Navigation

ชมรมดินปุ๋ยบนเว็บ

IGB.Calciudolls

Key to Great Groups 

IGB. Other Udolls that:

1. Have a calcic or petrocalcic horizon that has its upper boundary within 100 cm of the mineral soil surface; and

2. Do not have an argillic horizon above the calcic or petrocalcic horizon; and

3. In all parts above the calcic or petrocalcic horizon, after the materials between the soil surface and a depth of 18 cm have been mixed, either are calcareous or have a texture of loamy fine sand or coarser. Calciudolls, p. 592 

IGB. These are the Udolls with a calcic or petrocalcic horizon that has its upper boundary within 100 cm of the soil surface. Calciudolls do not have an argillic horizon above the calcic or petrocalcic horizon. They are calcareous in all subhorizons overlying the calcic horizon after the upper 18 cm has been mixed, unless the texture is coarser than loamy very fine sand or very fine sand. These soils are of small extent on the northern Great Plains of the United States. They are important in Argentina

Definition 

Calciudolls are the Udolls that:

1. Have a calcic or petrocalcic horizon that has its upper boundary within 100 cm of the soil surface;

2. Are calcareous in all parts of all horizons above the calcic horizon after the upper 18 cm has been mixed, unless the texture is coarser than loamy very fine sand or very fine sand;

3. Do not have an argillic horizon above the calcic or petrocalcic horizon; and

4. Do not have a natric horizon. 

Key to Subgroups 

IGBA. Calciudolls that have a lithic contact within 50 cm of the mineral soil surface. Lithic Calciudolls 

IGBB. Other Calciudolls that have one or both of the following:

1. Cracks within 125 cm of the mineral soil surface that are 5 mm or more wide through a thickness of 30 cm or more for some time in normal years, and slickensides or wedge-shaped aggregates in a layer 15 cm or more thick that has its upper boundary within 125 cm of the mineral soil surface; or

2. A linear extensibility of 6.0 cm or more between the mineral soil surface and either a depth of 100 cm or a densic, lithic, or paralithic contact, whichever is shallower. Vertic Calciudolls 

IGBC. Other Calciudolls that have, in one or more horizons within 100 cm of the mineral soil surface, redox depletions with chroma of 2 or less and also aquic conditions for some time in normal years (or artificial drainage). Aquic Calciudolls 

IGBD. Other Calciudolls that have a slope of less than 25 percent; and either:

1. An organic-carbon content of 0.3 percent or more at a depth of 125 cm below the mineral soil surface; or

2. An irregular decrease in organic-carbon content from a depth of 25 cm to a depth of 125 cm or to a lithic or paralithic contact if shallower. Fluventic Calciudolls 

IGBE. Other Calciudolls. Typic Calciudolls 

Definition of Typic Calciudolls 

Typic Calciudolls are the Udolls that:

1. Do not have a lithic contact within 50 cm of the mineral soil surface; and

2. Do not have either:

                a. Cracks within 125 cm of the mineral soil surface that are 5 mm or more wide through a thickness of 30 cm or more for some time in normal years, and slickensides or wedge-shaped aggregates in a layer 15 cm or more thick that has its upper boundary within 125 cm of the mineral soil surface; or

                b. A linear extensibility of 6.0 cm or more between the mineral soil surface and either a depth of 100 cm or a densic, lithic, or paralithic contact, whichever is shallower; and

3. Do not have, in any horizon within 100 cm of the mineral soil surface, redox depletions with chroma of 2 or less and also aquic conditions; and

4. Do not have a slope of less than 25 percent and either of the following:

                a. An organic-carbon content of 0.3 percent or more at a depth of 125 cm below the mineral soil surface; or

                b. An irregular decrease in organic-carbon content from a depth of 25 cm to a depth of 125 cm or to a lithic or paralithic contact if shallower.


pages by sootin claimon : sootinc@gmail.com