The erodibility of a soil is determined by the material textural properties, such as particle size, structure and cohesion. The magnitude of erosive forces is determined by the quantity of surface runoff and its associated energy, which are related to precipitation and slope characteristics. Many polygons on soil maps contain complexes of two or three soil associations.
Most soils maps have accompanying reports which describe the soil associations in detail.
Included in these reports are interpretations of the erodibility of the soil associations in the event of soil surface disturbance. Erodibility is assigned to soils in erodibility groups based on slope. Moderate - Moderate likelihood of erosion. High or severe - High likelihood of erosion. In some cases, soils maps may not be accompanied by reports in which soils associations and potential erodibility are defined.