Horizons Flashcards
The Four Processes
Losses, additions, transformations, and translocations
The Five Factors of Soil Formation
Parent material, climate, time, organisms, and slope
Transport of parent materials by water is called…
alluvium
Transport of parent materials by gravity is called…
coluvium
Transport of parent materials by lake beds drying up is called…
lacustrine
Transport of parent materials by wind is called…
aeolian
Transport of parent materials by ocean is called…
marine
Transport of parent materials by retreating glaciers is called…
glacial till
Transport of parent materials by glaciers melting is called…
glacial outwash
Alluvium is found…
in floodplains and terraces
Colluvium is found…
at footslopes
Lacustrine is found…
in dried-up lake beds
Aeolian is found…
in windblown deposits or dunes
Marine is found…
in exposed ocean deposits
Glacial till is found…
in broad glacial plains
Glacial outwash is found….
in areas within glaciated areas
Alluvium is identifiable by being…
sandy/silty with no B
Colluvium is identifiable by…
being similar to soils uphill
Lacustrine is identifiable by…
silty/clayey
Aeolian is identifiable by…
sandy or silty
Marine is identifiable by…
mixed sands and clays
Glacial till is identifiable by…
mixed sandy/silty
Glacial outwash is identifiable by…
sand/gravel deposits
Highly decomposed litter forms the ___ horizon.
Oa
Partially decomposed litter (usually with fungi about) forms the ___ horizon.
Oe
Slightly decomposed litter that is still identifiable forms the ___ horizon.
Oi
Dark soils with an abrupt boundary high in the profile forms the ___ horizon.
Ap
Dark soils deeper in the horizon than normal forms the ___ horizon.
Ab
A horizons are dark due to
humus content
Eluvium forms the ___ horizon.
E
Illuvial humus with blocky structure and a high Fe content forms the ___ horizon.
Bh
Illuvial clay, usually called “clay films”, with a blocky structure and high Fe content forms the ___ horizon.
Bt
Illuvial Fe present in clay with a blocky structure forms the ___ horizon.
Bw
A blocky structure of Fe that has been gleyed (has a chroma of 2 or less) forms the ___ horizon.
Bg
Visible rock in the bottom layer of soil forms the ___ horizon.
Cr
Gleyed soils with a massive structure forms the ___ horizon.
Cg
The solum consists of horizons…
A, E, and B
The regolith consists of the horizons…
A, E, B, and C
Saprolite is ________ and occurs in the __ horizon.
weathered parent material; C
A thick and dark A with a Munsell value of 2 or less and a high amount of basic cations (Ca, Mg, and K)
Mollic
Deep and dark A that is more acidic
Umbric
Peat and muck A horizons, more resembling an O
Histic
Light-colored or shallow A horizons
Ochric
B horizon with a blocky structure, illuvial Fe, but no illuvial clay.
Cambic
B horizon with illuvial clay and typically has high Fe content. Has a well-developed blocky structure
Spodic
B horizon with lots of illuvial clay and Fe; very thick, and typically only found in the tropics
Oxic
Ochric or umbric over argillic - mature soils without much leeching yet
Alfisol
Desert soils; soluble salts in solum
Aridisol
Volcanic ash parent material
Andisols
Ochric or umbric A over C with no B; extremely young soils
Entisols
Cold climates with permafrost
Gelisols
Ochric or umbric over Bw - still pretty young
Inceptisols
