Geoecology - Soil Flashcards
(113 cards)
1
Q
What is soil
A
The layer of natural material on the earths surface that is capable of supporting plant growth
2
Q
How much of earth surface is made up of soil
A
25%
3
Q
How much of the earths soil can support the growth of food
A
10%
4
Q
What is the study of soil called
A
Pedology
5
Q
What are the 5 component of soil
A
Mineral matter (45%) Air (25%) Water (25%) (Living organisms Humus) = organic matter (5%)
6
Q
What is mineral matter made up of
A
Small pieces of rock broken down by weathering and Erosion
7
Q
What two components of air are essential for plants and microorganism living in soil
A
Oxygen
Nitrogen
8
Q
What does water have to benefit plants
A
Nutrients
9
Q
Examples of living organisms in soil
A
Earthworms, slugs, Woodlice
Microorganisms eg bacteria and fungi
10
Q
Function of organisms in soil
A
Break down dead plants to create humus
Help mix humus into soil particles by loving and loosening soil particles enabling water to get through
11
Q
What is humus
A
Decaying organic matter eg plants, animals, leaves, grass
12
Q
Function of humus
A
Provides nutrients to soil
13
Q
What plays role in creating soil
A
CLIMATE
vegetation
Time
14
Q
What is a soil profile
A
A section of soil extending from the surface to the bedrock
15
Q
What are the different layers called in a soil profile
A
Horizon
16
Q
What are the horizons
A
O horizon (organic matter, plant litter, animals, humus) A horizon (topsoil, humus, organisms) B horizon (subsoil, where rainwater percolates) C horizon (large clumps or partially weathered roock) R horizon (bedrock, undisturbed parent rock)
17
Q
Which horizon do organism live
A
A
18
Q
6 characteristics of soil
A
Colour Texture Structure Humus content Ph value Water content
19
Q
What might affect colour of soil
A
Rock it developed from
Processes that have occurred eg Leaching
20
Q
What gives soils their darker colour
A
Humus
21
Q
Why might soils be grey
A
Washed out by rain, lacking nutrients
22
Q
Soil structure refers to soil …
A
Peds
23
Q
Good soil structure allows movement of …
A
Water and air
24
Q
3 Ped types
A
Crumb
Blocky
Platy
25
Describe crumb soil
Small rounded grains
Near surface
Excellent for water movement
26
Example of crumb soil
Loam soil
27
Describe blocky soil
Cube shaped particles that fit tightly together
| Few pores
28
Example of blocky soil
Sandy soils
29
Describe platy soils
Thin flat plates that overlap
Compact
Hold up water movemeg
30
Example of platy soils
Clays
31
Texture of soil is determined by amount of
Sand
Silt
Clay
32
Texture of clay soils
Wet and waterlogged in winter
Dry and cracked in summer
(Sticky and smooth)
33
Texture of silt soils
Powdery
| Stick together when wet but won’t hold shape when dry
34
Do clay soils get waterlogged
Yes
35
Do silty soils get waterlogged
No
36
Sandy soil texture
Gritty
| Don’t stick together when wet
37
Do Sandy soils get waterlogged
No free draining
38
Loam soil texture
Contains equal amounts of sand, silt and clay so feels crumbly and moist
39
How does humus affect soil
Adds nutrients
Binds soil tighter
increases ability to hold water
Give colour
40
What is ph of soil affected by
Rock it formed from eg alkaline soils from alkaline rock like limestone
41
Desired ph for most plants
6.5
| Slightly acidic
42
An extremely acidic soil
Peat, little living things
43
Neutral soils are ideal for
Bacteria
44
Why is water important to a plant
Enables plant to absorb nutrient through water
Ena ale survival of microorganisms responsible for humus formation
Reduces soil erosion by wind
45
8 processes affecting soil characteristics
```
Weathering
Humification
Leaching
Podzolisation
Gleying
Laterisation
Salinisation
Calcification
```
46
Types of weathering creating smaller pieces for mineral matter of soil
```
Freeze thaw
Exfoliation
Carbonation
Hydrolysis
Oxidation
```
47
Does physical weathering change mineral make up
No
| Chemical does
48
Soil formed from carbonation
Dark brown alkaline soil rich in calcium
49
Hydrolysis forms what soil
Feldspar in rock changes to clay
50
Oxidation causes what soil
Reddish brown
51
What is humification
Method by which dead organic matter is converted into hummus by the action of fungi and bacteria
52
Humification occurs best in
Humid hot conditions
53
What is leaching
Removal of nutrients from soil by water.
