| histic epipedon | An 8- to 16-inch soil layer at or near the surface that is saturated for 30 consecutive days or more during the growing season in most years and contains a minimum of 20 percent organic matter when no clay is present or a minimum of 30 percent organic matter when 60 percent or more clay is present, generally a thin horizon of peat or muck if the soil has not been plowed. (09 Oct 1997) |
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