difference. These quantities indicate a great potential to develop sink activities through soil C sequestration activities.