Ключи к почвенной таксономии 2014

that contain 20 percent or more (by volume) nodules or concretions; and

2.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on ustic.

Petronodic Ustic Haplocambids

GGCK.  Other Haplocambids that have one or more horizons, within 100 cm of the soil surface and with a combined thickness of 15 cm or more, that contain 20 percent or more (by volume) nodules or concretions.

Petronodic Haplocambids

GGCL.  Other Haplocambids that have both:

1.  A horizon at least 25 cm thick within 100 cm of the soil surface that has an exchangeable sodium percentage of 15 or more (or an SAR of 13 or more) during at least 1 month in normal years; and

2.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric.

Sodic Xeric Haplocambids

GGCM.  Other Haplocambids that have both:

1.  A horizon at least 25 cm thick within 100 cm of the soil surface that has an exchangeable sodium percentage of 15 or more (or an SAR of 13 or more) during at least 1 month in normal years; and

2.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on ustic.

Sodic Ustic Haplocambids

GGCN.  Other Haplocambids that have, in a horizon at least

25 cm thick within 100 cm of the soil surface, an exchangeable sodium percentage of 15 or more (or an SAR of 13 or more) during at least 1 month in normal years.

Sodic Haplocambids

GGCO.  Other Haplocambids that have both:

1.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric; and

2.  Throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

a.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

b.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is volcanic glass, and [(Al plus 1/2 Fe, percent extracted by ammonium oxalate) times 60] plus the volcanic glass (percent) is 30 or more.

Vitrixerandic Haplocambids

GGCP.  Other Haplocambids that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

1.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

2.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is 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 Haplocambids

GGCQ.  Other Haplocambids that meet all of the following:

1.  Have a total thickness of less than 50 cm of humantransported material in the surface horizons; and

2.  In normal years, are dry in all parts of the moisture control section for less than three-fourths of the time

(cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on xeric; and

3.  Have an irregular decrease in organic-carbon content

(Holocene age) between a depth of 25 cm and either a depth of 125 cm below the mineral soil surface or a densic, lithic, or paralithic contact, whichever is shallower.

Xerofluventic Haplocambids

GGCR.  Other Haplocambids that meet all of the following:

1.  Have a total thickness of less than 50 cm of humantransported material in the surface horizons; and

2.  In normal years, are dry in all parts of the moisture control section for less than three-fourths of the time

(cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on ustic; and

3.  Have an irregular decrease in organic-carbon content

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(Holocene age) between a depth of 25 cm and either a depth of 125 cm below the mineral soil surface or a densic, lithic, or paralithic contact, whichever is shallower.

Ustifluventic Haplocambids

GGCS.  Other Haplocambids that meet both of the following:

1.  Have a total thickness of less than 50 cm of humantransported material in the surface horizons; and

2.  Have an irregular decrease in organic-carbon content

(Holocene age) between a depth of 25 cm and either a depth of 125 cm below the mineral soil surface or a densic, lithic, or paralithic contact, whichever is shallower.

Fluventic Haplocambids

in all parts of the moisture control section for less than threefourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on xeric.

Xeric Haplocambids

GGCV.  Other Haplocambids that, in normal years, are dry in all parts of the moisture control section for less than threefourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on ustic.

Ustic Haplocambids

GGCW.  Other Haplocambids.

Typic Haplocambids

Petrocambids

Key to Subgroups

GGBA.  Petrocambids that have, in a horizon at least 25 cm thick within 100 cm of the soil surface, an exchangeable sodium percentage of 15 or more (or an SAR of 13 or more) during at least 1 month in normal years.

Sodic Petrocambids

GGBB.  Other Petrocambids that have both:

1.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric; and

2.  Throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

1.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

2.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is 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 Petrocambids

GGBD.  Other Petrocambids that, in normal years, are dry in all parts of the moisture control section for less than threefourths of the time (cumulative) when the soil temperature at a

depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on xeric.

