Diagnostic Subsurface Horizons

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Cambic horizon - A cambic horizon is the result of physical alterations, chemical transformations, or removals or of a combination of two or more of these processes.

Required Characteristics

The cambic horizon is an altered horizon 15 cm or more thick. If it is composed of lamellae, the combined thickness of the lamellae must be 15 cm or more. In addition, the cambic horizon must meet all of the following:

  1. Has a texture of very fine sand, loamy very fine sand, or finer; and

  2. Shows evidence of alteration in one of the following forms:

    1. Aquic conditions within 50 cm of the soil surface or artificial drainage and all of the following:

      1. Soil structure or the absence of rock structure in more than one-half of the volume; and

      2. Colors that do not change on exposure to air;
        and

      3. Dominant color, moist, on faces of peds or in the matrix as follows:

        1. Value of 3 or less and chroma of 0; or

        2. Value of 4 or more and chroma of 1 or less; or

        3. Any value, chroma of 2 or less, and redox concentrations; or

    2. Does not have the combination of aquic conditions within 50 cm of the soil surface or artificial drainage and colors, moist, as defined in item 2-a-(3) above, and has soil structure or the absence of rock structure in more than one-half of the volume and one or more of the following properties:

      1. Higher chroma, higher value, redder hue, or higher clay content than the underlying horizon or an overlying horizon; or

      2. Evidence of the removal of carbonates or gypsum; and

  3. Has properties that do not meet the requirements for an anthropic, histic, folistic, melanic, mollic, plaggen, or umbric epipedon, a duripan or fragipan, or an argillic, calcic, gypsic, natric, oxic, petrocalcic, petrogypsic, placic, or spodic horizon; and

  4. Is not part of an Ap horizon, is not appreciably darkened (does not meet the color requirements for a mollic or umbric epipedon), and is not brittle.

Keys to Soil Taxonomy, Eighth Edition