Soil forming rocks and weathering

Question 1

What are the soil forming factors according to Dokuchaiev and Hans Jenny?

Answer 1

Climate, organisms, parent material, topography, and time

CLORPT: S = f(c, o, r, p, t)

Question 2

What are the two groups of soil forming factors?

Answer 2

Active: Climate + organisms; Passive: Parent material, topography, time

Question 3

What is the process of true soil formation from regolith?

Answer 3

Formation occurs through the combined effect of soil forming factors and processes

Question 4

What term describes a sequence of soils that differ due to climate?

Answer 4

Climosequence

Question 5

What is a lithosequence?

Answer 5

A group of adjacent soils differing in certain profile properties due to differences in parent material

Question 6

Define residual parent material.

Answer 6

Develops in place from underlying rock and experiences long, intense weathering

Question 7

Define transported parent material.

Answer 7

Loose sediments that have been transported by gravity, ice, or wind

Question 8

What are the transporting agents and their associated soil deposits?

Answer 8

• Water: Alluvium, Lacustrine, Beach deposit
• Wind: Loess, Colluvium, Sand dune
• Gravity: Glacial Ice

Question 9

How does parent material influence soil properties?

Answer 9

Influences soil texture, chemistry, and mineralogy

Question 10

What is the effect of texture on soil?

Answer 10

Determines the rate of air and water movement (permeability) and the amount of water held in the soil

Question 11

What are the two most important climate variables affecting soil formation?

Answer 11

Temperature and precipitation

Question 12

How does precipitation influence soil weathering?

Answer 12

Affects water movement in the soil profile and extent of weathering

Question 13

True or False: Soils in humid environments tend to be less weathered.

Answer 13

False

Question 14

What happens to soils in wet humid climates?

Answer 14

Increased weathering, leaching, and accumulation of CaCO3 at deeper depths

Question 15

How does temperature influence soil formation?

Answer 15

Affects the rate of mineral weathering and biological processes

Question 16

What is a biosequence?

Answer 16

A sequence of soils that contain distinctly different soil horizons due to major influence of organisms

Question 17

What role do organisms play in soil formation?

Answer 17

• Addition of organic matter
• Nutrient cycling
• Prevent soil erosion
• Form soil structure

Question 18

How do grassland soils differ from forest soils?

Answer 18

• Grassland: Thick A horizon, low acidity, low leaching
• Forest: Thin A horizon, thick O horizon, high acidity

Question 19

What is the role of macrofauna in soil?

Answer 19

• Ingestion of organic matter
• Profile mixing
• Increase aeration through burrowing

Question 20

What is the significance of the human factor in soil formation?

Answer 20

Profound changes in soil cover due to agriculture, machinery use, and urban development

Question 21

What does topography refer to in soil formation?

Answer 21

The shape of the land surface, including slope and aspect

Question 22

How does time affect soil formation?

Answer 22

Influences the contribution of soil forming factors and extent of pedogenetic reactions

Question 23

What is the impact of slope aspect on soil development?

Answer 23

• South facing: warmer, drier, less vegetation
• North facing: cooler, moister, greater vegetation

Question 24

Fill in the blank: A ________ is a contiguous array of soils that differ due to climate.

Answer 24

climosequence

Question 25

Fill in the blank: A __________ influences soil properties through factors like ploughing and fertilization.

Answer 25

human factor

Question 26

What is the relationship between time and soil development?

Answer 26

The more developed the soil will be. ## Footnote Time affects all other soil forming factors.

Question 27

What does the weathering of minerals give rise to?

Answer 27

Weathering sequences. ## Footnote Weathering processes are crucial for soil formation.

Question 28

How can climate affect soil over time?

Answer 28

Some soils have been affected by more than one climate. ## Footnote This highlights the dynamic nature of soil formation.

Question 29

What are the primary effects of relief on soil?

Answer 29

Uplift, downwearing, and erosion of surfaces. ## Footnote Relief influences the physical characteristics of soils.

Question 30

What does vegetation succession lead to?

Answer 30

A climate climax community. ## Footnote Vegetation types can indicate soil stability and health.

Question 31

What is the significance of time in soil development?

Answer 31

Not a reflection of the years soil had been developing. ## Footnote Age and degree of maturity are based on horizon differentiation.

Question 32

What factors influence horizon differentiation in soils?

Answer 32

The intensity of soil forming processes. ## Footnote This includes climatic and biological factors.

Question 33

How do arid regions differ from humid regions in terms of soil age?

Answer 33

Chronologically old soils may be developmentally young in arid regions; old soils in humid regions are often developmentally mature. ## Footnote Water availability plays a crucial role in soil development.

Question 34

When are time-related differences most evident in soils?

Answer 34

For stable surfaces. ## Footnote Time is a less significant factor for depositional and erosional surfaces.

Question 35

What is a chronosequence in soil science?

Answer 35

A sequence of related soils that differ primarily as a result of time that pedogenic processes have been occurring. ## Footnote Chronosequences help in understanding soil development over time.

Question 36

What is an example of a chronosequence?

Answer 36

Soil development over time in humid forested conditions. ## Footnote O and A horizons can form very quickly compared to Bt horizons.

Question 37

What is pedogenesis?

Answer 37

The relationship between soil forming factors and processes. ## Footnote Understanding pedogenesis is fundamental to soil science.

Question 38

What do soil forming factors integrate to create?

Answer 38

Unique and varied soil profiles with distinctive horizons. ## Footnote This diversity is essential for ecosystem function.