using soil taxonomy to identify potential hydric soils · soil taxonomy a basic system of soil...
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Using Soil Taxonomy Using Soil Taxonomy to Identify Potential to Identify Potential
Hydric SoilsHydric Soils
Soil Taxonomy
A basic system of soil classification for making and interpreting soil surveysObjective: To develop a hierarchical classification that
reflects the relationships between different soils, and between soils and the factors responsible for their character.
Soil Taxonomy
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 other disciplines (e.g., soil temperature and moisture regimes inferred from soil science and meteorology).
Soil Taxonomy
Series
Family
Sub Group
Great Group
Sub OrderFirst sign of wetness
Order12 Orders
Entisol
Fluvent
Ustic
Mollic
Fine-loamy, mixed, frigid
Korchea
Fine-loamy, mixed (calcareous), frigid,Mollic Ustifluvent (Korchea series, western ND)
Soil Taxonomy
Nature ofNumber Differentiating
Category of Taxa Characteristics
Order 12 Soil-forming processesas indicated by presenceor absence of majordiagnostic horizons
Soil Orders
• Inceptisols• Mollisols• Oxisols• Spodosols• Ultisols• Vertisols
• Alfisols• Andisols• Aridisols• Entisols• Gelisols• Histosols
Dominant Soil Orders
AlfisolsAndisolsAridisolsEntisolsGelisolsGel/Inc (AK)HistosolsInceptisolsMollisolsOxisolsSpodosolsUltisolsVertisols
Taxonomic NamesSoil OrderAlfisolAndisolAridisolEntisolGelisolHistosolInceptisolMollisolOxisolSpodosolUltisolVertisol
Name Ends in:-alf-and-id-ent-el-ist-ept-oll-ox-od-ult-ert
Entisol Suborders
• Aquents(L. Aqua, Water)Wet Entisols
• Fluvents(L. Fluvius, River)Floodplain Soils
• Orthents(Gr. Orthos, True)The Typical Ones
• Psamments(Gr. Psammos, Sand)Sandy Soils
Examples of Entisol Great Groups
• SuborderAquents(Wet Entisols)
• Great GroupsCryaquents - coldFluvaquents - floodplainHydraquents - waterPsammaquents - sandEpiaquents - perched
Examples of Entisol Great Groups
• SuborderFluvents(Floodplain
soils)
• Great GroupsTorrifluvents - torrid
(hot and dry)Tropofluvents - tropical
(warm and humid)Udifluvents - humid
(not dry in most years)Ustifluvents - semi-arid
(between Udic-Aridic)Xerofluvents - semi-arid
(Mediterranean climate)
Examples of Entisol Great Groups
• SuborderPsamments(Sandy Soils)
• Great GroupsCryopsammentsQuartzipsamments -
QuartzTorripsammentsUdipsammentsUstipsammentsXeropsamments
Interpreting Taxonomic Names
Subgroup - Great Group, Suborder, Order4 3 2 1
Vertic Udifluvent• 4 - Vertic subgroup - invert, shrink-swell, high clay• 3 - Udi(c) great group - humid climate• 2 - Fluv(ic) suborder - floodplain• 1 - Ent(isol) order - little soil development
Aquic Soil Moisture Regimes
• Typic subgroup of an aquic suborder:• Typic ____aqu____
– wettest• Aeric subgroup of an
aquic suborder:• Aeric ____aqu____
– better aerated• Aquic subgroup:
• Aquic ___________– driest From Mausbach 1992
Examples of Subgroups
4 3 2 1Typic Fluvaquents
4 1 2Typical Entisols with aquic moisture regimes
3that occur on floodplains.
1. Order 3. Great Group2. Suborder 4. Subgroup
Examples of Subgroups4 3 2 1
Mollic Fluvaquents
1 2Entisols with aquic moisture regimes that
3 occur on floodplains and have thick,
4dark surface layers.
1. Order 3. Great Group2. Suborder 4. Subgroup
Examples of Subgroups4 3 2 1
Aeric Fluvaquents
1 3 2Entisols on floodplains with aquic moisture
regimes that are not so wet. They are better4
aerated in the “upper” part of the soil profile.
1. Order 3. Great Group2. Suborder 4. Subgroup
Soil TaxonomyNature of
Number DifferentiatingCategory of Taxa Characteristics
Series 15,000+ May have virtually the full range ofproperties that is permitted in a family, but in one or more propertiesthe range is restricted, such as:- Kind and arrangement of horizons- Color- Texture- Structure
Typic Medisaprists
Typic Medisaprists
Terric Haplosaprists
Terric Haplosaprists
Lithic Cryofolists
Lithic Cryofolists
Aquic Paleudalfs
AquicPaleudalfs
Aquic Glossudalfs
AquicGlossudalfs
Typic Aquisalids
Typic Aquisalids
AquicQuartzipsamments
AquicQuartzipsamments
Typic Humaquepts
Typic Humaquepts
Typic Argiaquolls
Typic Argiaquolls
Argiaquic Argialbolls
Argiaquic Argialbolls
Aeric Calciaquolls
Aeric Calciaquolls
Aeric Alaquods
Aeric Alaquods
Typic Umbraqults
Typic Umbraqults
Chromic Epiaquerts
ChromicEpiaquerts