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EM > Agriculture and the Environment > Flashcards

Agriculture and the Environment Flashcards

1
Q

Define soil

A

Outer, loose layer that is found just below the surface of the earth

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2
Q

Soil Composition

A
  1. Inorganic material particles- 45%
  2. Organic matter- 5%
  3. Water- 25%
  4. Air- 25%
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3
Q

Characteristics of Clay

A

Less than 0.002 mm

Holds a high proportion of water due to the capillary attraction of the tiny spaces between its small particles- called a ‘heavy’ soil

Drains slowly

Takes longer to warm up in spring

Becomes hard and cracks during summer or dry periods

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4
Q

Characteristics of Silt

A

0.002-0.05 mm

Well drained

Hold more moisture than sandy soils

Easily compacted when wet

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5
Q

Characteristics of Sand

A

0.05-2 mm

Water drains through it easily- ‘light soil’

Warms up quicker than clay

Dries out quickly

Becomes acidic and infertile as plant nutrients are washed out by rain (leaching)

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6
Q

What is loam-based soil ?

A

Ideal medium- well-drained, fertile, and easily cultivated because its a mixture of clay, silt & sand

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7
Q

Importance of organic matter-

A

Reservoir of nutrients which are released into soil & absorbed by plants

Improves water holding capacity- helps prevent waterlogging & dehydration

binds/ clumps soil into aggregates that improve soil structure allowing it to take up and hold water better

Prevents soil erosion- stabilizes the soil & promotes stronger plant growth

Increased water infiltration- prevents soil from drying out & wind erosion

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8
Q

Define Subsistence farming :

A

Self-sufficiency farming in which farmers concentrate on growing or rearing enough food to feed themselves and their families with perhaps a little surplus generated occasionally (eg. Asia, Africa)

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9
Q

Define Commercial farming :

A

farming for a profit- growing crops or rearing animals to sell at market (e.g. MEDCS)

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10
Q

Define Arable farming

A

production of food, fodder and industrial crops

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11
Q

Define Slash and burn method

A

Type of subsistance

Clear felling & burning forests to create fields for crops & graze cattle- ash provides a fertility boost

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12
Q

Define Pastoral farming

A

Rearing animals for meat/ animal products (eg wool)

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13
Q

Define Intensive farming

A

Large investments of capital & technology to achieve high yields or output

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14
Q

Define Extensive farming

A

Not using external methods- letting it grow naturally

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15
Q

Define Irrigation

A

Artifically diverting water to farming areas to grow crops and sustain livestock

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16
Q

Where do the components of soil come from?

A
  1. Inorganic material particles- weathering & erosion of rocks
  2. Organic matter- from plants, animals, microorganisms and humus
  3. Water- precipitation (rain/snow) that drains into the soil
  4. Air- carbon dioxide > oxygen
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17
Q

Define humus

A

Decaying reamins of plants, animals and microorganisms

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18
Q

Most important minerals required by soil & why?

A
  1. Nitrogen- combines with glucose to form amino acids- create proteins for cell growth
  2. Phosphorous- required for respiration and growth & imp for DNA and cell membranes
  3. Potassium- for enzymes required for photosynthesis and respiration to function
  4. Magnesium- manufacturing chlorophyll needed for photosynthesis
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19
Q

Natural sources of plant nutrients

A
  1. Mineral ions (Nitratres, phosphates etc.)
  2. Organic Material
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20
Q

Define organic material

A

Remains of a plant or animal that was once alive and which has returned to the soil and been decomposed into humus by bacterial microorganisms

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21
Q

Define permeability

A

Ease with which water is able to infiltrate or move through the soil

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22
Q

What soil’s pH mean:

A

Below 7 (acidic)- nutrients won’t dissolve easily & won’t be able to go up the roots

6-7.5 (neutral)- nutrients will dissolve perfectly

Above 7 (alkaline)- nutrients won’t dissolve easily & won’t be able to go up the roots

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23
Q

Why would soil become more acidic over time?

