Ключи к почвенной таксономии 2014

or more and no densic, lithic, or paralithic contact within that depth; or

b.  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.

Udifluventic Haplustepts

KDEO.  Other Haplustepts that have all of the following: 1.  A slope of less than 25 percent; and

2.  Atotal thickness of less than 50 cm of humantransported material in the surface horizons; and

3.  One or both of the following:

a.  At a depth of 125 cm below the mineral soil surface, an organic-carbon content (Holocene age) of 0.2 percent or more and no densic, lithic, or paralithic contact within that depth; or

b.  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 Haplustepts

KDEP.  Other Haplustepts that have a gypsic horizon within

100 cm of the mineral soil surface.

Gypsic Haplustepts

KDEQ.  Other Haplustepts that have both:

1.  A calcic horizon within 100 cm of the mineral soil surface; and

2.  When neither irrigated nor fallowed to store moisture, one of the following:

a.  A frigid soil temperature regime and a moisture control section that in normal years is dry in all parts for four-tenths or more of the cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 5 oC; or

b.  A mesic or thermic soil temperature regime and a moisture control section that in normal years is dry in some part for six-tenths or more of the cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 5 oC; or

c.  A hyperthermic, isomesic, or warmer iso soil temperature regime and a moisture control section that in normal years:

(1)  Is moist in some or all parts for fewer than 90

consecutive days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 8 oC; and

(2)  Is dry in some part for six-tenths or more of the cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 5 oC.

Haplocalcidic Haplustepts

KDER.  Other Haplustepts that have both:

1.  A calcic horizon within 100 cm of the mineral soil surface; and

2.  When neither irrigated nor fallowed to store moisture, one of the following:

fallowed to store moisture, have one of the following:

1.  A frigid soil temperature regime and a moisture control section that in normal years is dry in all parts for four-tenths or more of the cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 5 oC; or

2.  A mesic or thermic soil temperature regime and a moisture control section that in normal years is dry in some part for six-tenths or more of the cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 5 oC; or

3.  A hyperthermic, isomesic, or warmer iso soil temperature regime and a moisture control section that in normal years:

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either an Ap horizon or a depth of 25 cm from the mineral soil surface, whichever is deeper, and either a depth of 75 cm below the mineral soil surface or a densic, lithic, or paralithic contact, whichever is shallower.

Dystric Haplustepts

KDEV.  Other Haplustepts that, when neither irrigated nor fallowed to store moisture, have one of the following:

1.  A frigid soil temperature regime and a moisture control section that in normal years is dry in some or all parts for fewer than 105 cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 5 oC; or

2.  A mesic or thermic soil temperature regime and a moisture control section that in normal years is dry in some part for less than four-tenths of the cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 5 oC; or

3.  A hyperthermic, isomesic, or warmer iso soil temperature regime and a moisture control section that in normal years is dry in some or all parts for fewer than 120 cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 8 oC.

Udic Haplustepts

KDEW.  Other Haplustepts.

Typic Haplustepts

Humustepts

Key to Subgroups

KDCA.  Humustepts that have a lithic contact within 50 cm of the mineral soil surface.

Lithic Humustepts

KDCB.  Other Humustepts 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 with both a bulk density of 1.0 g/cm3 or less, measured at 33 kPa water retention,

and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0.

Andic Humustepts

KDCC.  Other Humustepts that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the mineral 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; and

a.  In the 0.02 to 2.0 mm fraction, 5 percent or more volcanic glass; and

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

Vitrandic Humustepts

KDCD.  Other Humustepts that in normal years are saturated with water in one or more layers within 100 cm of the mineral soil surface for either or both:

1.  20 or more consecutive days; or

2.  30 or more cumulative days.

