Chapter 2 - Soil origin and classification

Question 1

Igneous Rock

Answer 1

Solidified, molten lava; slow to break down

Question 2

Sedimentary Rock

Answer 2

Formed from particles that settle, such as from minerals deposited from suspension in water

Question 3

Metamorphic Rock

Answer 3

Formed from other rocks, such as continental plates moving and other pressures; tends to create stronger rock (granite, slate)

Question 4

Weathering

Answer 4

Chemical and physical breakdown and/or synthesis of particles

Question 5

Biogeochemical Weathering

Answer 5

Weathering by

• water
• oxygen
• biological agents
• acids and bases (H+, OH-) produced by micro org and plant roots

Question 6

Factors influencing soil formation

Answer 6

1) Parent material
2) Climate
3) Biota
4) Topography
5) Time

Question 7

Soil formation - parent material

Answer 7

Formed in place or moved to a new location

Question 8

Residual Parent Material

Answer 8

Developed in place from underlying rock

Weathered and breaks apart

Question 9

Colluvial Materials

Answer 9

Rock fragments that are above a deposit of soil

Rocks carried down a slope - gravity

Question 10

Alluvial Materials

Answer 10

Moved by water
Flood plains, delta deposits, coastal sediment
Ice movement (glaciers)

Question 11

Eolian Movement

Answer 11

Wind
One of the biggest movers of soil
Builds dunes and loess
Volcanic ash

Question 12

Loess

Answer 12

Silt-sized particles moved by wind

Question 13

Organic deposits - examples/attributes

Answer 13

Marshes, swamps
Slow degradation
Creates peat

Question 14

Soil formation - climate: factors

Answer 14

Precipitation/moisture (including humidity) - needed for most chemical reactions
Seasonal rains
Evaporation
Leaching
Hydrolysis
Temperature

Question 15

Hydrolysis chemical reaction

Answer 15

Addition of H2O to make a reaction occur to break down material
Ex: starch (carbohydrates) + H2O -> breaks down into glucose(s)

Question 16

Soil formation - biota

Answer 16

living organisms, microorganisms (bacteria, fungus)

Question 17

Grassland characteristics

Answer 17

• Deep OM, grass roots
• Less acidic
• Main recycler: bacteria

Question 18

Forest characteristics

Answer 18

• Surface OM
• More acidic
• Recycler: fungus

Question 19

Macro-organism (worms) functions in soil

Answer 19

• Aerate
• Worm castings - fertilize
• Mucus helps soil bind together

Question 20

Pedoturbation

Answer 20

Organisms mixing the soil (turning “peds”)

Question 21

Soil formation - topography

Answer 21

Slopes, valleys, flatlands, depressions

Question 22

Soil formation - time

Answer 22

Time of aging

Question 23

Basic Soil Formation Process (4 steps)

Answer 23

1) Transformation - physical and chemical weathering, breakdown & synthesis
2) Translocation - movement of soil, any direction
3) Additions - water, OM, soil via wind
4) Losses - leaching, erosion, grazing, crops, evaporation, wind