Soils Intro

Question 1

What is soil

Answer 1

the soilic material on the Earth’s surface that results from the interaction of weathering and biological activity on the parent material/ hard rock

Question 2

How is soil made?

Answer 2

from the interaction of weathering and biological activity on the parent material/ hard rock

Question 3

Why study soil?

Answer 3

Helps understand wildlife activity, potential and conservation for both plants and animals

Question 4

What are the 4 principles of soil

Answer 4

Water
CO2 sequestration (storage)
Water holding
water purification

Question 5

If there is less than 50% air and water in soil what does this mean?

Answer 5

It is poor soil

Question 6

What percentage of soil is typically humus/ organic matter?

Answer 6

3-5%

Question 7

What % of soil is sand?

Answer 7

10%

Question 8

What % of soil is clay

Answer 8

22%

Question 9

What % of soil is air?

Answer 9

25%

Question 10

What % of soil is water?

Answer 10

25%

Question 11

What % of soil is silt?

Answer 11

15%

Question 12

What 7 things comprise soil?

Answer 12

water
air
humus
silt
clay
sand
living organisms/ component

Question 13

Name 3 components of organic matter?

Answer 13

• Cellulose
• Hemicellulose
• Lignin
• Protein
• Fats, waxes

Question 14

Name 3 sources of organic matter for agricultural soils

Answer 14

• Crop residues
• Bulky organic manures
• Sewage sludge -
• Green manure
• Composted urban waste
• Rotational practice (stubble)

Question 15

What are the horizontal layers of soil known as?

Answer 15

Horizons

Question 16

What are the A, B and C horizons?

Answer 16

A - top soil
B - Subsoil
C - Parent soil

Question 17

What is the structure of soil horizons (5)

Answer 17

Humus
top soil
subsoil
parent material 
bedrock

Question 18

Where can the O horizon be found?

Answer 18

above top soil in forests

Question 19

what is the o horizon?

Answer 19

organic matter (humus)

Question 20

Which is the most important nutrient in soil?

Answer 20

Nitrogen

Question 21

Which horizon is nitrogen mainly found?

Answer 21

humus layer - O horizon

Question 22

Name 3 ways soils can be formed

Answer 22

Earth movement - earthquakes etc
Changes in sea levels
Volcanic activity
Retreat of glaciers

Question 23

What are the 3 types of weathering/ erosion that can cause soil formation?

Answer 23

Physical
Chemical
Biological

Question 24

Give an example of physical, chemical and biological weathering

Answer 24

Physical = freeze/ thaw, wet/dry, hot/cold, abrasion
Chemical = water disolving rock - i.e: acid dissolution in limstone
Biological - tree roots cracking rocks, earthworms mixing materials, dead organic matter

Question 25

What are the 5 factors of soil formation?

Answer 25

``` Organisms Time Topography (distribution/ arrangement of the area) Climate Parent material ```

Question 26

Which is the most important factor in soil formation?

Answer 26

Climate

Question 27

How does climate affect soil formation?

Answer 27

Affects rate / type of soil vegetation distribution - therefore nutrient content precipitation (moisture content) Temperature - evaporation rate (and vegetation growth, nutrients etc)

Question 28

What conditions lead to leaching?

Answer 28

When precipitation exceeds evaporation

Question 29

What is leaching

Answer 29

the loss of water-soluble nutrients in soil

Question 30

What do micro and macro organisms do?

Answer 30

Micro (bacteria) - help decompose plant litter | Macro (worms, beetles etc) mix litter into soil

Question 31

What influences the nature of humus, vegetation, litter etc

Answer 31

higher plants

Question 32

What are 4 benefits of roots in soil

Answer 32

contribute to dead organic material bind soil particles together redistribute and compress soil Remove nutrients

Question 33

What are macrobiota

Answer 33

the living organisms of a region that are large enough to be seen with the naked eye i.e: ants, termites, earthworms, beetles, snails, wasps, milipedes

Question 34

What are mesobiota?

Answer 34

the intermediate size of soil organisms | i.e: o Springtails, mites, pseudo-scorpions (false scorpion)

Question 35

What are microbiota?

Answer 35

bacteria, archaea, protists, fungi, viruses, yeast, cyanobacteria (blue-green algae)

Question 36

How do cyanobacteria help soil health?

Answer 36

Fixes nitrogen in soil

Question 37

Which organism helps fix nitrogen in soil

Answer 37

Cyanobacteria

Question 38

How does topography influence soil formation?

Answer 38

slopes - influence soil thickness, nutrients, erosion, run-off, movement, microclimatic conditions

Question 39

How does time influence soil formation?

Answer 39

Soil takes time to form | More time = more nutrients, features and materials can be added to help formation

Question 40

what are the 5 processes of soil formation

Answer 40

1) weathering 2) decomposition and humification 3) capillary action - when evaporation exceeds precipitation (reverse leaching) 4) leaching 5) Translocation

Question 41

What is decomposition

Answer 41

the breakdown of plant dervived material into its simpler organic constituents – accomplished by enzymes, earthworms, mites and other organisms

Question 42

What is humification

Answer 42

the breakdown of plant remains leading to the formation of different types of humus

Question 43

What is the most important BIOLOGICAL PROCESS in soils?

Answer 43

humification

Question 44

What are 3 types of humus

Answer 44

Mull Moder Mor

Question 45

Where are mull, moder and mor found

Answer 45

Mull - deciduous woodland Moder - intermediate Mor - coniferous woodland or heather moorland (wet, climatic conditions)

Question 46

Which type of humus is found in deciduous and coniferous woodland?

Answer 46

Deciduous - mull | coniferous - mor

Question 47

Why is leaching bad for soil?

Answer 47

It removes soluble minerals

Question 48

Which types of soils have more leaching?

Answer 48

sandy soils - because they are more porous

Question 49

What is translocation?

Answer 49

the movement of material in solution or suspension from one horizon to another

Question 50

What happens in the Eluvial horizon?

Answer 50

where maximum leaching (or eluviation) takes place – the horizon that loses the minerals

Question 51

What is the illuvial horizon?

Answer 51

- Lower horizon that gains the material - maximum accumulation happens

Question 52

What does white soil indicate?

Answer 52

quartz or salts

Question 53

What does red soil indicate

Answer 53

Iron oxide accumulation

Question 54

what does brown or black soil indicate

Answer 54

type and level of organic matter

Question 55

What colour will poorly drained gleys be

Answer 55

grey / blue-grey

Question 56

what does grey/ blue colour soil indicate?

Answer 56

Poor drainage with anaerobic conditions (no O2) - usually gleys

Question 57

What causes soil colouration?

Answer 57

oxidation - reduction

Question 58

What is the texture of loam soil?

Answer 58

A combination of sand, silt and clay

Question 59

Put in order of size: silt, sand, clay

Answer 59

Clay - smallest Silt - intermediate Sand - biggest

Question 60

Name 3 ways texture affects soil

Answer 60

- Soils ability to hold water - Soils ability to hold and supply plant nutrients - Suitability for different plant species - Trafficability of the land, and the ability to support structures - Macro and micro fauna that live in the soil

Question 61

What are the 4 types of soil texture

Answer 61

Sand Clay Silt Loam