Oxyaquic Humustepts

KDCE.  Other Humustepts that have, in 50 percent or more of the soil volume between a depth of 25 cm from the mineral soil surface and either a depth of 100 cm or a densic, lithic, or paralithic contact if shallower:

1.  A CEC (by 1N NH4OAc pH 7) of less than 24 cmol(+) per kg clay; or

2.  Both a ratio of measured clay in the fine-earth fraction to percent water retained at 1500 kPa tension of 0.6 or more and the following: the CEC (by 1N NH4OAc pH 7) divided by the product of three times [percent water retained at 1500 kPa tension minus percent organic carbon (but no more than 1.00)] is less than 24.

Oxic Humustepts

KDCF.  Other Humustepts that, when neither irrigated nor fallowed to store moisture, have one of the following:

1.  A frigid soil temperature regime and a moisture control section that in normal years is dry in all parts for four-tenths or more of the cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 5 oC; or

2.  A mesic or thermic soil temperature regime and a moisture control section that in normal years is dry in some

part for six-tenths or more of the cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 5 oC; or

3.  A hyperthermic, isomesic, or warmer iso soil temperature regime and a moisture control section that in normal years:

a.  Is moist in some or all parts for fewer than 90 consecutive days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 8 oC; and

b.  Is dry in some part for six-tenths or more of the cumulative days per year when the soil temperature at a depth of 50 cm below the soil surface is higher than 5 oC.

Aridic Humustepts

KDCG.  Other Humustepts.

Typic Humustepts

Xerepts

Key to Great Groups

KEA.  Xerepts that have a duripan within 100 cm of the mineral soil surface.

Durixerepts, p. 204

KEB.  Other Xerepts that have a fragipan within 100 cm of the mineral soil surface.

Fragixerepts, p. 206

KEC.  Other Xerepts that have an umbric or mollic epipedon.

Humixerepts, p. 208

KED.  Other Xerepts that have both:

1.  A calcic horizon within 100 cm of the mineral soil surface or a petrocalcic horizon within 150 cm of the mineral soil surface; and

2.  Free carbonates in all parts above the calcic or petrocalcic horizon, after the soil between the mineral soil surface and a depth of 18 cm has been mixed.

Calcixerepts, p. 203

KEE.  Other Xerepts that have both of the following:

1.  No free carbonates within 200 cm of the mineral soil surface; and

2.  A base saturation (by NH4OAc) of less than 60 percent in all horizons at a depth between 25 and 75 cm from the mineral soil surface.

Dystroxerepts, p. 204

KEF.  Other Xerepts.

Haploxerepts, p. 206

Calcixerepts

Key to Subgroups

KEDA.  Calcixerepts that have a lithic contact within 50 cm of the mineral soil surface.

Lithic Calcixerepts

KEDB.  Other Calcixerepts 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 wedgeshaped 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 Calcixerepts

KEDC.  Other Calcixerepts that have a petrocalcic horizon within 100 cm of the mineral soil surface.

Petrocalcic Calcixerepts

KEDD.  Other Calcixerepts that have an exchangeable sodium percentage of 15 or more (or a sodium adsorption ratio [SAR] of 13 or more) in one or more subhorizons within 100 cm of the mineral soil surface.

Sodic Calcixerepts

KEDE.  Other Calcixerepts that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the mineral 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; and

within 75 cm of the mineral soil surface, redox depletions with

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chroma of 2 or less and also aquic conditions for some time in normal years (or artificial drainage).

Aquic Calcixerepts

KEDG.  Other Calcixerepts.

Typic Calcixerepts

Durixerepts

Key to Subgroups

KEAA.  Durixerepts that have both:

1.  In one or more horizons above the duripan and within 30 cm of the mineral soil surface, distinct or prominent redox concentrations and also aquic conditions for some time in normal years (or artificial drainage); and

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

a.  Afine-earth fraction with both a bulk density of 1.0 g/cm3 or less, measured at 33 kPa water retention, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0; or

b.  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

c.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter; and

(1)  In the 0.02 to 2.0 mm fraction, 5 percent or more volcanic glass; and

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

Aquandic Durixerepts

KEAB.  Other Durixerepts that have, throughout one or more horizons with a total thickness of 18 cm or more, above the duripan and within 75 cm of the mineral soil surface, a fine-earth fraction with both a bulk density of 1.0 g/cm3 or less, measured at 33 kPa water retention, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0.

