GlobalSoilMap : toward a fine-resolution global grid of soil properties
Résumé
Soil scientists are being challenged to provide assessments of soil condition from local through to global scales. A particular issue is the need for estimates of the stores and fluxes in soils of water, carbon, nutrients, and solutes. This review outlines progress in the development and testing of GlobalSoilMap a digital soil map that aims to provide a fine-esolution global grid of soil functional properties with estimates of their associated uncertainties. A range of methods can be used to generate the fine-resolution spatial estimates depending on the availability of existing soil surveys, environmental data, and point observations. The system has an explicit geometry for estimating point and block estimates of soil properties continuously down the soil profile. This geometry is necessary to ensure mass balance when stores and fluxes are computed. It also overcomes some limitations with existing systems for characterizing soil variation with depth. GlobalSoilMap has been designed to enable delivery of soil data via Web services. This review provides an overview of the system's technical specifications including the minimum data set. Examples from contrasting countries and environments are then presented to demonstrate the robustness of the technical specifications. GlobalSoilMap provides the means for supplying soil information in a format and resolution compatible with other fundamental data sets from remote sensing, terrain analysis, and other systems for mapping, monitoring, and forecasting biophysical processes. The initial research phase of the core project is nearing completion and attention is now shifting toward establishing the institutional and governance arrangements necessary to complete a full global coverage and maintaining the operational version of the GlobalSoilMap. This will be a grand and rewarding challenge for the soil science profession in the coming years.