Digital Soil Mapping: A State of the Art

Digital Soil Mapping (DSM) can be defined as the creation and population of spatial soil information systems by numerical models inferring the spatial and temporal variations of soil types and soil properties from soil observation and knowledge and from related environmental variables. DSM is now moving toward the operational production of soil maps thanks to a set of researches that have been carried out for the last fifteen years. These researches dealt with various topics: the production and processing of soil covariates, the collection of soil data, the development of numerical models of soil prediction, the evaluation of the quality of digital soil maps and the representation of digital soil maps. The recent advances and open questions within each of these topics are successively examined.

The emergence of DSM as a credible alternative to fulfill the increasing worldwide demand in spatial soil data is conditioned to its ability to (i) increase spatial resolutions and enlarge extents and (ii) deliver a relevant information. The former challenge requires to develop a specific spatial data infrastructure for Digital Soil Mapping, to grasp Digital Soil Mapping onto existing soil survey programs and to develop soil spatial inference systems. The latter challenge requires to map soil function and threats (and not only “primary” soil properties), to develop a framework for the accuracy assessment of DSM products and to introduce the time dimension.