Andic Durixerepts

KEAC.  Other Durixerepts that have, throughout one or more horizons with a total thickness of 18 cm or more, above the duripan and within 75 cm of the mineral 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; and

above the duripan and within 30 cm of the mineral soil surface, distinct or prominent redox concentrations and also aquic conditions for some time in normal years (or artificial drainage).

Dystroxerepts

Key to Subgroups

KEEA.  Dystroxerepts that have both:

1.  A lithic contact within 50 cm of the mineral soil surface; and

2.  A color value, moist, of 3 or less and a color value, dry, of 5 or less (crushed and smoothed sample) either throughout the upper 18 cm of the mineral soil (unmixed) or between the mineral soil surface and a depth of 18 cm after mixing.

Humic Lithic Dystroxerepts

KEEB.  Other Dystroxerepts that have a lithic contact within

50 cm of the mineral soil surface.

Lithic Dystroxerepts

KEEC.  Other Dystroxerepts that have both:

1.  In one or more horizons within 75 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); and

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

a.  Afine-earth fraction with both a bulk density of 1.0 g/cm3 or less, measured at 33 kPa water retention, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0; or

b.  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

c.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter; and

(1)  In the 0.02 to 2.0 mm fraction, 5 percent or more volcanic glass; and

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

Aquandic Dystroxerepts

KEED.  Other Dystroxerepts 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 with both a bulk density of 1.0 g/cm3 or less, measured at 33 kPa water retention, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0.

Andic Dystroxerepts

KEEE.  Other Dystroxerepts that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the mineral 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; and

oxalate) times 60] plus the volcanic glass (percent) is equal to 30 or more.

Vitrandic Dystroxerepts

KEEF.  Other Dystroxerepts that have both: 1.  Fragic soil properties either:

a.  In 30 percent or more of the volume of a layer 15 cm or more thick that has its upper boundary within 100 cm of the mineral soil surface; or

b.  In 60 percent or more of the volume of a layer 15 cm or more thick; and

2.  In one or more horizons within 75 cm of the mineral soil surface, redox depletions with chroma of 2 or less and also aquic conditions in normal years (or artificial drainage).

Fragiaquic Dystroxerepts

KEEG.  Other Dystroxerepts that have all of the following: 1.  A slope of less than 25 percent; and

2.  Atotal thickness of less than 50 cm of humantransported material in the surface horizons; and

3.  In one or more horizons within 75 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); and

4.  One or both of the following:

a.  At a depth of 125 cm below the mineral soil surface, an organic-carbon content (Holocene age) of 0.2 percent or more and no densic, lithic, or paralithic contact within that depth; or

b.  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.

with water in one or more layers within 100 cm of the mineral soil surface for either or both:

1.  20 or more consecutive days; or

2.  30 or more cumulative days.

Oxyaquic Dystroxerepts

KEEJ.  Other Dystroxerepts that have fragic soil properties either:

1.  In 30 percent or more of the volume of a layer 15 cm or more thick that has its upper boundary within 100 cm of the mineral soil surface; or

2.  In 60 percent or more of the volume of a layer 15 cm or more thick.

Fragic Dystroxerepts

KEEK.  Other Dystroxerepts that have all of the following: 1.  A slope of less than 25 percent; and

2.  Atotal thickness of less than 50 cm of humantransported material in the surface horizons; and

3.  A color value, moist, of 3 or less and a color value, dry, of 5 or less (crushed and smoothed sample) either throughout the upper 18 cm of the mineral soil (unmixed) or between the mineral soil surface and a depth of 18 cm after mixing; and

