Soil science provides a comprehensive taxonomic classification for soils. This scientific classification is based on underlying geology, and the formation processes, composition, physical structure, and chemical properties of soils. Technical or interpretive classification systems consider specific land uses and management practices such as agricultural production, building development, and wildlife management. These are developed by experts in a specific field through interpretation of the comprehensive taxonomic system.

The scientific classification system used by the USDA National Cooperative Soil Survey has six hierarchical levels of taxonomic classification: order, suborder, great group, sub group, family, and series. A soil order, the most general level, contains soils that have similar processes and degrees of formation. A soil series, the finest level of description, comprises soils with similar composition and major soil horizons.

Map 2 from the Willamette River Basin Planning Atlas depicts soils based on an interpretive classification system designed to indicate the suitability of soils for agricultural crop production. This system assigns a land use capability classification from I to VIII (this is also known as soil capability classification). Figures 10 and 11 shows the percentage of these capability classes within the WRB and its 1995 urban growth boundaries. Class I soils present the fewest limitations and are the most suitable for agricultural crop production. As the capability classification number increases soil limitations increase and suitability for agricultural crop production decreases. Soil capability is further described with the addition of subclass and unit labels. The most complete description of a soil capability class is in the form IVe2. The Roman numeral indicates the degree of limitation, the lower case letter (subclass) describes the type of limitation (e- erosion potential, w- wet soil, s- shallow soil) and the Arabic number (unit) characterizes appropriate crops and management practices.