Soil formation processes and profiles.

Question 1

How do pedologists define soil?

Answer 1

A naturally occurring, unconsolidated, mineral or organic material at the earth’s surface that can support plant growth.

Question 2

What is the meaning of soil?

Answer 2

Soil is a complex system. The complex nature of the soil is revealed in its formation, development, application, and the services it lends to us. The more you know about it the more we learn about its complexity.

Question 3

What are the two types of weathering?

Answer 3

1. Physical weathering
2. Chemical (Biogeochemical)
   weathering

Question 4

What are the three types of rocks?

Answer 4

Igneous, Metamorphic, and Sedimentary.

Question 5

How are igneous rocks formed?

Answer 5

They are formed from molten magma.

Question 6

What are igneous rocks made up of?

Answer 6

They comprise primary minerals (Minerals already present in the magma).

Question 7

What are the three categories of primary minerals?

Answer 7

Quarts, Light-colored minerals, Dark-colored minerals.

Question 8

What is the difference between dark colored and light colored minerals when it comes to weathering?

Answer 8

Dark-colored minerals are more easily weathered compared to light colored minerals.

Question 9

How are sedimentary rocks formed?

Answer 9

They are formed by the accumulation or deposition of mineral or organic particles at Earth’s surface.

Question 10

What is the most common type of rock found on earth?

Answer 10

Sedimentary rock. It covers about 75% of the earth’s land surface.

Question 11

What are the three types of sedimentary rocks?

Answer 11

Clastic, Biochemical, Chemical.

Question 12

How are clastic sedimentary rocks formed?

Answer 12

They are formed from the joining of pre-existing materials like sand, clay, and silt.

Question 13

How are biochemical sedimentary rocks formed?

Answer 13

Formed from shells and bodies of underwater organisms.

Question 14

How are chemical sedimentary rocks formed?

Answer 14

Water collects minerals and then redeposites somewhere else. Once the water evaporated the mineral residue is left.

Question 15

How are metamorphic rocks formed?

Answer 15

Metamorphic rocks are formed from other rocks (igneous, sedimentary or other metamorphic) that go through a change.

Question 16

How do metamorphic rocks compare to sedimentary rocks?

Answer 16

Metamorphic rocks are usually harder and more strongly crystalline than sedimentary rocks that they form from.

Question 17

What is physical weathering?

Answer 17

The physical breakdown of rocks.

Question 18

What can cause physical weathering?

Answer 18

1. Intensity of physical weather
2. Temperature change
3. Abrasion by water, ice, and wind.
4. Plants and animals.

Question 19

What does Chemical (Biochemical) weathering do?

Answer 19

It alters the original minerals.

Question 20

How is chemical weathering enhanced?

Answer 20

It is enhanced by the presence of water and oxygen and also by the acids produced by microbials and plant-root metabolism.

Question 21

What are the three important characteristics of surface conditions that lead to chemical weathering?

Answer 21

1. Presence of water
2. Abundance of O2
3. Presence of CO2

Question 22

What is Hydrolysis?

Answer 22

This is when the original mineral becomes altered to a different mineral.

Question 23

What are the 5 factors that influence soil formation and practices?

Answer 23

1. Time
2. Topography
3. Parent material
4. Climate
5. Plants and animals

Question 24

What kinds of soils do Quarts rich and Quarts poor soils produce?

Answer 24

Quarts rich produce lots of sandy soil and Quarts poor produce little sandy soils.

Question 25

What are the two characteristics of soil influenced by the parent material?

Answer 25

1. Soil texture 2. Chemical and mineralogical composition of soil.

Question 26

What is residual parent material?

Answer 26

This is the soil produced from parent material that stays at the same spot as the parent material.

Question 27

What are lacustrine soils?

Answer 27

Soils transported by water and deposited in lakes.

Question 28

What are Alluvial soils?

Answer 28

Soils transported by water and deposited by streams.

Question 29

What are Marine soils?

Answer 29

Soils transported by water and deposited in oceans.

Question 30

What are Colluvial soils?

Answer 30

Soils transported by gravity.

Question 31

What are Till and Moraine soils?

Answer 31

Soils transported by ice and deposited by ice.

Question 32

What are Outwash soils?

Answer 32

Soils transported by ice and deposited by water.

Question 33

What are Eolian soils?

Answer 33

Soils transported by wind and deposited by wind.

Question 34

What are the two factors that are a part of climate and influence soil formation? How do they affect soil formation?

Answer 34

1. Effective precipitation 2. Temperature They affect the rates of chemical, physical and biological processes.

Question 35

What is meant by effective precipitation?

Answer 35

Water that goes through the soil. ~ 80% of water goes through soils that are not compromised.

Question 36

What are two things water must do to promotes soil development?

Answer 36

1. Water must enter the soil profile and participate in weathering reactions. 2. Water must seep through the profile and translocate soluble weathering products.

Question 37

How does too much or too little water affect the soil?

Answer 37

Too much water leads to leaching of the soil making the soil acidic. Too little water results in very little downward chemical transportation and leads to accumulation of salts and minerals on the surface.

Question 38

How does temperature and evaporation influence how much water percolates through the soil?

Answer 38

In hot areas with high evaporation water may lead to salt accumulation whereas in cold climates with low evaporation leaching of the soil is likely to occur.

Question 39

How does permeability influence how much water percolates through the soil?

Answer 39

For example: Sandy soils will experience more effective penetration because water infiltrates through it more easily. This leads to more rapid soil development.

Question 40

What are the 4 things that influence how much water percolates through the soil?

Answer 40

1. Temperature and evaporation 2. Precipitation 3. Permeability 4. Topography

Question 41

How happens for every 10 degree rise in temp?

Answer 41

Biochemical reactions more than double.

Question 42

What four processes are maximized with the rise of temp.?

Answer 42

1. Weathering 2. Leaching 3. Biological activities 4. Plant Growth.

Question 43

What kind of a process is soil development?

Answer 43

It is a continuous interactive process.

Question 44

What are the two things weathering is dependent on?

Answer 44

1. What kind of a rock it is 2. Mineral contained in the rock and it's resistance to weathering.

Question 45

Are dark-colored minerals or light-colored minerals weathered more easily?

Answer 45

Dark-colored minerals because they contain iron and magnesium which are easily weathered.