4.  One or both of the following:

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a.  At a depth of 125 cm below the mineral soil surface, an organic-carbon content (Holocene age) of 0.2 percent or more and no densic, lithic, or paralithic contact within that depth; or

b.  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 Humic Dystroxerepts

KEEL.  Other Dystroxerepts that have all of the following: 1.  A slope of less than 25 percent; and

2.  Atotal thickness of less than 50 cm of humantransported material in the surface horizons; and

3.  One or both of the following:

a.  At a depth of 125 cm below the mineral soil surface, an organic-carbon content (Holocene age) of 0.2 percent or more and no densic, lithic, or paralithic contact within that depth; or

b.  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 Dystroxerepts

KEEM.  Other Dystroxerepts that have a color value, moist, of 3 or less and a color value, dry, of 5 or less (crushed and smoothed sample) either throughout the upper 18 cm of the mineral soil (unmixed) or between the mineral soil surface and a depth of 18 cm after mixing.

Humic Dystroxerepts

KEEN.  Other Dystroxerepts.

Typic Dystroxerepts

Fragixerepts

Key to Subgroups

KEBA.  Fragixerepts 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 with both a bulk density of 1.0 g/cm3 or less, measured at 33 kPa water retention, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0.

Andic Fragixerepts

KEBB.  Other Fragixerepts that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the mineral 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; and

within 30 cm of the mineral soil surface, distinct or prominent redox concentrations and also aquic conditions for some time in normal years (or artificial drainage).

Aquic Fragixerepts

KEBD.  Other Fragixerepts that have one or both of the following:

1.  An umbric or mollic epipedon; or

2.  A color value, moist, of 3 or less and a color value, dry, of 5 or less (crushed and smoothed sample) either throughout the upper 18 cm of the mineral soil (unmixed) or between the mineral soil surface and a depth of 18 cm after mixing.

Humic Fragixerepts

KEBE.  Other Fragixerepts.

Typic Fragixerepts

Haploxerepts

Key to Subgroups

KEFA.  Haploxerepts that have both:

1.  A lithic contact within 50 cm of the mineral soil surface; and

2.  A color value, moist, of 3 or less and a color value, dry, of 5 or less (crushed and smoothed sample) either throughout the upper 18 cm of the mineral soil (unmixed) or between the mineral soil surface and a depth of 18 cm after mixing.

Humic Lithic Haploxerepts

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 wedgeshaped 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 Haploxerepts

KEFD.  Other Haploxerepts that have both:

1.  In one or more horizons within 75 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); and

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

a.  Afine-earth fraction with both a bulk density of 1.0 g/cm3 or less, measured at 33 kPa water retention, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0; or

b.  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

c.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter; and

(1)  In the 0.02 to 2.0 mm fraction, 5 percent or more volcanic glass; and

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

Aquandic Haploxerepts

KEFE.  Other Haploxerepts that have both:

1.  In 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 with both a bulk density of 1.0 g/cm3 or less, measured at 33 kPa water retention, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0; and

2.  Saturation with water within 100 cm of the mineral soil surface in normal years for either or both:

horizons with a total thickness of 18 cm or more within 75 cm of the mineral soil surface, a fine-earth fraction with both a bulk

density of 1.0 g/cm3 or less, measured at 33 kPa water retention, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0.

Andic Haploxerepts

KEFG.  Other Haploxerepts that have both:

1.  Saturation with water within 100 cm of the mineral soil surface in normal years for either or both:

2.  Throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the mineral soil surface, one or more 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; and

(1)  In the 0.02 to 2.0 mm fraction, 5 percent or more volcanic glass; and

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

Oxyaquic Vitrandic Haploxerepts

KEFH.  Other Haploxerepts that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the mineral 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; and

within 75 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 Haploxerepts

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1.  In 30 percent or more of the volume of a layer 15 cm or more thick that has its upper boundary within 100 cm of the mineral soil surface; or

