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ESS > unit 5 > Flashcards

unit 5 Flashcards

1
Q

what is soil?

A
  • complex ecosystem
  • made up of minerals, organic material, gases and liquids which forms the habitat for many animals and plants
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2
Q

facts about soil!!!

A
  • all food we consume depends on soil
  • soil is a habitat for many organisms
  • as well as holding water and mineral nutrients that plants depend upon, soils act as a massive filter for any water that passes through it, often altering the chemistry of that water
  • soils store and transfer heat so affecting atmospheric temperature which in turn can affect the interactions between soil and atmospheric moisture
  • soils are part of the lithosphere where life processes and soil forming processes take place
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3
Q

storages

A

organic matter, organisms, nutrients, minerals, air and water

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4
Q

transfers within the soil

A

biological mixing, translocation (moving of soil particles in suspension) and leaching (minerals dissolved in water moved through soil)

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5
Q

inputs

A

organic material including leaf litter and inorganic matter from parent material, precipitation and energy

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6
Q

outputs

A

uptake by plants and soil erosion

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7
Q

transformations

A

decomposition, weathering and nutrient cycling

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8
Q

four main components that make up soil

A
  • mineral particles mainly from the underlying rock
  • organic remains that have come from plants and animals
  • water within spaces between soil grains
  • air also within the soil grains
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9
Q

horizons

A

processes such as downward and upward movement of minerals leads to soil being processed in distinct horizons (levels)

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10
Q

top layer vs lower layers

A

top layer often rich in organic material whilst lower layer consists of inorganic material

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11
Q

translocation

A

materials are sorted and layers are formed by carrying water particles either up or down

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12
Q

types of horizons

A

O horizon, A horizon, B horizon, C horizon, R horizon

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13
Q

O horizons

A

uppermost layer; has newly added organic material

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14
Q

A horizon

A

humus builds up - humus layer = “good stuff” and forms via inorganic matter mixed with organic matter

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15
Q

B horizon

A

soluble minerals and organic matter tend to be deposited from the layer above

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16
Q

C horizon

A

mainly weathered rock from which soils forms

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17
Q

R horizon

A

parent material (bedrock)

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18
Q

types of soil texture

A
  1. Sandy: Gritty and fall apart easily
  2. Silty: Slippery and wet; hold together better than sandy soil
  3. Clay: sticky and can be rolled into a ball easily
  4. Loam soil: ideal for agriculture
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19
Q

porosity

A

amount of space between particles

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20
Q

permeability

A

the ease at which gases and liquids pass through soil

21
Q

acidification of soil

A

acid rain causing pollution, adversely affecting soil and causing damage to evergreen forestry

22
Q

fertile soil =

A

non renewable resource

23
Q

main nutrients are

A

Nitrates, Phosphates and Potassium (NPK)
- N: For leaf and stem
- P: For root system
- K: Flower head/fruit

24
Q

types of farming systems

A
  1. Subsistence farming
  2. Commercial farming
  3. Extensive and Intensive
25
Q

subsistence farming

A
  • provision of food by farmers for their community or family
  • no surplus
  • low inputs of energy: they are unlikely to produce more than they need
26
Q

commercial farming

A
  • large, profit making scale
  • monoculture or of one type of animal
  • high levels of technology
27
Q

extensive and intensive farming

A

extensive: more use of land with lower density
intensive: uses intensive amount of land with higher input

28
Q

basic food facts

A
  • world food production is concentrated in the northern hemisphere temperate zone
  • Africa: only 7% of land area is cultivated
  • LEDCs have 80% of the world’s human population
29
Q

factors that influence choice of food eaten and grown

A
  • climate
  • cultural and religious
  • political
  • socio-economic
30
Q

history of farming and domestication

A
  • animal domestication: came before crop farming
  • livestock are useful means of converting plant material
31
Q

arable farming

A
  • seeds of crop plants deliberately sown into the soil
  • plants are monoculture –> they are grown into high density
32
Q

harvesting

A
  • requires the removal of biomass from the field
  • net loss of biomass, nutrients, minerals
33
Q

crop rotation

A
  • one way of addressing loss of soil fertility
  • leguminous crops (beans, peas, soya) add nitrogen to soil
34
Q

farming energy budget

A
  • energy contained within the crop of harvested product per unit area
  • efficiency: a system with inputs, outputs and storage
35
Q

example: rice production in Borneo and California

A

borneo: traditional, extensive rice production
- low inputs of chemical and energy
- high labour intensity
- low productivity
california: intensive
- high inputs of chemical and energy
- low labour intensity
- high productivity

