Digital Soil Mapping (DSM)
Digital soil mapping (DSM) represents “the creation and population of spatial soil information systems by the use of field and laboratory observational methods coupled with spatial and non-spatial soil inference systems” (Lagacherie and McBratney, 2007). Soil science, geographic information science, quantitative methods (statistics and geostatistics) and cartography are combined within the DSM framework. DSM methods are used to estimate the spatial distribution of soil classes (e.g., soil series) and/or soil properties (e.g., soil organic matter), and can be employed at various scales (from individual fields to countries), and have proven valuable for developing more quantitative, more accurate, and more precise soil maps.
The NSSC-GRU has identified DSM as an important area of focus in support of soil survey activities. NumerousDSM research projects have been supported by the GRU. Numerical classification (hierarchical and fuzzy), spatial and temporal interpolation (geostatistics, wavelets), sampling design (model vs. design based), statistical analysis (visualization, ordination, regression, and classification), uncertainty analysis (error propagation, accuracy assessment), and incorporation of auxillary data (proximal and remotely sensed imagery, soil-terrain modeling) are among the methods used to develop predictive maps of soil classes and soil properties.
The GlobalSoilMap.net project is committed to producing digital soil property maps of the land surface of the Earth. The soil properties of interest include soil organic carbon content, pH and particle size fractions (sand, silt, clay, coarse fragments). Such maps will be useful tools for agriculture, land management and planning, and global change studies. The Geospatial Research Unit is involved in the production of the digital soil maps for North America in collaboration with colleagues from the National Soil Survey Center of the USDA’s Natural Resources Conservation Service (USDA-NRCS-NSSC) in Lincoln, Nebraska, and Agriculture and Agri-Food Canada (AAFC).