A
  1. Rainfall weathers, washes and leaches certain minerals
  2. Decomposition of organic matter naturally adds acid
  3. Acid rain
  4. Use of chemical- based fertilisers on farms
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24
Q

Define agriculture

A

Agriculture or farming is the cultivation of the soil for the growing of crops and the rearing of animals

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25
Q

Intensive farming techniques to increase agricultural yield

A
  1. Rotation
  2. Fertilisers
  3. Irrigation
  4. Controlling pests and diseases
  5. Mechanisation
  6. Selective breeding
  7. Genetic modification/engineering
  8. Controlling growing environments
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26
Q

Explain crop rotation

A

Regularly changing the crop that grows in a particular place on a farm according to an agreed sequence

Growing the same crop in the same field continuously depletes the soil of the range of nutrients a plant requires to yield well

Therefore, with this method that crop will be replaced with a crop that draws other nutrients or returns the depleted nutrient through ‘nitrogen fixing’

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27
Q

Explain nitrogen fixing

A

(Symbiotic relationship)

Plants such as clovers, peas, beans are ‘legume’ plants that contain a special nodule that holds bacteria which feeds by extracting nitrogen from the atmosphere to produce nitrate chemical compounds

28
Q

Benefits of crop rotation

A
  1. Maintains soil fertility
  2. Improves crop yields
  3. Controls bacteria, fungus, parasite build-up
29
Q

Define fertiliser

A

Any natural or synthetic substance that is added to soils to supply one or more nutrients removed by growing crops

30
Q

Explain decompostition

A

The nutrient ions decompose into the soil as plants die by bacteria
They break down organic molecules and release nutrients back into the soil

31
Q

Benefits of fertilisers

A
  1. Replace lost nutrients
  2. Maintain the productivity of the land through constantly providing optimum conditions for plant growth
32
Q

How can you replace lost soil fertility sustainably?

A
  1. Rotation
  2. Nitrogen fixing legumes
  3. Composted waste produced
  4. Natural animal manures
33
Q

Disadvantages of using fertilizers

A
  1. Eutrophication
  2. Soil acidification
  3. Contributes to greenhouse gas emissions (using nitrogen fertilizers release nitrous oxide)
34
Q

Define eutrophication

A

It occurs when fertilisers are washed off the land by rainwater into rivers and lakes
High concentration of nitrates and phosphates build up which causes rapid algae growth, ‘blooms’
These cover the water surface which prevents light and oxygen from reaching the aquatic life
Once dead, bacteria breaks it down which leaves the waterbody devoid of life

35
Q

Types of irrigation

A
  1. Surface irrigation
  2. Localised irrigation
  3. Sprinkler irrigation
  4. Sub/seepage irrigation
  5. In-ground irrigation
36
Q

Define surface irrigation

A

Covering/ flooding entire cultivated area with water

37
Q

Define localised irrigation

A

Small drops to the roots through a network of narrow rubber pipes

38
Q

Define sprinkler irrigation

A

Imitates rainfall
Water piped then sprayed

39
Q

Define sub/seepage irrigation

A

Provides roots with water from beneath the soil

40
Q

Define in-ground irrigation

A

Entire irrigation system burried underground

41
Q

Types of pesticides

A
  1. Fungicides
  2. Herbicides
  3. Insecticides
42
Q

Difference between the 3 pesticides

A

Fungicides kill fungi that attack plants

Herbicides are used against weeds which absorb toxins through their roots and leaves

Insecticides kill insects that attack crop plants

43
Q

Disadvantages of pesticides

A
  1. They destroy the target and also harmless, potentially useful non-pest species
    - This destroys the food chain
  2. Bio accumulation
    - Populations of apex predators especially will decline
  3. Overuse will lead to insects & weeds becoming resistant or immune
44
Q

Define bioaccumalation

A

The gradual build-up of pesticide-spread toxins in organisms in increasing amounts up the food chain

45
Q

Alternatives to synthentic chemical based methods of controlling pests

A
  1. Encouraging their natural predators to attack them
  2. Rotation won’t allow them to build up
  3. Mixed cultures > Monocultures making it harder for pests to locate their main crop
  4. Labour intensive methods (picking insects by hand)
  5. Naturally made pesticides- made from dried flowers
46
Q

Benefits of mechanisation

A
  1. Cheaper- individually treating plants according to what they need
  2. Faster/ more efficient- no human error/holidays
  3. Enabled land that was previously impossible to farm to be brought into cultivation
47
Q

Ecxplain selective breeding

A

Increases yields by only breeding from the best animals/ plants.