36
Q

terrestrial vs aquatic food systems

A

terrestrial:
- usually harvested at first (crops) or second trophic level
- meat comes from primary consumers (pig, chicken)
aquatic:
- mostly from higher trophic levels
- less efficient than terrestrial because of lack of balance in consumption from trophic levels

37
Q

factors causing a decrease in agricultural land

A
  • soil erosion
  • salinisation
  • desertification
  • urbanisation
38
Q

how to increase sustainability of food supplies

A
  1. Maximizing yield:​ Improve technology, Alter what we grow or a new Green Revolution
  2. Reduce food waste:​ Improve storage
    - LEDC: waste mostly in production and storage (eg: no refrigeration, lack of good
    storage, severe weather)
    - MEDC: mostly in consumption → buying more than what’s needed, stricter standards in
    supermarket (round apples only)
  3. Monitoring and control:​ Regulate imports and exports to reduce unsustainable
    agricultural practices
  4. Change attitudes towards diet and food:​ eat less meat, eat different crops, increase
    insect consumption → more protein
  5. Reduce food processing:​ Decreases use of transport and packaging (ex: plastic, fuel,
    etc. - overall decrease in energy use)
39
Q

predictions

A
  • more people will eat meat
  • population growth - ?
  • decrease in hungry people to about 440m
  • extra billion tonnes of cereal will be needed
40
Q

2 types of processes (which give rise to soil degradation):

A
  1. Taking away soil (erosion): Occurs when there is no vegetation in the soil
  2. Making soil less suitable for use: - chemicals entering soil which render soil useless in the long run
    - human activities: overgrazing, deforestation, unsustainable agriculture
41
Q

overgrazing

A
  • when too many animals graze in the same area
  • leaves bare patches where roots don’t hold soil together
    **Sahel region: Africa –> occurs there (1970s-80s)
42
Q

overcropping

A
  • depletes soil nutrients and makes soil dry (hence risk of erosion)
  • reduced soil fertility
43
Q

deforestation: removal of forests

A
  • removal of vegetation leads to erosion –> through water as areas with forests are relatively wet
44
Q

unsustainable agriculture techniques

A
  • Total removal of crops after harvest
  • Plowing in direction of the slope → makes ready-made channels for rainwater to flow
    down
  • Excessive use of pesticide
  • Irrigation - can cause salinization as minerals dissolved in irrigation water remain in the
    top layer of the soil and form a hard salty crust making the land unsuitable for farming.
    Case study: Drip technology → Israel
  • Monocropping: nutrients are depleted and soil loses fertility
45
Q

urbanisation: refers to the increasing number of people that live in urban areas

A
  • more people live in urban regions than in rural for the first time in human history
  • a lot of potential agriculturally sustainable land is used for cities
46
Q

soil erosion: 3 major processes

A
  1. Sheet wash: surface soil washed away during storm periods/landslides
  2. Gullying: channels developing on hillsides after rainfall; become deeper over time
  3. Wind erosion: drier soils are removed from the surface from high winds
47
Q

soil conservation

A
  • insert soil conditioners
    a. chalk, crushed limestone
    b. counters soil acidification
    c. lime
  • wind reduction
    a. plant trees/bushes between fields or alternate low and high crops (strip cultivation); or build fences
  • soil conserving cultivation techniques
    a. terracing
    b. plowing
    c. contour farming
  • improve irrigation techniques
48
Q
A

ESS (8 decks)

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