Soil

composed of minerals, gases, water, organic substance, microorganisms

Soils

complex natural systems of material and interacting components

O horizon

organic material in varying decay states

A horizon

topsoil, enriched with organic matter, dark brown ish

E horizon

Not always there, intense leaching

B horizon

sub soil, decomposition/weathering, rusty brown, clay iron and/or OM

C horizon

unweathered parent material

Soil porosity

proper drainage & retention

Soil structure

arrangement of solid particles and pore space

Water holding capacity

ability to store water

Aeration

ability to exchange o2 levels

Colloids

electrostatic charge to attract/absorb nutrient ions --> buffering capacity

carbon cycle implication

store carbon in diff amt depending on veg and climate

Physical weathering ex

freeze/thaw, abrasion, heat/cool

very cold/very hot climate

chemical weathering ex

dissolution, oxidation/reduction

wet and hot climate

biological weathering example

plant secreting acids, root expansion

igneous

cooling of molten material, basalt at top, granite at bottom

sedimentary

accumulation of sediments by chemically or compression

metamorphic

igenous/sedimentary rock altered by heat, pressure, or chem activity

glacial deposits

basal till, glacio-fluvial outwash, glacio-lacustrine

Basal till

beneath advancing glacier, dense, poorly sorted, restricted drainage

glacio-fluvial outwash

moving melt water, loose, coarse, well sorted, excellent permeability

glacio-lacustrine

fine layers of alternating silt and clay

higher temps vs colder temps

higher temps have faster chem reactions

excess rainfall

low cations so more acidic

little rainfall

leached cations so alkaline

translocation

material being moved within soil

transformation

material being altered

R layer

bedrock

Mollic Epipedon

dark with organic matter, rich in Ca and Mg

Umbric Epipedon

same as mollic but with less Ca and Mg

Ochric Epipedon

pale, little OM

Histic Epipedon

OM over mineral soil

Argillic horizon

accumulate silicate clays, illuvated

albic horizon

light colored eluviated horizon w low clay and fe/al oxides

spodic horizon

illuviated with collodial OM and Al oxides

cambic horizon

non sandy horizon w some weathering

gelisols

got permafrost

aridisols

too dry for mesophytic plants

aridisols

pale, low OM, little moisture

alfisols

weathered, leaches clay

ultisols

humid regions, intense weathering

spodosols

coarse texture, weathering leaches OM

tundra

cold temp, limited water, short grow season

gelisols

temperate deciduous forests

plants, water exceeds evapotranspiration of plants, OM bc shedding leaves

alfisols and inceptisols

coniferous forests

cold temp, high elevation, short grow season

spodosols

temperate grassland

grass dominated, mollisols, fertile, neutral to alkaline pH

temperate deserts

dry, aridisols, pale

tropical rainforests

hot, humid, oxisols, high NPP

Which is hue, value, chroma

10YR 5/6

YR: hue

5: value

6: chroma

infiltration

water entering soil

percolation

water moving thru soil

water hold capacity

ability to store water

bulk density

dry wt/vol

porosity

100 - [BD/Pd * 100]

aeration drainage issues occur when...

porosity <40%

smaller pores

more suctional force

gravitational water

drains out of large pores via gravity

Capillary Water

held in the medium and fine pores against the force of gravity, cohesion

soil moisture %

aka GMC

[wet-dry]/dry * 100

volumetric moisture

aka VMC

GMC - [BD/density water]

PAW

Moisture content of field - moisture content at wilting

endoaquatic

watertable at or near surface

epiaquatic

accumulated above impermiable layer

spontaneous flow goes from...

high potential to low potential

potential energy state of water equation

SUM of the gravitational potential, the matric potential (if unsaturated) or the hydrostatic potential (if submerged), and the osmotic potential