Soils

1
Soils A lecture for G10. Created by Bob
Hall Revised 10/8/2001
2
Weathering profiles at Cagles Mill
3
CONCEPT OF THE WEATHERING PROFILE
DEFINITIONS 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..
4
Weathering profiles at Cagles Mill
5
CONCEPT OF WEATHERING PROFILE
(CONT.)INCLUDES NOT JUST THE SOIL, BUT ANY
NEAR-SURFACE MATERIAL AFFECTED BY
WEATHERING.FOR UPPER MIDCONTINENT OF N.
AMERICA PARENT MATERIAL IS ORIGNALLY
CALCAREOUS (GLACIAL, EOLIAN, ETC.)
6
Weathering profiles at Cagles Mill
7
MIDCONTINENT WEATHERING PROFILE
8
Weathering profiles at Cagles Mill
9
SOIL PROFILE LAYERED UPPER PART OF THE
WEATHERING PROFILE RESULTING FROM ALTERATION OF
PARENT MARERIAL 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.

• THE SOIL PROFILE
• DEFINITIONS

10
0 A E B C D R


O
A
A
EB
B
B
C
C
D
D
R
11
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

12
(No Transcript)
13
(No Transcript)
14
(No Transcript)
15
SOIL HORIZONS

• O LARGE AMTS ORGANIC MATTER
• A HUMUS AND MINERAL MATTER
• E LOW IN CLAY, SESQUIOXIDES
• B ACCUM. OF CLAY, SESQUIOXIDES
• C SLIGHTLY WEATH. PAR. MATERIAL
• D UNWEATHERED PARENT MATERIAL
• R BEDROCK

16
0 A E B C D R


O
A
A
EB
B
B
C
C
D
D
R
17
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 VEG.

18
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)

19
FACTORS OF SOIL FORMATIONS or s f
(cl,o,r,p,t..)

• S the soil s any soil property
• cl climate precipitation and temperature
• 0 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??

20
STOP

• If you dont need soil classification.
• Go to slide 26.

21
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

22
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

23
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

24
SOIL CLASSIFICATIONRELEVANT TABLES IN TEXT
25
SOIL CLASSIFICATIONAN EXAMPLE (CONT.)

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

26
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

27
SOIL-FORMING FACTORS (CONT.)

• PODZOLIZATION (CONT.)
• NORTH
• SPODOSOLS, ALFISOLS
• COLDER, MORE ORG. MATTER
• SOUTH
• ULTISOLS
• WARMER, LESS ORG. MATTER, MORE OXID.

28
SOIL-FORMING FACTORS (CONT.)

• LATERIZATION
• TROPICAL CONDITIONS
• ORGANICS OXIDIZED
• SILICA LEACHED
• 11 CLAYS OR HYDRATED AL OXIDES AND HYDROXIDES
• OXISOLS

29
SOIL-FORMING FACTORS

• CALCIFICATION
• DRY CIMATES
• CALCIUM CARBONATE ACCUM.
• DEPTH RELATED TO PRECIPITATION
• SUBHUMID TO SEMIARID
• MOLLISOLS
• ARID ARIDISOLS

30
PALEOSOLS

• SOILS THAT FORMED ON A PAST LANDSCAPE
• TYPES
• BURIED
• WELDED GROUND SOIL MERGED WITH IT
• EXHUMED
• RELIC

31
PALEOSOLS (CONT.)

• IMPORTANCE
• INFLUENCE ON GROUND SOIL DEVELOPMENT
• STRATIGRAPHIC CORRELATION
• RECONSTRUCTION OF PALEOCLIMATE, VEGETATION