Xeric Petrocambids

GGBE.  Other Petrocambids that, in normal years, are dry in all parts of the moisture control section for less than threefourths of the time (cumulative) when the soil temperature at a

depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on ustic.

Ustic Petrocambids

GGBF.  Other Petrocambids.

Typic Petrocambids

Cryids

Key to Great Groups

GAA.  Cryids that have a salic horizon within 100 cm of the soil surface.

Salicryids, p. 126

GAB.  Other Cryids that have a duripan, petrocalcic horizon, or petrogypsic horizon within 100 cm of the soil surface.

Petrocryids, p. 125

Argicryids

Key to Subgroups

GADA.  Argicryids that have a lithic contact within 50 cm of the soil surface.

Lithic Argicryids

GADB.  OtherArgicryids that have one or both of the following:

1.  Cracks within 125 cm of the soil surface that are 5 mm or more wide throughout a thickness of 30 cm or more for some time in normal years and slickensides or wedge-

shaped peds in a layer 15 cm or more thick that has its upper boundary within 125 cm of the mineral soil surface; or

2.  Alinear 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 Argicryids

1.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric; and

2.  Throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

a.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

b.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent

or more is volcanic glass, and [(Al plus 1/2 Fe, percent extracted by ammonium oxalate) times 60] plus the volcanic glass (percent) is 30 or more.

Vitrixerandic Argicryids

GADE.  OtherArgicryids that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

1.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

2.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is 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 Argicryids

GADF.  OtherArgicryids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on xeric.

Xeric Argicryids

GADG.  OtherArgicryids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on ustic.

Ustic Argicryids

GADH.  OtherArgicryids.

Typic Argicryids

Calcicryids

Key to Subgroups

GAEA.  Calcicryids that have a lithic contact within 50 cm of the soil surface.

Lithic Calcicryids

GAEB.  Other Calcicryids that have both:

1.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric; and

2.  Throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

a.  More than 35 percent (by volume) particles 2.0 mm

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or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

b.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is volcanic glass, and [(Al plus 1/2 Fe, percent extracted by ammonium oxalate) times 60] plus the volcanic glass (percent) is 30 or more.

Vitrixerandic Calcicryids

GAEC.  Other Calcicryids that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

1.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

2.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is 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 Calcicryids

GAED.  Other Calcicryids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on xeric.

Xeric Calcicryids

GAEE.  Other Calcicryids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on ustic.

Ustic Calcicryids

GAEF.  Other Calcicryids.

Typic Calcicryids

Gypsicryids

Key to Subgroups

GACA.  Gypsicryids that have a calcic horizon.

Calcic Gypsicryids

GACB.  Other Gypsicryids that have both:

1.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric; and

2.  Throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

1.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

2.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is 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 Gypsicryids

GACD.  Other Gypsicryids.

Typic Gypsicryids

Haplocryids

Key to Subgroups

GAFA.  Haplocryids that have a lithic contact within 50 cm of the soil surface.

Lithic Haplocryids

GAFB.  Other Haplocryids that have one or both of the following:

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

2.  Alinear 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 Haplocryids

GAFC.  Other Haplocryids that have both:

1.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric; and

2.  Throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

1.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

2.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is 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 Haplocryids

GAFE.  Other Haplocryids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on xeric.

Xeric Haplocryids

GAFF.  Other Haplocryids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on ustic.

Ustic Haplocryids

GAFG.  Other Haplocryids.

Typic Haplocryids

Petrocryids

Key to Subgroups

GABA.  Petrocryids that have both:

1.  A duripan that is strongly cemented or less cemented in all subhorizons within 100 cm of the soil surface;

and

2.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric.

Xereptic Petrocryids

GABB.  Other Petrocryids that have both:

1.  A duripan within 100 cm of the soil surface; and

2.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric.

parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on xeric.

Xeric Petrocryids

GABF.  Other Petrocryids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on ustic.

Ustic Petrocryids

GABG.  Other Petrocryids.

