Chapter 5- Weathering Soils

Question 1

What is weathering?

Answer 1

The process by which rocks are broken down into smaller particles.

Question 2

What are the two main types of weathering?

Answer 2

Mechanical weathering and chemical weathering.

Question 3

True or False: Mechanical weathering involves the physical breakdown of rocks without changing their chemical composition.

Answer 3

True

Question 4

What is the primary agent of chemical weathering?

Answer 4

Water

Question 5

What is the process where rocks and minerals dissolve in water?

Answer 5

Dissolution

Question 6

Which type of weathering involves the action of plants and animals breaking down rocks?

Answer 6

Biological weathering

Question 7

What are the three main types of soil particles?

Answer 7

Sand, silt, and clay

Question 8

True or False: Sandy soils have large particles and drain water quickly.

Answer 8

True

Question 9

What type of soil particle is the smallest and has the best water retention?

Answer 9

Clay

Question 10

What is the process where soil particles are carried away by water or wind?

Answer 10

Erosion

Question 11

Which horizon of the soil profile contains the most organic matter?

Answer 11

O horizon

Question 12

What is the layer of soil where roots grow and nutrients are taken up by plants?

Answer 12

Topsoil

Question 13

What is the process where minerals are dissolved in water and taken up by plant roots?

Answer 13

Nutrient uptake

Question 14

What is the measure of the acidity or alkalinity of soil?

Answer 14

Soil pH

Question 15

True or False: Soil pH affects the availability of nutrients to plants.

Answer 15

True

Question 16

What is the term for the process where soil becomes compacted and loses its ability to hold water and nutrients?

Answer 16

Soil compaction

Question 17

Which soil texture has the best water retention and nutrient availability?

Answer 17

Loam

Question 18

What is the process where soil particles settle into distinct layers based on size and density?

Answer 18

Soil stratification

Question 19

True or False: Soil fertility refers to the ability of soil to support plant growth.

Answer 19

True

Question 20

What is the process where soil nutrients are replenished through the decomposition of organic matter?

Answer 20

Nutrient cycling

Question 21

What is the term for the removal of soil nutrients faster than they can be replenished?

Answer 21

Soil depletion

Question 22

Which type of soil has the highest nutrient content and best water retention?

Answer 22

Humus-rich soil

Question 23

True or False: Soil erosion can lead to loss of topsoil and decreased soil fertility.

Answer 23

True

Question 24

What is the process where soil particles are carried downhill by the force of gravity?

Answer 24

Mass wasting

Question 25

Pressure release

Answer 25

Removal of overlaying rock allows expansion and fracturing. (Exfoliation domes)

Question 26

Frost action

Answer 26

Mechanic effect of freezing (and expanding) water on rocks. Frost wedging and frost heaving.

Question 27

Other types of mechanical weathering

Answer 27

-plant growth (tree roots) -thermal variation (large temperature changes fracture rocks by repeated expansion and contraction) -salt pressure -Burrowing animals

Question 28

A horizon

Answer 28

Dark colored, rich in organic matter and high in bio activity

Question 29

E horizon

Answer 29

Zone of leaching; fine grained material removed by percolating water

Question 30

B horizon

Answer 30

Zone of accumulation; clays and iron oxides reached down from above; forms *hard pan* in wet climates

Question 31

C horizon

Answer 31

Partially weathered bedrock

Question 32

Residual Transported

Answer 32

-weathering of underlying rock -brought in from elsewhere wind-transported soil is called *Loess*

Question 33

Soil composition

Answer 33

Determined by parent rock comp evolves with time and chemical weathering.