soil taxonomynew

8/10/2019 Soil Taxonomynew

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Using

SOILT XONOMY

to Identify Hydric Soils


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Soil Taxonomy is

A basic system of soil classification formaking and interpreting soil surveys.

Objective:To develop a hierarchical classificationthat reflects the relationships between

different soils, and between soils and thefactors responsible for their character.


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Soil Taxonomy

Procedure:

Soils are classified on the basis of:

Soil properties observed in the field (e.g.,soil horizons, texture, color, pH)and

Soil properties inferred from the

combined data of soil science and otherdisciplines (e.g., soil temperature andmoisture regimes inferred from soil science andmeteorology).


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Soil Taxonomy

Series

Family

Sub Group

Great Group

Sub OrderFirst sign of wetness

Order12 Orders

Entisol

Fluvent

Ustic

Fine-loamy, mixed, frigid

Korchea

Mollic


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Fine-loamy,

mixed

(calcareous),frigid,

Mollic

Ustifluvent

Korchea

Series

Not Hydric


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Soil Taxonomy

Nature of

Number Differentiating

Category of Taxa Characteristics

Order 12 Soil-forming processes

as indicated by

presence or

absence of majordiagnostic horizons


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Soil Orders

Alfisols

Andisols

AridisolsEntisols

Gelisols

Histosols

Inceptisols

Mollisols

OxisolsSpodosols

Ultisols

Vertisols


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Taxonomic Names

Soil Order

Alfisols

Andisols

Aridisols

Entisols

Gelisols

Histosols

Inceptisols

MollisolsOxisols

Spodosols

Ultisols

Vertisols

Names Ends in:

-Alf

-And

-Id

-Ent

-El

-Ist

-Ept

-Oll-Ox

-Od

-Ult

-Ert


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Entisol Suborders

Aquents

(L. Aqua, Water)

Wet Entisols

Fluvents

(L. Fluvius, River)

Floodplain Soils

Orthents

(Gr. Orthos, True)

The Common Ones

Psamments

(Gr. Psammons, Sand)

Sandy Soils


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Entisol Great Groups

Suborder

Aquents

(Wet Entisols)

Great Group

Cryaquents - cold

Fluvaquents - flood plainHydraquents - water

Psammaquents - sand

Epiaquents - perched


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Entisol Great Groups

SuborderFluvents

(Floodplain soils)

Great GroupCryofluvents

Torrifluvents - Torrid

(hot and dry)Tropofluvents

Udifluvents - Humid

(not dry in most years)

Ustifluvents - Semi-arid(between Udic-Aridic)

Xerofluvents - Semi-arid

(moist cold winter - dry

warm summer;Mediterranean climate)


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Soil Taxonomy

Suborder

Psamments

(Sandy Soils)

Great Group

Cryopsamments

Quartzipsamments -Quartz

Torripsamments

Udipsamments

UstipsammentsXeropsamments


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Soil Taxonomy -How to interpret the formative elements

Sub group - Great group, Suborder, Order

4 3 2 1

for example -

Vertic Udifluvent

4 - Vertic sub group - invert, shrink-swell, high clay

3 - Udi(c) great group - humid

2 - Fluv(ic) suborder - floodplain

1 - Ent(isol) order - little soil development


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Aquic Soil Moisture Regimes

Typic SubgroupAquic Suborder____ ___aq___

wettest

Aeric Subgroup

Aquic SuborderAeric ___aq___

better aerated

Aquic SubgroupAquic ______

driest

From Mausbach 1992


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Subgroups

4 3 2 1

Typic Fluvaquents

4 1 2

Typical Entisols with aquic moisture

3

regimes that occur on floodplains.

1. Order 3. Great Group

2. Suborder 4. Subgroup


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Subgroups

4 3 2 1

Mollic Fluvaquents

1 2

Entisols with aquic moisture regimes that

3

occur on floodplains, and that have thick,

4dark surface layers.