Typic Petrocryids

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Salicryids

Key to Subgroups

GAAA.  Salicryids that are saturated with water in one or more layers within 100 cm of the soil surface for 1 month or more in normal years.

Aquic Salicryids

GAAB.  Other Salicryids.

Typic Salicryids

Durids

Key to Great Groups

Argidurids

Key to Subgroups

GCBA.  Argidurids that have one or both of the following:

1.  Cracks between the soil surface and the top of the duripan 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 peds in a layer 15 cm or more thick that is above the duripan; or

2.  Alinear extensibility of 6.0 cm or more between the soil surface and the top of the duripan.

Vertic Argidurids

GCBB.  OtherArgidurids that are either:

1.  Irrigated and have aquic conditions for some time in normal years in one or more layers within 100 cm of the soil surface; or

2.  Saturated with water in one or more layers within 100 cm of the soil surface for 1 month or more in normal years.

Aquic Argidurids

GCBC.  OtherArgidurids that have both:

1.  An argillic horizon that has 35 percent or more noncarbonate clay throughout one or more subhorizons and one or more of the following:

a.  A clay increase of 15 percent or more (absolute, in the fine-earth fraction) within a vertical distance of 2.5 cm either within the argillic horizon or at its upper boundary; or

b.  If there is an Ap horizon directly above the argillic horizon, a clay increase of 10 percent or more (absolute, in the fine-earth fraction) at the upper boundary of the argillic horizon; or

c.  An abrupt textural change between the eluvial horizon and the upper boundary of the argillic horizon; and

2.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric.

Abruptic Xeric Argidurids

GCBD.  OtherArgidurids that have an argillic horizon that has

35 percent or more noncarbonate clay throughout one or more subhorizons and one or more of the following:

1.  A clay increase of 15 percent or more (absolute, in the fine-earth fraction) within a vertical distance of 2.5 cm either within the argillic horizon or at its upper boundary; or

2.  If there is an Ap horizon directly above the argillic horizon, a clay increase of 10 percent or more (absolute, in the fine-earth fraction) at the upper boundary of the argillic horizon; or

3.  An abrupt textural change between the eluvial horizon and the upper boundary of the argillic horizon.

Abruptic Argidurids

GCBE.  OtherArgidurids that have both:

1.  A duripan that is strongly cemented or less cemented in all subhorizons; and

2.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric.

1.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

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GCCF.  Other Haplodurids that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

1.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

2.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is 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 Haplodurids

GCCG.  Other Haplodurids that have a mean annual soil temperature lower than 22 oC, a difference of 5 oC or more between mean summer and mean winter soil temperatures at a depth of 50 cm, and a soil moisture regime that borders on xeric.

Xeric Haplodurids

GCCH.  Other Haplodurids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on ustic.

Ustic Haplodurids

GCCI.  Other Haplodurids.

Typic Haplodurids

Natridurids

Key to Subgroups

GCAA.  Natridurids that have one or both of the following:

1.  Cracks between the soil surface and the top of the duripan 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 peds in a layer 15 cm or more thick that is above the duripan; or

2.  Alinear extensibility of 6.0 cm or more between the soil surface and the top of the duripan.

Vertic Natridurids

GCAB.  Other Natridurids that meet both of the following:

1.  Have a duripan that is strongly cemented or less cemented in all subhorizons; and

2.  Are either:

a.  Irrigated and have aquic conditions for some time in normal years in one or more layers within 100 cm of the soil surface; or

b.  Saturated with water in one or more layers within 100 cm of the soil surface for 1 month or more in normal years.

Aquic Natrargidic Natridurids

GCAC.  Other Natridurids that are either:

1.  Irrigated and have aquic conditions for some time in normal years in one or more layers within 100 cm of the soil surface; or

2.  Saturated with water in one or more layers within 100 cm of the soil surface for 1 month or more in normal years.

Aquic Natridurids

GCAD.  Other Natridurids that have both:

1.  A duripan that is strongly cemented or less cemented in all subhorizons; and

2.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric.

