Soil Resources

Question 1

List 5 soil forming factors

Answer 1

1. Parent Material
2. Organisms
3. Climate
4. Topography
5. Time

Question 2

The process when rocks physically disintegrate and chemically decompose

Answer 2

Weathering

Question 3

Physical weathering

Answer 3

The processes that cause rocks to disintegrate into smaller particles by some mechanical means (ex: plant roots, freezing/thawing rocks,
confining pressure…)

Question 4

Chemical Weathering

Answer 4

The process where individual mineral grains within a rock decompose due to chemical reactions.

Question 5

Why does climate play an important role in chemical weathering?

Answer 5

Because many of the chemical reactions involving rock forming minerals are affected by temperature and the presence of water.

Question 6

The mineral ______________ is resistant to chemical weathering.

Answer 6

Quartz

Question 7

Name 2 silicates that weather to form clays.

Answer 7

1. Feldspar
2. Ferromagnesian silicate minerals

Question 8

Horizontal layers within the soil zone that form as the result of chemical and biological processes and physical transport of material vertically within the soil.

Answer 8

Soil Horizons

Question 9

List the 6 soil horizons in order from top to bottom

Answer 9

O
A
E
B
C
R

Question 10

Describe soil horizon O

Answer 10

~Loose and partly decayed organic matter
~Blackish brown color due to decaying plant matter

Question 11

Describe soil horizon A

Answer 11

~Mineral matter mixed with some hummus
~Blackish brown color due to decaying plant matter

Question 12

Describe soil horizon E

Answer 12

~Zone of eluviation and leaching
~Appear whitish or blonde because they lack pigmenting materials (oxide minerals have been leached and transported downward by infiltrating water)

Question 13

Describe Soil Horizon B

Answer 13

~Accumulation of clay, iron and aluminum from above, zone of illuviation and known as zone of accumulation
~Exhibit a range of colors because they represent the zone where various oxide materials accumulate withing the soil profile. The specific color of B horizons varies on the presence of free oxygen.
~The color of B horizon is a useful indicator as to the level of drainage and saturation within a soil.

Question 14

Describe soil horizon C

Answer 14

Partially altered parent material

Question 15

Describe soil horizon R

Answer 15

Unweathered parent material, bedrock

Question 16

In addition to horizons, other important soil characteristics are color, structure and _________.

Answer 16

Texture

Question 17

Is soils classified loam or sandy loam considered to be a better agricultural soil? And why?

Answer 17

Loam since they provide the best combination of drainage and fertility.

Question 18

A soil characteristic that refers to the way in which the soil particles themselves are arranged.

Answer 18

Soil Structure

Question 19

What is peds or aggregates?

Answer 19

When previously undisturbed soil is dug up, it will naturally break up into separate clumps that can take on different shapes.

Question 20

What is the soil classification system used by scientists?

Answer 20

Soil Taxonomy

Question 21

What 2 things is soil taxonomy based on?

Answer 21

1. Characteristics of the horizons found in particular soil
2. Soil’s temperature and moisture regime

Question 22

The engineering classification of soils is based on ___________________ properties.

Answer 22

physical

Question 23

Name the 7 Soil Properties

Answer 23

1. Porosity
2. Soil moisture and drought resistance
3. Permeability
4. Plasticity
5. Compressibility
6. Shrink-swell
7. Ion exchange capacity

Question 24

What is cohesive vs. adhesive forces?

Answer 24

Cohesive: Same molecules attracted to each other, such as water attracted to water through hydrogen bonding
Adhesive: One substance attracted to another substance, such as water attracted to the glass

Question 25

Texture refers to the amount of ________, _________________, and ________-________ material within a particular horizon,

Answer 25

sand, silt and clay-sized material

Question 26

Name 2 specific ways is soil used as a resource?

Answer 26

1. Farming 2. Several important mineral and energy resources (aluminum, bauxite)

Question 27

Why is teh loss of organics in soil loss so important?

Answer 27

Organics and clay minerals are what make the soil so rich in the first place.

Question 28

Name the 9 soil mitigation techniques.

Answer 28

1. contour plowing 2. Strip cropping 3. No till farming 4.Grassed waterways 5. Terracing 6. Stream buffers 7. Silt fencing 8. Retention basins 9. Slope vegetation cover

Question 29

What is a paleosol?

Answer 29

A soil sequence that has been buried during some geologic event, representing a distinct time marker that can be useful in scientific investigations.