LCB.Torripsamments

Key to Great Groups 

LCB. Other Psamments that have an aridic (or torric) moisture regime. Torripsamments, p. 436 

LCB. These are the cool to hot Psamments of arid climates. They have an aridic (or torric) moisture regime and a temperature regime warmer than cryic. Many of these soils are on stable surfaces, some are on dunes, some are stabilized, and some are moving. Torripsamments consist of quartz, mixed sands, volcanic glass, or even gypsum and may have any color. Generally, they are neutral or calcareous and are nearly level to steep. The vegetation consists mostly of xerophytic shrubs, grasses, and forbs. Many of these soils support more vegetation than other soils with an aridic moisture regime, presumably because they lose less water as runoff. Some of the soils on dunes support a few ephemeral plants or have a partial cover of xerophytic and ephemeral plants. The shifting dunes may be devoid of plants in normal years. Most of the deposits are of late-Pleistocene or younger age. These soils are used mainly for grazing. They are extensive in the Western United States. 

Definition 

Torripsamments are the Psamments that have an aridic (or torric) moisture regime and a soil temperature regime warmer than cryic. 

Key to Subgroups 

LCBA. Torripsamments that have a lithic contact within 50 cm of the soil surface. Lithic Torripsamments 

LCBB. Other Torripsamments that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the mineral soil surface, a fine-earth fraction containing 5 percent or more volcanic glass, and [(Al plus 1/2 Fe, percent extracted by ammonium oxalate) times 60] plus the volcanic glass (percent) is 30 or more. Vitrandic Torripsamments 

LCBC. Other Torripsamments that have a horizon within 100 cm of the soil surface that is 15 cm or more thick and that either has 20 percent or more (by volume) durinodes or is brittle and has a firm rupture-resistance class when moist. Haploduridic Torripsamments 

LCBD. Other Torripsamments that have both:

1. A moisture control section that, in normal years, is dry in all its parts for less than three-fourths of the cumulative days per year when the soil temperature at a depth of 50 cm from the soil surface is 5 oC or higher; and

2. An aridic (or torric) moisture regime that borders on ustic. Ustic Torripsamments 

LCBE. Other Torripsamments that have both:

1. A moisture control section that, in normal years, is dry in all its parts for less than three-fourths of the cumulative days per year when the soil temperature at a depth of 50 cm from the soil surface is 5 oC or higher; and

2. A thermic, mesic, or frigid soil temperature regime and an aridic (or torric) moisture regime that borders on xeric. Xeric Torripsamments 

LCBF. Other Torripsamments that have, in all horizons from a depth of 25 to 100 cm, more than 50 percent colors that have all of the following:

1. Hue of 2.5YR or redder; and

2. A color value, moist, of 3 or less; and

3. A dry value no more than 1 unit higher than the moist value. Rhodic Torripsamments 

LCBG. Other Torripsamments. Typic Torripsamments 

Definition of Typic Torripsamments 

Typic Torripsamments are the Torripsamments that:

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

2. Do not have a horizon within 100 cm of the surface that is more than 15 cm thick and that either has 20 percent or more durinodes or is brittle and has a firm rupture-resistance class when moist;

3. Are dry in all parts of the moisture control section for three-fourths or more of the time (cumulative) when the soil temperature at a depth of 50 cm is 5 oC or higher;

4. Do not have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the mineral soil surface, a fine-earth fraction containing 5 percent or more volcanic glass, and [(Al plus 1/2 Fe, percent extracted by ammonium oxalate) times 60] plus the volcanic glass (percent) is 30 or more; and

5. Do not have, in all horizons from a depth of 25 to 100 cm, more than 50 percent colors that have all of the following:

                1. Hue of 2.5YR or redder; and

                2. A color value, moist, of 3 or less; and

                3. A dry value no more than 1 unit higher than the moist value.

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