Field Indicators of Hydric Soils in the United States - ITC

Field Indicators of Hydric SoilsSpodic horizon. A mineral soil horizon that is characterizedby the illuvial accumulation of amorphousmaterials composed of aluminum andorganic carbon with or without iron. The spodichorizon has a certain minimum thickness andminimum quantity of oxalate extractable carbonplus aluminum or specific color requirements,or both.Umbric Epipedon. A thick, dark mineral surfacehorizon that has base saturation of less than 50percent. See USDA, NRCS, Soil Taxonomy(1999) for complete definition.Vertisol. A mineral soil with 30 percent or moreclay in all layers. This soil expands and shrinksdepending on moisture content and containsslickensides or wedge-shaped peds. See USDA,NRCS, Soil Taxonomy (1999) for completedefinition.Wetland. An area that has hydrophytic vegetation,hydric soils, and wetland hydrology, per the FSAManual and the U.S. Corps of Engineers, 1987Wetlands Delineation Manual (fig. 41).Within. When referring to specific indicator depthrequirements, within means not beyond indepth, for example, less than or equal to 15 cm.Figure 41. If the area this soil represents has hydrophyticvegetation and wetland hydrology, it would be awetland. This soil has the Indicator F2 LoamyGleyed Matrix.30 (430, FIHS, Ver. 5.01, March 2003)