2.  In 60 percent or more of the volume of a layer 15 cm or more thick.

Fragic Haploxerepts

KEFM.  Other Haploxerepts that have all of the following: 1.  A slope of less than 25 percent; and

2.  Atotal thickness of less than 50 cm of humantransported material in the surface horizons; and

3.  One or both of the following:

a.  At a depth of 125 cm below the mineral soil surface, an organic-carbon content (Holocene age) of 0.2 percent or more and no densic, lithic, or paralithic contact within that depth; or

b.  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 Haploxerepts

KEFN.  Other Haploxerepts that have a calcic horizon or identifiable secondary carbonates within one of the following particle-size class and depth combinations:

1.  Asandy or sandy-skeletal particle-size class and within

150 cm of the mineral soil surface; or

2.  Aclayey, clayey-skeletal, fine, or very-fine particle-size class and within 90 cm of the mineral soil surface; or

3.  Any other particle-size class and within 110 cm of the mineral soil surface.

Calcic Haploxerepts

KEFO.  Other Haploxerepts that have a color value, moist, of 3 or less and a color value, dry, of 5 or less (crushed and smoothed sample) either throughout the upper 18 cm of the mineral soil (unmixed) or between the mineral soil surface and a depth of 18 cm after mixing.

Humic Haploxerepts

KEFP.  Other Haploxerepts.

Typic Haploxerepts

Humixerepts

Key to Subgroups

KECA.  Humixerepts that have a lithic contact within 50 cm of the mineral soil surface.

Lithic Humixerepts

KECB.  Other Humixerepts that have both:

1.  In one or more horizons within 75 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); and

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

a.  Afine-earth fraction with both a bulk density of 1.0 g/cm3 or less, measured at 33 kPa water retention, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0; or

b.  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

c.  Afine-earth fraction containing 30 percent or more particles 0.02 to 2.0 mm in diameter; and

(1)  In the 0.02 to 2.0 mm fraction, 5 percent or more volcanic glass; and

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

Aquandic Humixerepts

KECC.  Other Humixerepts 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 with both a bulk density of 1.0 g/cm3 or less, measured at 33 kPa water retention, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0.

Andic Humixerepts

KECD.  Other Humixerepts that have, throughout one or more horizons with a total thickness of 18 cm or more within 75 cm of the mineral 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; and

a.  In the 0.02 to 2.0 mm fraction, 5 percent or more volcanic glass; and

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

Vitrandic Humixerepts

KECE.  Other Humixerepts that have, in one or more horizons within 75 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 Humixerepts

KECF.  Other Humixerepts that in normal years are saturated with water in one or more layers within 100 cm of the mineral soil surface for either or both:

1.  20 or more consecutive days; or

2.  30 or more cumulative days.

Oxyaquic Humixerepts

KECG.  Other Humixerepts that have all of the following: 1.  A slope of less than 25 percent; and

2.  Atotal thickness of less than 50 cm of humantransported material in the surface horizons; and

3.  An umbric or mollic epipedon that is 50 cm or more thick; and

4.  One or both of the following:

a.  At a depth of 125 cm below the mineral soil surface, an organic-carbon content (Holocene age) of 0.2 percent or more and no densic, lithic, or paralithic contact within that depth; or

b.  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.

Cumulic Humixerepts

KECH.  Other Humixerepts that have all of the following: 1.  A slope of less than 25 percent; and

2.  Atotal thickness of less than 50 cm of humantransported material in the surface horizons; and

3.  One or both of the following:

a.  At a depth of 125 cm below the mineral soil surface, an organic-carbon content (Holocene age) of 0.2 percent or more and no densic, lithic, or paralithic contact within that depth; or

b.  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.

and do not, in any part of the umbric or mollic epipedon, meet the requirements for a cambic horizon, except for the color requirements.

Entic Humixerepts

KECK.  Other Humixerepts.

Typic Humixerepts

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