Soils

Question 1

What is the general structure of soil?

Answer 1

45% Minerals
25% Water
25% Oxygen
5% Organic Matter

Question 2

What are the functions of soil?

Answer 2

Support plant life
Habitat
Storage, filtration and transportation of substances

Question 3

What is the name of the different soil profiles in order of top to bottom?

Answer 3

Organic Material, Surface, Subsoil, Parent Material

Question 4

Why is it sometimes difficult to distinguish the different layers of the soil profile?

Answer 4

Because they are typically merged together through different processes

Question 5

What is the scientific word for soil formation?

Answer 5

Pedogenesis

Question 6

Why is soil formation regarded as a non-renewable resource?

Answer 6

Because for soil to form takes thousands of years

Question 7

What are the two inputs of soil formation?

Answer 7

Mineral weathering, which is the influence of minerals from the bedrock and other sources.
Organic Matter, which is biomass above and below the surface

Question 8

What are the outputs of soil formation?

Answer 8

Erosion (water and wind)

Leaching

Question 9

What is leaching?

Answer 9

Flushing of nutrients through the soil layers due to extensive precipitation.

Question 10

What causes mixing in the soil formation process?

Answer 10

Bioturbation from small and large organisms.

Leaching

Question 11

What causes transformation in the soil formation process?

Answer 11

Decomposition and chemical processes can alter the state of the soil.

Question 12

What are two chemical process that can transform the soil?

Answer 12

Oxidation, Dissolving

Question 13

What can causes chemical processes?

Answer 13

Precipitation and leaching

Question 14

How does climate affect soil formation?

Answer 14

Climate determines temperature, which in turn affects the rate of certain processes, precipitation, wind erosion

Question 15

How does topography and hydrology affect soil formation?

Answer 15

Soils located at the bottom of a valley will receive a lot of water from various flows and runoffs. The gradient also determines the ability of water to infiltrate down in to the soil.

Question 16

Define fertility

Answer 16

The ability of the plant to support vegetation

Question 17

What are the 7 factors that affect a soil’s fertility?

Answer 17

Water, Air, Organic Matter, Minerals and Nutrients, Texture, Structure, Porosity

Question 18

How can soil texture change?

Answer 18

It can range from fine clay particles all the way to sand

Question 19

How can soil structure change?

Answer 19

It can range from structureless to prismatic then to platy

Question 20

Define porosity

Answer 20

The measure of how much air is in the soil. If something is porous then it has a lot of air within it

Question 21

What is the wilting point?

Answer 21

The point when the plant’s water levels are insufficient enough to cause GPP to fall to its minimum

Question 22

what is filed capacity?

Answer 22

The point when the plant has ideal water levels that GPP is at its peak.

Question 23

What happens when the plant’s water levels exceed the amount in its field capacity?

Answer 23

Over-saturation meaning that the GPP starts to decline.

Question 24

Why is air important for soil fertility?

Answer 24

Air is important within soils because it allows the plant roots to breathe

Question 25

What is the perfect balance between water and air within soils?

Answer 25

50:50 usually (25% and 25% respectively)

Question 26

Why are nutrients and minerals important for soil fertility?

Answer 26

They assist with various processes that vegetation is involved with such as the nitrogen cycle and phosphorus cycle.

Question 27

What does it mean if something is more bioavailable?

Answer 27

It is easier for plants to access either because it is available at a wider range of PH levels or it is more abundant at a specific PH level.

Question 28

What are the various ways/mediums that plants can receive/extract nutrients and minerals from the soil?

Answer 28

Solution (micronutrients) Absorbed to clay and organic matter Inside organic molecules Inside mineral structure

Question 29

What are 6 human impacts upon the soil?

Answer 29

``` Contamination Acidification Salinization Compaction Loss of organic matter Erosion ```

Question 30

What is compaction?

Answer 30

forcing the soil to become more compacted and thereby reduce its porosity. This can be caused by heavy machinery or from overgrazing.

Question 31

How is organic matter lost from agricultural practices?

Answer 31

When the crop is extracted from the soil the organic matter is not recycled back in to the soil instead is taken with the yield.

Question 32

How can agricultural practices increase erosion?

Answer 32

Forest clearance, overgrazing, poor management, biomass burning.

Question 33

What is salinization?

Answer 33

Increasing the salt content of the soil

Question 34

What is contamination and acidification?

Answer 34

Inputting various chemcials such as fertilisers and weed killers that can cause the soil to become enriched with various solutions altering its PH

Question 35

what things does soil texture determine?

Answer 35

Drainage, water-holding capacity, temperature, aeration, chemical properties

Question 36

What is storage capacity?

Answer 36

The total amount of water soil can hold

Question 37

What is capillary water?

Answer 37

Water held in pores <0.05mm in diameter. This water supply forms the bulk of water available to plants in soil