The amount of SOC stock at any given time is controlled by factors of soil formation. The soil forming factors are climate, topography, parent material, biota, time, and human activity (Amundson and Jenny, 1997).

Current stocks indicate the baseline SOC stock. Figure 1 indicates SOC stock for Africa (http://www.isric.org/data/soil-property-maps-africa-1-km).

Figure 1. Prediction maps of the lower limit, mean and upper limit (90% prediction interval) for organic carbon (permille) for the first standard depth (0-5 cm). White pixels indicate areas without any vegetation cover that have been masked out from the mapping.