Pedons

Pedons are fundamental units in pedology—the study of soils. A pedon is the smallest three-dimensional body of soil that contains the full set of diagnostic horizons and the variability characteristic of a particular soil type. It is large enough to include the complete horizon sequence (such as O, A, E, B, C where present) and the features that distinguish the soil, yet small enough to be studied in detail in the field. In practice, pedons are described and sampled in the field to create a representative basis for soil description, classification, and mapping. When a landscape contains substantial variability, several pedons (a poly pedon) are sampled to capture within-site variation; a single pedon (monopodial) may be used for more uniform areas.

Within a pedon, soil scientists describe the vertical profile and spatial variability, noting horizon boundaries, color, texture, structure, porosity, density, moisture regime, pH, organic matter, salinity, carbonate content, and other properties. The term pedon is distinct from a soil profile: a profile is the vertical section through the soil, while the pedon is the three-dimensional sample used to represent the soil in a given area.

Pedons underpin soil surveys, pedon naming, and classification systems and are used to interpret land use, fertility, drainage, and management implications.