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Subgroups

4 3 2 1

Aeric Fluvaquents1 3 2

Entisols, occurring on floodplains, with an aquic

moisture regime that are not so wet. Better

4aerated in the upper part of the soil.




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Soil Taxonomy

Nature of

Number Differentiating

Category of Taxa Characteristics

Series 15,000+ A series may have virtually the

full range that is permitted in a

family in several properties, but

in one or more properties the

range is restricted, such as:- Kind and arrangement of

horizons

- Color

- Texture

- Structure


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Soil Taxonomy- Predicting

Problem Hydric Soils

Formative

Element

Soil

Order

Why a Problem

Alf Alfisols Gray / White (high value / low chroma)horizon below A, not always indicative of

wetness.

And Andisols Fe immobilized, redox. features are often

deeper than depth to water table. Some

Andisols have thick, dark colored surfacelayers.

Ent Entisols Recent depositional events exceed rate of

typical hydric morphology formation. Also

many sandy soils are Entisols.


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Problem Orders, cont.

Oll Mollisols Dark colored surface layers "mask" redox features.

Check colors below mollic, allow surface layers to

dry then look for redox (NTCHS Indicator F6).

Od Spodosols Sandy surface layers, no redox features evident inupper part. (Use organic layers, dark surface, and

stripped matrix indicators).

Ult Ultisols Some have gray / white (high value / low chroma)

horizon below A, not necessarily indicative of

wetness.Ert Vertisols High shrink-swell clays, surface hydrology. Many

Vertisols also have dark-colored surface layers.


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Problem Great Groups

Alb Albic horizon Gray / White (high value / low chroma)

horizon below A, not necessarily indicative

of wetness

Calci,

calc

Presence of a

calcic horizon

Gray / White (high value / low chroma)

horizon below A, not necessarily indicative

of wetness

Dur Presence of a

Duripan

(dense layer)

Subsoil may be brownish color.

Perched water table situation.

Epi Perched

water table

Subsoil may be brownish color.

Fluv Floodplain Surface hydrology, recent deposition


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Great Groups, cont.

Fragi Presence of a

Fragipan (dense layer)

Subsoil may be brownish

color, perched water table.

Gloss Presence of a Glossic

horizon

Multi-colored horizon below

A horizon.

Melan High organic content Dark colors may mask

redox features.

Psamm Sandy texture No, or low Fe content, also

low OM.

Sal Presence of a Salic

horizon

High pH, low OM; no, or few

redox features.


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Typic Haplosaprists


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Torry Series

Hydric


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Terric Haplosaprists


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Tawas

Series

Hydric


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Lithic Cryofolists


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Ricker

Series

Not Hydric


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Aquic Paleudalfs


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Katy

Series

Not Hydric


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Aquic Glossudalfs


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Withee

Series

Not Hydric


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Typic Aquisalids


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Unknown Series

Hydric


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Aquic

Quartzipsamments


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Unknown

Series

Not Hydric


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Oxyaquic Dystrudepts


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Paxton Series

Not Hydric


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Typic Humaquepts


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Birdsall Series

Hydric


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Vertic Argiaquolls


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Parnell Series

Hydric


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Argiaquic Argialbolls


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Tonka Series

Hydric


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Aeric Calciaquolls


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Hamerly Series

Not Hydric


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Aquic Haplorthods


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Sunapee Series

Not Hydric


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Aeric Alaquods


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Leon Series

Non-hydric phase


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Typic Endoaqults


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Othello Series

Hydric


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Typic Umbraqults


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Series Unknown

Hydric


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Chromic Epiaquerts


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Sharkey Series

Hydric


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Summary

Interpretation of Soil Taxonomic names inSoil Survey manuscripts provides another

tool for identifying hydric soils.Most useful off-site as part of preliminary

analysis

Also useful to identify potential problemhydric soils

soil taxonomynew

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