a group of pedons that share the same soil properties

a collection of soil areas defined and named the same in terms of their soil components

a horizon that forms at or near the surface and in which most of the rock structure has been destroyed. It is darkened by organic matter.

What determines how deep epipedon extends into the soil profile?

oxidized iron

reduced iron

these soils shrink when dry, swell when wet

has a very high percentage of organic matter

this soil is formed from ash, pumice, and ejecta

this soil is the most weathered of all soil orders

subsoil permanently frozen

peds

amount of adhesion between soil particles

particles less than 0.001 mm in diameter

size of particles

No B horizon, young soils

B horizon just beginning to form

subsurface horizon of silicate clays, base saturation < 35%

subsurface horizon of silicate clays, base saturation >35%

minerals are not leached out

albic/spodic horizons

high activity clay with shrinking and swelling

prairie soils

inactive clay with no shrinking or swelling

surface horizon with lots of organic matter, base saturation less than 50%

surface horizon with little organic matter, low base saturation due to little vegetation

thin surface horizon, with muck or peat below

surface horizon with volcanic ash, light and fluffy

surface horizon with lots of organic matter, base saturation greater than 50%

Most common, inactive clays

active clays that shrink/swell

Which of the following are basic cations

Which soil orders are grouped by climate?

Which of the following are grouped by parent material

Amount of cations a soil can hold:

Which soil orders are found in missouri?

What are the three most common found in MO

which is only found in swamps in MO

Which is only found along river floodplains in MO

Compaction increases

Which includes pore space and solids

breakdown of peds happens by:

Processes that form peds

Ways to reduce compaction

Why do sands have higher bulk density?

ground contact pressure only compacts

contact pressure and axle load only compacts

axle load ONLY compacts

Compaction reversed in 5 years

Compaction reversed in 10 years

Compaction is permanent, never reversable

Soils that are water saturated long enough to reduce iron and effect plant growth

When iron is ___ it loses an iron oxide coating, like M&M

types of pores:

made by worms, beetles, etc.

types of pores:

in between ped pieces (but all in one ped)

types of pores:

spaces between particles

Which soil particle never has intraped pores?

Which soil particle has macropore sized packing pores

which soil particles have microsized packing pores

minerals are carried downward by acidic water to horizon B

When minerals are deposited and accumulate in B horizon

Where in the soil profile would an eluvial zone be located

Where in the soil profile would an illuvial zone be located

What are the requirements for a soil to be hyrdic

smaller than .001 mm in diameter

surface area 10,000 times more than sand

two basic types of compaction

zone of accumulation

zone of reduction

wavy, dark horizon in spodosols

ashy, light colored horizon in spodosols

secondary soil colors present in a horizon

dominant soil color. over 50% of soil

caused by Fe in water logged soils

color patterns in a soil that are caused by loss or gain of Fe

usually filled with water

too small to permit air movement

larger pores accommodate root hairs

air easily moves through

water moves quickly by gravity

roots readily penetrate

formed by biological processes

formed by physical or chemical processes