Pastoral- breeding from the most efficient animal, genes passed in offspring, farmer left with many efficient animals

Arable- cross breed a highly efficient plant with a highly resistant to disease plant to create the best plant

48
Q

Explain genetic modification

A

Artifically changing the genetic structure of the cells of farm crops or animals by swapping genes within and across species to improve yields

Selective breeding in a laboratory

49
Q

Benefits of a controlled growing environment

A
  1. Farmer has complete control
  2. Farmer’s costs reduced and profits increased due to shortened growing season
  3. Extra CO2 pumped–> more photosynthesis
  4. Less pesticides used (hydroponics)
50
Q

Impact of agriculture

A
  1. Overproduction and waste
  2. Cash crops replacing food crops in LEDCS
51
Q

Reasons for overproduction in MEDCs

A
  1. Farmers recieve a minimum wage type subsidy for producing food. If they produce excess the government will buy the surplus
  2. Market is saturated already
  3. Low quality, pests, disease, weather– > can’t be harvested
52
Q

Reasons for wastage by consumers in MEDCs

A
  1. Supermarket conditions ‘buy 1 get 1 free’
  2. Poor packaging and consumer knowledge
    (labels confusion & not sure how to store)
53
Q

Benefits for LEDCs producing cash crops they can export to MEDCs for profits

A
  1. Have cash to buy food locally
  2. Employ relatives
  3. Pay for family expenses
54
Q

Disadvantages of planting cash crops from LEDCS

A
  1. Farmers don’t get to set their prices
  2. Very vulnerable to change in demand
  3. If cash income drops, farmers will face malnutrition or be forced to move
  4. Small land not viable for cash crops, they’ll have to sell to larger estates
  5. Cash crops require more water (deplete water supplies) & nutrients in soil won’t be replenished
55
Q

Causes of soil erosion

A
  1. Overcultivation
  2. Overgrazing
56
Q

Explain overcultivation

A

Continous and excessive use of farmland for crops to a point where soils are depleted of nutrients and the soil structure is severely broken down by a lack of organic matter

57
Q

Explain overgrazing

A

It degrades the land by stripping away it’s vegetation cover as a result of the density of livestock being greater than the carrying capacity of the soil

58
Q

What is land degradation

A

Removing the protective cover of vegetation and its roots and allowing the soil structure to disintegrate to a point where the land no longer has an economic or ecological value

59
Q

Impacts of soil erosion

A
  1. Removes essential nutrients from the land
  2. Desertification–> Displacement of people
  3. Habitat loss
  4. Silting up of rivers
  5. Sedimentation which damages the barrier reef
60
Q

Define leaching

A

Soaking away of soluble nutrients because, as a result of overcultivation or grazing, there are too few plant roots in the soil to absorb the nutrients and lock them away in plant tissue

61
Q

How can you manage soil erosion?

A
  1. Conserve/ Plant vegetation cover- root systems anchor the soil

Eg. Wind breaks: Lines of trees planted to face the prevailing wind and filter out 50-60% of its strength

  1. Cropping systems and ploughing techniques

Intercropping rather than monocropping has more fertile soil
Contour ploughing allows rainwater more time to soak into the soil and prevent rapid run-off

62
Q

Define intercropping

A

Growing 2 or more crops in the same field or area

63
Q

Cropping systems

A

Intercropping (E.g Mixed cropping)
Monocropping
Row/Strip cropping

64
Q

Define sustainable agriculture

A

Farming that seeks to balance profitable yields of crops and livestock with protecting and conserving the ecosystems upon which all life depends, ensuring the fair and ethical working conditions and remuneration of workers and safeguarding the health and welfare of consumers and all farmed species

65
Q

How can you farm sustainably?

A
  1. Pay workers minimum wage
  2. Crop rotation (soil fertility maintained)
  3. Rotational grazing
  4. Avoid synthetic fertilizers
66
Q

How do you protect water in the environment?

A
  1. Targeted drip irrigation systems
  2. Low pressure sprinkler systems
  3. Harvest rainwater run-off from roofs
  4. Technology can be used to detect how much water is actually needed

EM (10 decks)

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