It is generally recognized that soils represent a major pool in the global C-cycle, as they contain more organic carbon than the atmosphere and biosphere together. As soil organic carbon (SOC) is a dynamic soil property, monitoring SOC is crucial in the framework of international treaties facing climate change (e.g. Kyoto protocol) and directives considering soil quality (e.g. EU Soil Thematic Strategy). More accurate SOC estimates at the regional scale are essential to better understand the significance of the soil reservoir. As detailed SOC maps and an insight into the effects of physical (i.e. soil type and climate conditions) and anthropogenic factors (i.e. land use and land management) on SOC storage are not fully understood yet, this study unraveled the influence of environmental factors on SOC inventories, its distribution with depth, and its change through time. Therefore a new SOC mapping technique, an empirical model-based approach, was developed and allowed the estimation of reliable SOC values for a wide range of landscape units, resulting in complete and spatially detailed SOC maps for Belgium. This method also allowed studying SOC stock changes between 1960 and 2006. The integration of depth as a third dimension in the present spatial - temporal explicit approach provided information on the stability of C and offered the possibility to map SOC until a reference depth free of choice. The results revealed that to a large extent SOC is determined by land use, precipitation, drainage status and clay content. By modelling the vertical SOC distribution and establishing pedotransfer functions (PTF’s), predicting the parameters of this vertical distribution in function of environmental variables, SOC could be modelled in a 3D context. The results show that the influence of land use on SOC is restricted to the topsoil, while soil type determines the vertical SOC distribution. The application of the new SOC mapping technique in a temporal context shows that in total, SOC stock in top 0.3 m increased with ...