Rainwater washes soluble substances through soil. It builds up in a layer in the soil
54
Where is leaching most common
Slopes
| Areas with heavy rainfall eg mountains -relief rain
55
What is poszolisation
An extreme type of leaching that occurs when rainwater is acidic
56
How does rainwater build up acidity for podzolisation
As coniferous forests die and decompose, they add acidity to the rainwater
57
What mineral does acidic rainwater not dissolve
Quartz
58
Colour of top layer of podzol
Ash Grey
59
What is gleying
When soils become waterlogged and lacks oxygen
60
Is there much living things in gley soils
Can’t grow in wet conditions
| Little oxygen
61
Colour of gley soils and why
Slightly blue/grey due to lack of oxygen
62
What is laterisation
Severe chemical weathering
All minerals are dissolved out of the soil except iron and aluminium oxides
Giving red colour
63
What is salinisation
The accumulation of mineral salts close to the surface of soil
64
Where does salinisation occur
Hot desert regions
Precipitation is low and evaporation is high
Groundwater is high in salt and as it evaporates salt is left
65
What is calcification
Calcium carbonate is concentrated near the surface of soil (horizon A)
66
Zonal soil in Ireland
Brown earth soil
67
Intrazonal soils in Ireland
Gley
| Peaty
68
Describe soil profile of brown earth soils
No distinct horizons as living things have mixed the soil up
69
Factors influencing BES in Ireland
```
Climate
Relief
Living organisms and vegetation
Parent material
Time
```
70
How does Irish climate influence brown earth soil
Temp; 15°c in July and 6°c in January. Good for keeping microorganisms alive year round
Rain; 1500mm year round
Long growing season
71
How does relief affect BES in Ireland
Temp; higher ground is colder than lowlands because temps decrease by 1° for every 100m climb, less animal activity and less humification
South facing slopes warmer than north.
72
Living organism and vegetation on BES
Deciduous forest (oak, ash, chestnut, bitch) provide plant litter for humification
Fungi and bacteria
Badgers, rabbits, foxes and hedgehogs churn soil
73
Parent material of most brown earth soils
Boulder clay deposited in last ice age
74
Parent material of acidic BES
Granite, schist or sandstone
75
Parent material of shallow BES (rendzina soil)
Limestone
76
Parent material of podzolised BES
In lowlands where glaciers deposited their load
77
How long ago did Irish BES soil
10,000 years ago in last ice age
78
Irish BES colour
Brown
Presence of humus makes darker
Leaching washes out nutrients making lighter
79
Ph of BES
Slightly alkaline due to temp and parent material
| Livy g things strive in thus pH
80
Is BES rich in humus
Yes
| Trees loose their leaves each autumn adding to amount of litter available for humification
81
Structure of Irish BES
Crumb
82
Use of Irish BES
Tillage
| Pasture
83
Texture of Irish Bes
Loam
84
Water content of BES
Depends on local conditions
Not too wet not too dry
Water content encourages plant growth
85
Is leaching common in Irish BES
It’s moderate
It washes nutrients into soil
Badly drained areas cause gley soils as BES is leached
86
natural causes of soil erosion
Rain
| Wind
87
How does rain cause soil erosion
Force and impact of rain breaks soil grains
Soil becomes saturated
Water starts to float on top
Rainwater carries away soil
88
How does wind cause soil erosion
Blowing dry and exposed soil away
89
3 types of wind movement
Saltation - medium particles carried short distances
Suspension - fine particles carried long distances
Surface creep - large particles move along surface
90
Human causes of soil erosion
Farming (over grazing, over cropping)
Deforestation
Tourism in mountain areas
Quad biking
91
Characteristic and composition of brown earth soil essay 3 aspects
Texture and structure
Humus content and colour
pH
92
What is desertification
The reas of desert into new lands, Turing productive land into wasteland
93
What is overgrazing
Overgrazing occurs when farmers let their animals feed on all the vegetation in the area, removing the protective layer of vegetation and leaving soil exposed
94
What is overcropping
When land is used for vegetation over and over and is not left to recover
95
What is monoculture
The same crop is planted in the same field year after year
96
What is a fallow year
A year to recover fro, growing
97
What is deforestation
The large scale clearing of forests and using the land for non forest purposes
98
Where is the Sahel
4000km east to west Africa including niger, Mali, Chad, Sudan and Ethiopia
99
Sabel population change pattern
Doubles every 20 years
100
Desert conditions advancing into Sahel at rate of
5-10km a year
101
In Chad how many people are food insecure
3.5 million
102
Example of crop monocultured in Africa
Cotton
103
Ways humans positively interact with soil imnsahel
The great green wall —- agroforestry
Low tech/low cost soil conservation:
Stone bunds
Zai holes
104
How wide was great green wall
15km
105
Why did great green wall fail
Little effort to involve local farmers in planting or maintaining
Exotic species planted
Not enough funding
106
What is agroforestry
Growing trees but also using the land to grow crops and/or rear animals
107
Why did agroforestry succeed
Native species used
Trees producing food were used
Trees increased soil fertility and reduce soil erosion
More funding (from global climate summit)
108
What are stone bunds
Bunds are a method of soil conservation where small stones are placed across the land to trap rainfall and encourage it to seep into the soil
109
What are zai holes
Holes that catch rainfall to stop if running off
110
Soil is too alkaline, how do I make it acidic
Crushed lime
111
An example of how weathering effects ph of soil
Carbonation
Making it more alkaline
Eg rendzina soils
112
Sandstone produces soil of what a)colour and b)ph
Pale
| Acidic
113
Limestone as a parent material produces soil of what a)colour and b)ph
Dark
| Alkaline (calcium carbonate)
