Guidelines for soil description
The Guidelines for Soil Description (SOIL_DESC) provide users with a complete procedure for soil description and for collecting field data necessary for soil classification systems, such as the World Reference Base (WRB). It is an upgraded version of the “FAO Guidelines for Soil Description “ published in 1990. The guidelines emphasize the use of standardized terminology and classes for all described soil characteristics. As such they assist with the collection of reliable soil morphological information and ensure worldwide comparability.
The process of soil description starts with entering registration information (observation number, author, date, description status) and information on the location (coordinates, elevation). The soil description status refers to the quality of the description and analytical data.
The following step is the description of the soil forming factors (climate, landform, parent material, land use/cover, vegetation, landscape age and history) in the area around the observation point.
This is followed by the actual description of a dug soil profile or auger observation. The first step here is the identification of boundaries, soil horizons and layers, description of surface characteristics (stones, rock outcrops, erosion/deposition, surface sealing), followed by the characterization of individual horizons or layers. This detailed soil horizon description terminology covers the following characteristics: soil color, mottling, texture, coarse fragments, structure, consistency, stickiness, plasticity, porosity, cutans, cementation, nodules, roots, biological activity, organic matter content, carbonates, gypsum, soluble salts, and soil reaction (pH). For all terms and classes used the equivalents in French, German and Spanish are available in the documentation of the software SDBm Plus.
The final section aims at assisting interpretation of the observed soil characteristics through soil classification. For this purpose it gives guidance on the agronomic significance of different soil horizons and subordinate characteristics and a primer in the use of the WRB for soil classification.