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BD.Hemists

Key to Suborders 

BD. Other Histosols. Hemists, p. 480 

BD. These are wet Histosols in which the organic materials are moderately decomposed. The botanic origin of much of the organic material cannot be readily determined. The fiber content of much of the organic material is between one-sixth and two-thirds after rubbing between the thumb and fingers. The bulk density commonly is between 0.1 and 0.2 g/cm3. Ground 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 bottom of the surface tier. Hemists occur from the Equator to latitudes with a cryic temperature regime. They are in closed depressions and in broad flat areas, such as coastal plains and outwash plains. Most Hemists are under natural vegetation and are used as woodland, rangeland, or wildlife habitat. Some large areas of Hemists are cleared, drained, and used as cropland. 

Definition 

Hemists are the Histosols that:

1. Are saturated with water for 30 or more cumulative days during normal years (unless artificially drained);

2. Do not have more thickness of fibric soil materials and do not have more thickness of sapric soil materials than any other kind of organic soil material either:

            a. In the organic parts of the subsurface tier if there is no continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier; or

            b. In the combined thickness of the organic parts of the surface and subsurface tiers if there is a continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier; or

3. Have a sulfuric horizon that has its upper boundary within 50 cm of the soil surface, or sulfidic materials within 100 cm of the soil surface, and more thickness of fibric soil material than any other kind of organic soil material either:

            a. In the organic parts of the subsurface tier if there is no continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier; or

            b. In the combined thickness of the organic parts of the surface and subsurface tiers if there is a continuous mineral layer 40 cm or more thick that has its upper boundary within the subsurface tier. 

Key to Great Groups 

BDA. Hemists that have a sulfuric horizon that has its upper boundary within 50 cm of the soil surface. Sulfohemists, p. 483 

BDB. Other Hemists that have sulfidic materials within 100 cm of the soil surface. Sulfihemists, p. 483 

BDC. Other Hemists that have a horizon 2 cm or more thick in which humilluvic materials constitute one-half or more of the volume. Luvihemists, p. 483 

BDD. Other Hemists that have a cryic temperature regime. Cryohemists, p. 480 

BDE. Other Hemists. Haplohemists, p. 481

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