AAD.Hemistels

Key to Great Groups 

AAD. Other Histels that have more thickness of hemic soil materials than any other kind of organic soil material to a depth of 50 cm or to a densic, lithic, or paralithic contact, whichever is shallowest. Hemistels, p. 450 

AAD. These are wet Histels in which the organic materials are moderately decomposed. The botanical origin of much of the organic material is between one-sixth and two-thirds after rubbing between the fingers. Water is at or very close to the surface of these soils much of the time, unless artificial drainage has been provided. The level of ground water may fluctuate but seldom drops much below the surface tier. Hemistels occur in depressional areas or the adjacent water bodies. These soils are known to occur in Siberia, Canada, and Alaska. 

Definition 

Hemistels are the Histels that:

1. Are saturated with water for 30 or more cumulative days during normal years (and are not artificially drained);

2. Do not have a glacic layer that has its upper boundary within 100 cm of the soil surface; and

3. Have more thickness of hemic soil materials than any other kind of organic soil material to a depth of 50 cm or to a densic, lithic, or paralithic contact, whichever is shallowest. 

Key to Subgroups 

AADA. Hemistels that have a lithic contact within 100 cm of the soil surface. Lithic Hemistels 

AADB. Other Hemistels that have a mineral layer 30 cm or more thick within 100 cm of the soil surface. Terric Hemistels 

AADC. Other Hemistels that have, within the organic materials, either one mineral layer 5 cm or more thick or two or more layers of any thickness within 100 cm of the soil surface. Fluvaquentic Hemistels 

AADD. Other Hemistels. Typic Hemistels 

Definition of Typic Hemistels 

Typic Hemistels are the Hemistels that:

1. Do not have a lithic contact within 100 cm of the soil surface;

2. Do not have a mineral layer between 5 and 30 cm thick or two or more thin, continuous mineral layers within 100 cm of the soil surface; and

3. Do not have a mineral layer 30 cm or more thick that has its upper boundary within 100 cm of the soil surface.

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