SCSC 301 Exam 3 Review

Epipedon

diagnostic SURFACE horizon (A, O)

Endopedon

dignostic SUBSURFACE horizon (E, B)

diagnostic horizon

horizons with specific properties that help with classification

moisture regime

classify soils ability to supply plants with water

temperature regime

classify soils mean annual temperature

map unit

collection of area that have the same soil components

area of interest

region that you identify to evaluate soil properties; usually a single managed unit

epipedons

mollic, umbric, ochric, histic

mollic

A, dark, thick, soft, HIGH bases

Umbric

A, dark, thick, soft, LOW bases

Ochric

A, light or dark, shallow

Histic

O, dark, thick, organic

Albic

E, white

Cambic

Bw, new B horizon, no illuviation yet

Argillic

Bt, high bases

Kandic

Bt, low bases

Oxic

Bo, oxides

Spodic

Bhs, humus and oxides leached below an E horizon

Calcic

Bk, carbonates

Petrocalcic

Bkm, carbonates, massive

Gypsic

By, gypsum

Petrogypsic

Bym, gypsum, massive

Salic

Bz, salts

Natric

Btn, clay, sodium

Duripan

Hardpan, cemented by Si

Fragipan

Brittle hard pan

Alfisol

argillic, Bt

Andisol

Volcanic materials

Aridisol

Bk, Bz, By, or Btn, arid climate

Entisol

No B

Gelisol

permafrost

Histosol

Histic, O (deep), organis > 1m

Inceptisol

Cambic, Bw

Mollisol

mollic

Oxisol

Oxic, Bo, tropical climate

Spodosol

spodic, Bhs

Utisol

Kandic, Bt (low bases)

Vertisol

mollic, argillis, maybe Bt (high bases), slickensides, shrink/swell clays, high clay

development of soil orders

E, HIGAn, Ar, V, MAl, SU, O

aquic

saturated

udic

High moisture year-round

ustic

Semi-arid climate

aridic

arid climate

xeric

dry

hyperthermic

above normal temperature

mesic

moist

frigid

very cold

cryic

icy cold

gelic

permafrost

thermic

average

steps of erosion

detachment, transportation, deposition

splash erosion

the impact of falling raindrops breaking up the clumpy structure of the topsoil

water erosion

when streams, river, and oceans cut into the land wearing away the soil and rocks moving them elsewhere.

sheet erosion

water flows over a layer of soil and removes the topsoil

rill erosion

water running down the side of a slope carves a small stream channel

gully erosion

removal of layers of soil, creating channels or ravines too large to be removed by normal tillage operations

water erosion control

-vegetative cover

-residues

-conservation tillage

-contour cultivation

-strip cropping

-terraces

-grassed waterways

wind erosion

when the wind picks up dirt and dust and moves it from one place to another

suspension erosion

fine particles are moved into the atmosphere (and eventually return to earth) by strong winds

saltation erosion

Wind causes small soil particles to move along the soil surface in a bouncing fashion

creep erosion

the slow downhill movement of weathered rock material

wind erosion control

Soil moisture

Conservation tillage

Wind barriers (shelter belts)

Universal Soil Loss Equation

A=RKLSCP

A=RKLSCP

A = annual soil loss R = rainfall K = erodibility L = slope length S = slope steepness C = crop cover P = practices to prevent erosion

Wind Erosion Equation

E=ICKLV

E=ICKLV

E = annual soil loss I = erodability factor C = climate K = surface roughness L = field width V = vegetation

Conservation Reserve Program

U.S. policy in farm bills since 1985 that pays farmers to stop cultivating highly erodible cropland and instead place it in conservation reserves planted with grasses and trees.