CONCEPT OF THE WEATHERING PROFILE

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CONCEPT OF THE WEATHERING PROFILE

• Weathering Zone Zone of Alteration Differing
  Physically, Chemically, or Mineralogically from
  Adjacent Zones, and Extending Laterally Beneath
  the Land Surface.
• Weathering Profile Vertical Assemblage of
  Weathering Zones from the Land Surface to and
  Into the Unweathered Parent Material.

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CONCEPT OF WEATHERING PROFILE

• Includes Not just the Soil, but any Near-surface
  Material Affected by Weathering.
• For Upper Midcontinent of North America Parent
  Material is Originally Calcareous (Glacial,
  Eolian, Etc.)

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MIDCONTINENT WEATHERING PROFILE
I Eluviated, organic, deeply weathered, leached
of carbonates, oxidized II Illuviated,
inorganic, deeply weathered, leached of
carbonates, oxidized III Not strongly
weathered, leached, oxidized IV Not strongly
weathered, unleached, oxidized V Unaltered
parent material, unleached, unoxidized
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THE SOIL PROFILE

• Soil Profile Layered Upper Part of the
  Weathering Profile Resulting from Alteration of
  Parent Material by Primarily Biochemical
  Processes.
• Layers Better Known as Soil Horizons.
• Soil Profile Coincides with Zones I and II and
  the Upper Part of Zone III of the Weathering
  Profile.

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THE SOIL PROFILE

• Criteria for Distinguishing Major Soil Horizons
• Organic Content Amount and Type of Veg.
  Preservn Chelation Water Absorption Carbonic
  Acid
• Color
• Soil Texture
• Soil Structure

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SOIL HORIZONS

• O Large Amounts Organic Matter
• A Humus And Mineral Matter
• E Low In Clay, Sesquioxides
• B Accumulation Of Clay, Sesquioxides
• C Slightly Weathering Parent Material
• D Unweathered Parent Material
• R Bedrock

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TYPES OF A HORIZONS

• MOLLIC Dark, gt 1 Organics, gt 50 Base
  Saturation
• Usually Developed Under Grass.
• UMBRIC Dark, gt 1 Organics, lt 50 Base
  Saturation
• Usually Developed Under Forest.
• OCHRIC Light, lt 1 Organics
• Usually Developed Under Semiarid Vegetation.

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TYPES OF B HORIZONS

• ARGILLIC High in Clay (Textural B)
• NATRIC High in Exchangeable Sodium
• SPODIC High in Organics and Sesquioxides
• OXIC High in 11 Clays, Hydrated Oxides of Fe
  and Al
• CAMBIC Oxidized to Red (Color B)

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FACTORS OF SOIL FORMATIONS or s f
(cl,o,r,p,t..)

• S the soil s any soil property
• cl climate precipitation and temperature
• o biota vegetation usually predominant
• r topography position on a slope affects soil
  drainage, soil erosion slope aspect also
• p parent material
• t time duration
• independent factors??

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SOIL CLASSIFICATIONLOWER LEVELS

• Soil Series Soils with Similar Profiles because
  of Same or very Similar Parent Materials. Example
  Miami Series (P.M. Wisconsinan Till)
• Soil Type Subdivision of Series Based on Range
  of Textures. Examples Miami Silt Loam, Miami
  Sandy Clay, Miami Clay Loam

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SOIL CLASSIFICATIONHIGHER LEVELS

• 11 Orders Distinguished by Diagnostic Horizons
• Suborders Named for Diagnostic Physical or
  Chemical Property Prefix that Property Suffix
  Reflects Order
• Great Groups and Subgroups More Detailed
  Properties

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SOIL CLASSIFICATIONAN EXAMPLE Humodic cryudent

• ent entisol (order) a soil with a
  weakly-developed, A-C profile, little or no
  clay accumulation
• ud udic (suborder) moist and has low to
  moderate organics

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SOIL CLASSIFICATIONRELEVANT TABLES IN TEXT

• T3.8/69 Formative Elements of Orders of USDA
  System
• T3.7/68 Orders and Suborders
• T3.9/70 Naming Suborders
• T3.10/70 Naming Great Soil Groups
• Also Useful 3.13/69

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SOIL CLASSIFICATIONAN EXAMPLE

• cry cold (great group)
• odic sodic B horizon Hum weakly developed
  (subgroup)
• Try one yourself.

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CLIMATE AND VEGETATION AS SOIL-FORMING FACTORS

• Podzolization
• Humid, Temperate Climates
• Forest Vegetation
• Acidic Conditions
• Removal of Bases
• Translocation of Fe, Al (Primarily By Chelation)
• Creation of E Horizon

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SOIL-FORMING FACTORS

• Podzolization
• North Spodosols, Alfisols Colder, More Organic
  Matter
• South Ultisols Warmer, Less Organic Matter,
  More Oxidation

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SOIL-FORMING FACTORS

• Laterization
• Tropical Conditions
• Organics Oxidized
• Silica Leached
• 11 Clays or Hydrated Al Oxides and Hydroxides
• Oxisols

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SOIL-FORMING FACTORS

• Calcification
• Dry Cimates
• Calcium Carbonate Accumulation, Depth Related To
  Precipitation
• Subhumid to Semiarid Mollisols
• Arid Aridisols

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PALEOSOLS

• Soils that Formed on a Past Landscape
• Types
• Buried Welded Ground Soil Merged with it
• Exhumed
• Relic

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PALEOSOLS

• Importance
• Influence on Ground Soil Development
• Stratigraphic Correlation
• Reconstruction of Paleoclimate, Vegetation