Natrixeralfic Natridurids

GCAE.  Other Natridurids that have a duripan that is strongly cemented or less cemented in all subhorizons.

Natrargidic Natridurids

GCAF.  Other Natridurids that have both:

1.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric; and

2.  Throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

1.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

2.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is 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 Natridurids

GCAH.  Other Natridurids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on xeric.

Argigypsids

Key to Subgroups

GDCA.  Argigypsids that have a lithic contact within 50 cm of the soil surface.

Lithic Argigypsids

GDCB.  OtherArgigypsids that have one or both of the following:

1.  Cracks within 125 cm of the 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 peds in a layer 15 cm or more thick that has its upper boundary within 125 cm of the soil surface; or

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

Vertic Argigypsids

within 100 cm of the soil surface and with a combined thickness of 15 cm or more, that contain 20 percent or more (by volume) durinodes, nodules, or concretions.

Petronodic Argigypsids

GDCE.  OtherArgigypsids that have both:

1.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric; and

2.  Throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

1.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

2.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is volcanic glass, and [(Al plus 1/2 Fe, percent extracted by ammonium oxalate) times 60] plus the volcanic glass

(percent) is 30 percent or more.

Vitrandic Argigypsids

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GDCG.  OtherArgigypsids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on xeric.

Xeric Argigypsids

GDCH.  OtherArgigypsids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on ustic.

Ustic Argigypsids

GDCI.  OtherArgigypsids.

Typic Argigypsids

Calcigypsids

Key to Subgroups

GDDA.  Calcigypsids that have a lithic contact within 50 cm of the soil surface.

Lithic Calcigypsids

GDDB.  Other Calcigypsids that have one or more horizons, within 100 cm of the soil surface and with a combined thickness of 15 cm or more, that contain 20 percent or more (by volume) durinodes, nodules, or concretions.

Petronodic Calcigypsids

GDDC.  Other Calcigypsids that have both:

1.  A moisture control section that, in normal years, is dry in all parts for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the

soil surface is 5 oC or higher and a soil moisture regime that borders on xeric; and

2.  Throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

a.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

b.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is volcanic glass, and [(Al plus 1/2 Fe, percent extracted by ammonium oxalate) times 60] plus the volcanic glass (percent) is 30 or more.

Vitrixerandic Calcigypsids

GDDD.  Other Calcigypsids that have, throughout one or more

horizons with a total thickness of 18 cm or more within 75 cm of the soil surface, one or both of the following:

1.  More than 35 percent (by volume) particles 2.0 mm or larger in diameter, of which more than 66 percent is cinders, pumice, and pumicelike fragments; or

2.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter, of which 5 percent or more is 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 Calcigypsids

GDDE.  Other Calcigypsids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on xeric.

Xeric Calcigypsids

GDDF.  Other Calcigypsids that, in normal years, are dry in all parts of the moisture control section for less than three-fourths of the time (cumulative) when the soil temperature at a depth of 50 cm below the soil surface is 5 oC or higher and have a soil moisture regime that borders on ustic.

Ustic Calcigypsids

GDDG.  Other Calcigypsids.

Typic Calcigypsids

Haplogypsids

Key to Subgroups

GDEA.  Haplogypsids that have a lithic contact within 50 cm of the soil surface.

Lithic Haplogypsids

GDEB.  Other Haplogypsids that have a gypsic horizon within

18 cm of the soil surface.

Leptic Haplogypsids

GDEC.  Other Haplogypsids that have, in a horizon at least

25 cm thick within 100 cm of the mineral soil surface, an exchangeable sodium percentage of 15 or more (or an SAR of 13 or more) during at least 1 month in normal years.

Sodic Haplogypsids

GDED.  Other Haplogypsids that have one or more horizons, within 100 cm of the soil surface and with a combined thickness of 15 cm or more, that contain 20 percent or more (by volume) durinodes, nodules, or concretions.

Petronodic Haplogypsids