Soils

Front 1

5 soil forming factors

Back 1

climate

organisms

relief

parent material

time

Front 2

regolith

Back 2

materials on the earth's surface above solid rock

soil and subsoil

Front 3

water processes

Back 3

alluvium

lacustrine

marine

Front 4

water + ice processes

Back 4

glacio-fluvial

glacio-lacustrine

Front 5

ice processes

Back 5

morainal

Front 6

wind processes

Back 6

eolian

loess

Front 7

gravity processes

Back 7

colluvium

Front 8

3 categories of PM

Back 8

igneous

sedimentary

recent cover deposits

Front 9

soil structure

Back 9

how the soil particles are aggregated

defines nature of the system of pores and channels in soil

greatest effect on porosity, soil moisture, air relations

Front 10

soil texture

Back 10

particles (sand, silt, clay)

defines the specific surface area

OM and clay are cement between particles + encourage formation of peds

Front 11

cohesion

Back 11

intermolecular attraction to like molecules

Front 12

adhesion

Back 12

intermolecular attraction between unlike molecules

binds water to other surfaces

Front 13

surface tension

Back 13

causes water on glass to form bubbles

stronger than adhesion

Front 14

factors that contribute to water behaviour

Back 14

gravity

pressure

solute

matric forces

Front 15

soil water holding capacity

Back 15

charged water molecules can bind with charged soil particles

Front 16

soil colloid

Back 16

soil particle suspended in water

Front 17

hydraulic conductivity

Back 17

measurement of the ability of water to move through soil

Front 18

saturation point

Back 18

when soil cannot hold any more water

Front 19

field capacity

Back 19

amount of water remaining in soil after downward drainage has slowed or stopped

-max amount of water usable by plants

Front 20

gravitational water

Back 20

water that is not held by charge after water drains

Front 21

permanent wilting point

Back 21

point at which plant roots can no longer remove water from soil

Front 22

hygroscopic water

Back 22

water left in soil past the permanent wilting point

-a fine film bound by electrical charges not available to plants

Front 23

available water

Back 23

water between field capacity and the permanent wilting point

Front 24

infiltration

Back 24

downward entry of water into soil

Front 25

percolation

Back 25

water movement through the large and medium pores by the forces of gravity

macropores

Front 26

capillary action

Back 26

water movement within the small pores of soil

micropores

Front 27

matric suction

Back 27

pressure that dry soil exerts on the surrounding soils to equalize the moisture content in the overall block of soil

Front 28

wetting front

Back 28

pattern that forms from moving water, influenced by percolation and capillary action

Front 29

saturated flow

Back 29

soil pores filled with water. gravitational and relatively constant

Front 30

unsaturated flow

Back 30

when soil is below a saturated state governed by matric forces and not a constant factor

Front 31

water movement in layered soils

Back 31

layering impedes water movement, water + plants tend not to move through layers, water will move readily coarse to fine

Front 32

perched water table

Back 32

body of water above water table in the unsaturated zone that doesn't drain, caused by fine over coarse

Front 33

porosity

Back 33

amount of airspace in soil

Front 34

total porosity

Back 34

total amount of airspace in soil

Front 35

aeration porosity

Back 35

% of air space after all gravitational water is removed

Front 36

water holding porosity

Back 36

total porosity - aeration porosity

Front 37

measuring bulk density

Back 37

bulk density = mass / volume