Organic horizon, saturated for less than 30 days per normal year
Very high in organic content, wet during some part of the year
Thick, black, high in organic matter (>6% organic C), common in volcanic ash
Thick, dark-colored, high base saturation (>50%), strong structure
Too light-colored, low organic content or thin to be Miollic, may be hard and massive when dry
Human-made sodlike horizon created by years of manuring
Same as Mollic except low base saturation (<50%)
Agric (A or B)
Organic and clay accumulation just below plow layer (6-8")
Light-colored, clay and Fe and Al oxides mostly removed
Silicate clay accumulation
Accumulation of CaCO3 or CaCO3*MgCO3
Cambic (Bw, Bg)
Changed or altered by physical movement or by chemical reactions, generally nonilluvial
Hard pan, strongly cemented by silica
Brittle pan, usually loamy textured, dense, coarse prisms
Whitish eluvial horizon that tongues into a Bt horizon
Accumulation of gypsum
Accumulation of low-activity clays
Argillic, high in sodium, columnar or prismatic structure
Highly weathered, primarily mixgture of Fe, Al oxides and nonsticky-type silicate clays
Cemented clacic horizon
Cemented gypsic horizon
Thin pan cememnted with iron alone or with manganese or organic matter
Accumulation of salts
Organic matter accumulation
Spodic (Bh, Bs)
Organic matter, Fe and Al oxide accumulation
Highly acidic with Jarosite mottles
What is the major feature or characteristic that distinguishes the plaggen and anthropic from the other epipedons?
How many acres are in a township?
How many sections in a township?
1 square mile each
1 square mile = 640 acres
Categories of Soil Taxonomy, from broadest to most specific?
Define soil phase
A subdivision of the series, it narrows down properties used in farm planning
no naturally formed horizons (or just beginning)
high content of swelling clays
master horizons dominate
mild weathering, various conditions
soft, dark soils
must have Mollic epipedon
50% base saturation
semi-arid to moist grasslands
moderately weathered soils
argillic/natric diagnostic horizon
>35% base saturation (no mollic, oxic, spodic horizon)
old weathered soils
most soluble materials leached out
argillic horizon <35% base saturation
(strongly acid clays)
usually high in salts
Ash colored soils
must have a spodic horizon
high organic matter
measured by amount of decomp
ice or permafrost
volcanic ash materials
not much profile development
a vertical section of the soil through all its horizons and extending into the parent material
a layer of soil, approximately parallel to the soil surface, differing in properties and characteristics from adjacent layers below or above it
having lost all or part of the upper soil horizon or horizons
horizons having specific soil characteristics that are indicative of certain classes of soils. horizons that occur at the soil surface are called epipedons. those that occur below the surface are diagnostic subsurface horizons
a soil layer or horizon in which material carried from an overlying layer has been precipitated from solution or deposited from suspension. The layer of accumulation.
the removal of soil material in suspension from a layer or layers of a soil. usually, the loss of material is described by the term leaching.
a mapping unit used in detailed soil surveys where two or more defined taxonomic units are so intimately intermixed geographically that it is undesirable or impractical, because of the scale being used, to separate them.
grouping of soils found together in a geographical area
consists of 2 or more soil series
a group of soils that commonly occur together in a landscape, each characterized by a different slope position and resulting set of drainage-related properties
the smallest volume that can be called a soil. it has three dimensions. it extends downward to the depth of plant roots or to the lower limit of the genetic soil horizons. its lateral cross section is roughly hexagonal and ranges from 1 to 10 m2 in size depending on the variability in the horizons.
not limited to 2mm diameter
fine-silty, loamy, coarse loamy, clayey, skeletal, etc.
dominant clay in system
kaolinitic,, montmorellonitic, mixed, etc.
semiactive, active, superactive
messic - 8-15C, 46-59F
thermic - 15-22C, 59-72F
hyperthermic - above 72, 22C
acidic, calcareous, neutral
the "unofficial" category, or the workable part of taxonomy
What is used as the mapping unit in MO soil surveys?
5 randomly assigned numbers
You'd use this, along with the soil survey, as a starting point for developing farm plans, to i.d. and develop erosion control practices or if you were a county assessor
Land Capability Classification System
What would class 1 be in the Land Capability Classification System?
few, if any limitations on land use (good crop land)
If land falls into the class range of 1-3 under the Land Capability Classification System, what would it be suitable for?
row crop cultivation
2-3 more sloped than 1
Class 4 for Land Capability Classification System?
marginally suited for cultivation
Class 5 for Land Capability Classification System?
limitation is something other than slope
frequent overflow, large rocks or boulders
Classes 6-8 in Land Capability Classification System?
several use limitations
6-7-8 increasing slopes
8, maybe watershed areas, aesthetic values
Land capability subclasses?
e - erosion hazard
w - water
s - soil limitation (usually impermeable layer)
c - climatic factor
What type of land area description would you likely find east of the Mississippi River?
metes and bounds
creeks, fored road, trees
what type of land area description would you find west of the Mississippi River?
Rectangular survey system based on areas with square corners
Principal meridian runs
North - South
T1N, T2N, T3N, principal meridian, T1S, T2S
6 mile intervals
Base line is in Arkansas, south of Little Rock
R29W, R28W, R20W...
A township is how many miles squared?
how many acres in a quadrant?
when measuring chroma, is a higher or lower value indicative of a grayer soil?
lower the value, grayer the soil
value measures blackness. if a soil was absolutely black, what value would it have?
0= absolute black
the shape of soil agregates
long axis parallel to the surface (kind of oval shaped)
soil structure - subangular/blocky
corners may be rounded, but sort of cube-shaped
more blocky as clay content increases
soil structure - angular blocky
almost perfect cube shaped
faces flat, edges sharp
flat tops, axis perpendicular to the soil surface. like little towers.
axis perpendicular to the soil surface but rounded tops
most common soil structures in mo?
granular, subangular, angular blocky
extremely high clay content and particles fuse together
when the plow or till can break it apart easily
Old horizon designation was O. New?
Old designation was O1 or O2. New?
O1 - Oi, Oe
O2 - Oa, Oe
Old designation A. New?
What is the first mineral horizon?
In the old designation, transition zones were indicated with a capital letter and a number. What do the new transitions look like?
Two capital letters
Old designation A1. New?
Old designation A2. New?
Old designation A3. New?
AB or EB
Old designations A & B?
Old designations AC. New?
Old designation B. New?
Old deisgnation B1. New?
BA or BE
Old designation B2. New?
B or Bw
Only use Bw when no other subordinate is appropriate.
So if we have B2t, what do we use? Bt2
Old designation is B3. New?
BC or CB
In the old designations, roman numerals signify change in parent materials. How is that indicated now?