soils exam 1

whats the key difference between soil pore air and atmospheric air

soil pore air has less oxygen and more CO2 and Nitrogen due to microbial plant respiration

profile

vertical section of soil composed of multiple horizons from the ground to underlying rock

solum

O

regolith

loosely arranged material above bedrock including A

what are the names (letters) of all the soil horizons in order

O

what is found in the O horizon

Organic matter

what is found in the A horizon

surface horizon composed of minerals and organic matter

What is found in the E horizon

subsurface horizon

What is found in the B horizon

subsurface horizon

What is found in the C horizon

parent material

what materials is soil composed of

Minerals

Saprolite

a soft

Eluviation

leaching - the removal of soil material in suspension from a layer or layers of soil - can also be defines as loss or removal of soil by water (process that makes E horizon happen)

illuviation

the deposition of soil material from an upper horizon to a lower horizon - materials flowing to lower horizons because of water moving through the soil (process that makes B horizon happen)

the B horizon will be larger in what age of soil (old/young)

older

residuum

weathering occurring from a stationary parent rock

colluvium

material transported by gravity

alluvium

material transported by water

loess

sediment deposit from eolian dust

eolian dust

sediment distributed by wind

Silicate primary minerals

Calcium Plagioclase

where do extrusive igneous rocks originate from

what types of rock does it result in?

rapidly cooled volcanic activity

Basalt

small crystals finely textured

Where do intrusive igneous rocks originate from

what types of rock does it result in?

cools slowly within earths crust

Where do sedimentary rocks originate from

what types of rock does it result in?

product of weathered rock

where do metamorphic rocks originate from

what types of rock does it result in?

rocks transformed by high pressure and tectonic activity

characteristics of basalt (texture

primary mineral

characteristics of granite (texture

primary mineral

what is plagioclase

a group of feldspar minerals containing aluminosilicates of calcium/sodium

what are some primary minerals in basalt

Ca-plagioclase
Olivine
Pyroxenes (aguite)

what are some primary minerals in granite

Biotite
Quartz
K-plagioclase

what do coarsly textured rocks weather into

sand

what do finely textured rocks weather into

clay

what is weathering

The disintegration of primary minerals and the reformation of some of those dissolved minerals into new secondary minerals.

physical weathering

the physical disintegration of rock materials into smaller sizes resulting in an increase in surface area

chemical weathering

the dissolution and/or alteration of primary
minerals and the reprecipitation into secondary minerals ( ie. clays)

surface area increases relative to ___

volume

what happens during a hydration weathering reaction

water molecules bind to a mineral

what happens during a hydrolysis weathering reaction

water molecules split into H+ and OH-
and H+ replaces the K+ from the mineral structure

what happens during a dissolution weathering reaction

water can dissolve minerals by hydrating the cation and anion and disassociating them

what happens during an acid reaction

acids accelerate weathering by increasing
H+ activity in water

increasing surface area increases…

chemical reactivity

what are some properties of clay

very high specific surface

what happens during an oxidation-reduction reaction

minerals containing Fe

what happens during a complexation reaction

soil biological processes produce organic
acids (oxalic

what are the names of the minerals that are most susceptible to weathering

olivine

what are the names of the minerals that are the least susceptible to weathering

K-feldspar

what type of weathering turns parent material into clay

chemical weathering

what is desilication

the process where soluble silica is dissolved from silicate minerals by rain and other water

What degree of soil development do goethite

limonite

What degree of soil development do gibbsite and allophane have

11

What degree of soil development do kaolinite and halloysite have

10

What degree of soil development do montmorillonites have

9

What are some primary parent rocks

basalt

what are some secondary clay minerals

Aluminosilicate Clays!
Smectite (Ca-montmorillonite)
Kaolinite (AlSi)
Imogolite (AlSi)
Halloysite (AlSi)
Allophane (AlSi)

what are some secondary oxide minerals

Goethite (Fe)
Hematite (Fe)
Gibbsite (Al)
Ferrihydrite (Fe)

What are some secondary crystalline minerals

Smectite (Ca-montmorillonite)
Kaolinite (AlSi)
Halloysite (AlSi)
Goethite (Fe)
Hematite (Fe)
Gibbsite (Al)

what are some secondary amorphous minerals

Allophane (AlSi)
Ferrihydrite (Fe)
Imogolite (AlSi)

What does ClORPT stand for

Climate

What are the four soil forming processes

Additions

what are the two components that influence climate

temperature and precipitation

Which soil horizon is typically the largest in a tropical climate

B horizon

What factors influence topography/relief

Elevation

Whats an addition

organic matter

whats a transformation

alteration of soil constituents

whats a loss

leaching

whats a translocation

movement of soil materials
(dissolved and mineral) between horizons

pedon

a fundamental unit of soils

soil series

a group of polypedons all with similar characteristics

Entisol

a recent soil - weak development with only A and C horizon

inceptisols

minimal horizon development - only evident horizon is the B horizon

often occurs on steep slopes or alluvial settings

Andisols

Formed from volcanic ash - low density and high organic matter - high water holding capacity

minerology dominated by allophane

imogolite

Gelisols

permafrost!

Histisols

organic soil with low profile development - low bulk density and high water colding capacity

Folists

a unique type of histosols because they are formed in recent lava flows and are enriched in organic matter

Aridisols

Dry soils or soils characterized by water deficiency through most of the year.

Vertisols

Shrink and swell - high smectite count

Mollisols

soft and rich

Alfisols

halfway between ultisol and mollisol - developed in moist deciduous forest landscape (think minecraft) moderately leached

Ultisols

leached soil

Spodisols

highly weathered

Oxisols

highly weathered

Anthropic epipedon

similar to mollic

Folistic epipedon

thin organic layer saturated foer less than 30 cumulative days in a year

Histic

20-60 cm thick organic material overlying mineral soil

Melanic

black organic rich > 30 cm thick developed from volcanic ash

Mollic

mineral surface layer with dark color characteristic of high organic matter content (> 0.6% OC > 25 cm thick

Ochric

pale in color

Plaggen

black horizon developed from long-term manure additions

Umbric

same as mollic except BS < 50%

Albic

light colored eluvial horizons

argillic

subsurface accumulation of silicate clays.

Calcic

accumulation of carbonates.

Cambic

evidence of physical and chemical alteration