Soils Exam II

Question 1

What are the best suited purpose of each USDA land capability class? (I, II, V, and VII)

Answer 1

I - All
II - Intensive cultivation (some limitations)
V - No cultivation, intensive grazing

Question 2

What are the 12 soil orders?

Answer 2

Andisol, Histosol, Vertisol, Entisol, Inceptisol, Ultisol, Oxisol, Aridisol, Gelisol, Mollisol, Alfisol, Spodosol

Question 3

Soil order ending in “…ands”

Answer 3

Andisols

Question 4

Soil order ending in “…ists”

Answer 4

Histosols

Question 5

Soil order ending in “…erts”

Answer 5

Vertisols

Question 6

Soil order ending in “…ids”

Answer 6

Aridisols

Question 7

Soil order ending in “…els”

Answer 7

Gelisol

Question 8

Soil order ending in “…olls”

Answer 8

Mollisols

Question 9

Soil order ending in “…alfs”

Answer 9

Alfisols

Question 10

Soil order ending in “…ods”

Answer 10

Spodosols

Question 11

What is the bulk density of most mineral soils in temperate regions that are not compacted?

Answer 11

1.2 g/cm3

Question 12

What is Volumetric water content?

Answer 12

The volume of water per volume of soil

Question 13

Features of Andisols

Answer 13

Poorly cystaline clays and glass dominated
Volcanic PM
High Water holding capacity

Question 14

Features of Histosols

Answer 14

20-30% Organic Matter by weight

Not a mineral soil

Question 15

Features of Vertisols

Answer 15

Rich in clay
Highly susceptible to shrink/swell
Has deep cracks up to several inches wide (when dry)

Question 16

Features of Entisols

Answer 16

No B horizon

Little or no soil development present

Question 17

Soil order ending in “…ents”

Answer 17

Entisols

Question 18

Soil order ending in “…epts”

Answer 18

Inceptisols

Question 19

Features of Inceptisols

Answer 19

Has weak B horizon

Relatively young soil

Question 20

Soil order ending in “…ults”

Answer 20

Ultisols

Question 21

Features of Ultisols

Answer 21

Highly leached and weathered
Acidic forest soils
Quite old soil

Question 22

Soil order ending in “…oxs”

Answer 22

Oxisols

Question 23

Features of Oxisols

Answer 23

Contains only Oxide minerals
Not found in WA
Tropic locations

Question 24

Features of Aridisols

Answer 24

Contains large amounts of CaCO3
Some subsurface horizon development
Dry most of the year

Question 25

Features of Gelisols

Answer 25

Has permenant permafrost | Not found in WA

Question 26

Features of Mollisols

Answer 26

Dark, thick A horizon | Grassland locations

Question 27

Features of Alfisols

Answer 27

Moderately leached Broadleaf forests High fertility and water holding capacity Clay accumulation (Bt)

Question 28

Features of Spodosols

Answer 28

accumulation of sdsquioxides (Al and Fe) Bs horizon present Sandy Coniferous and acidic forests

Question 29

Channeled Scablands formation

Answer 29

Shaped by catastrophic floods from northern regions

Question 30

Large eruption about 8000 years ago

Answer 30

Mount Mazama

Question 31

Define Particle Density

Answer 31

Mass of particles (or solids) per volume of particles (or solids)

Question 32

Estimated Bulk Density for mineral soil in temperate regions

Answer 32

1.2 g/cm3

Question 33

Which pores are most important for air movement in soil?

Answer 33

Macropores

Question 34

Why is good aggregation important?

Answer 34

Increases soil porosity Increases number of Macropores Increases easy movement of air and water

Question 35

What measurement is used to quatify the shrink-swell tendency of soils?

Answer 35

Coefficient of Linear Extensibility (COLE)

Question 36

What will water do if Soil A = -300kPa and Soil B = -500kPa

Answer 36

Move from soil A to soil B

Question 37

What components of total water potential effects water flow direction in a saturated Soil?

Answer 37

Gravitational and pressure potential

Question 38

The components of total water potential

Answer 38

Pressure Potential Gravitational Potential Osmotic Potential Matric Potential

Question 39

Difference between Adhesion and Cohesion

Answer 39

Adhesion - Attraction of water to soilds | Cohesion - Attraction of water to water

Question 40

What conditions must be present for Osmotic pressure to also be present?

Answer 40

A semi-premeable membrane and solutes

Question 41

How to quantify field capacity

Answer 41

Approximately at -30kPa | Moist, well drained soil

Question 42

How does OM help with compaction?

Answer 42

Reduces compaction | Increases aggregate stability