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Environmental Science > Lecture 16/17 > Flashcards

Lecture 16/17 Flashcards

1
Q

Why is soil considered an ecosystem

A

it contains both living and non-living matter

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2
Q

What are the most important areas for agriculture were originally grass lands

A
  • Northern mixed grass prairie (North America)
  • Tall grass prairie (North America)
  • Pampas (South America)
  • Steppes (Europe/ Asia)
  • Savannah (Africa)
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3
Q

What are the factors that influence soil formation

A
  • organisms
  • topography
  • time
  • climate
  • parent material
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4
Q

What are the types of weathering processes

A
  • physical (wind, rain, thermal expansion/contraction, water freezing)
  • chemical (water and gases)
  • biological (tree roots and lichens)
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5
Q

define humus

A

dark, spongy, crumbly mass of organic material formed by partial decomposition

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6
Q

What are soil layers described by

A
  • colour, texture, structure, pH
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7
Q

What are the different soil layers

A

O horizon = surface litter
A horizon = topsoil –> contains decaying organic matter (humus) and living soil organisms
B horizon = subsoil –> denser than A horizon, higher mineral content, lower fertility
C horizon = contains rock in the process of being broken (weathering) to produce new soil
R horizon = solid rock that has not been broken down

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8
Q

define ion exchange capacity

A
  • cations (K, Na, Ca, Mg) remain in root zone
  • anions (NO3, PO4, SO4) leach out of root zone
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9
Q

define agriculture

A

The practice of growing crops and raising livestock for human use and consumption

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10
Q

define cropland

A

land used to grow crop plants

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11
Q

define rangeland or pasture

A

land used for grazing livestock

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12
Q

define subsistence agriculture (traditional agriculture)

A

families produce only enough food for themselves
- supplemented by hunting

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13
Q

define intensive agriculture (traditional agriculture)

A

produces excess food to sell
- uses animals, irrigation, and natural fertilizers
- does not use fossil fuels

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14
Q

define monoculture

A

uniform planting of one single crop
- not natural

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15
Q

what are some uses of monoculture

A
  1. large-scale mechanization (machinery)
  2. high fossil fuel quantities to boost yields
  3. irrigation (high water needs)
  4. chemicals (pesticides and fertilizers)
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16
Q

define feedlots (factory farms)

A

CAFO (concentrated animal feeding operations)
- Large warehouses or pens designed to deliver energy-rich food to animals living in extremely high density enclosures (pens, cages)

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17
Q

What are some benefits of CAFO’s

A
  • greater production of food
  • unavoidable in countries with high levels of meat consumption,
  • reduces demand for land for pasture
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18
Q

What are some drawbacks to CAFO’s

A
  • contributions to water/air pollution
  • poor waste containment causes outbreaks of disease/infections
  • high use of antibiotics to control disease – antibiotic resistance
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19
Q

define extensification

A

bringing more land into production

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20
Q

define intensification

A

better productivity per unit of land

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21
Q

what is the green revolution dependent on

A
  • synthetic fertilizers
  • chemical pesticides
  • irrigation
  • heavy equipment
22
Q

what are some positive effects of the green revolution

A
  • prevented some deforestation
  • preserved biodiversity
23
Q

what are some negative effects of the green revolution

A
  • pests
  • pollution (fertilizers)
  • erosion
  • salinization
  • desertification
24
Q

define pest

A

any organism that damages valuable crops and/or livestock

25
Q

define weed

A

any plant that competes with crops

26
Q

define pesticides

A

poisons that target pest organisms

27
Q

define insecticides

A

target insects

28
Q

define herbicides

A

target plants

29
Q

fungicides

A

target fungi

30
Q

define evolutionary arms race

A

chemists increase chemical toxicity to compete with resistant pests

31
Q

define pollination

A

male sex cells (pollen) fertilize female sex cells
- by wind, water, or animals

32
Q

What are some examples of animal pollinators

A
  • hummingbirds and other birds
  • bats
  • insects (bees, butterflies, flies, moths)
33
Q

define soil degradation

A

damage/loss of soils from poor management
- productive soils are renewable

34
Q

what are the two reasons for erosion

A
  • due to drought
  • due to mismanagement of soils
35
Q

define swidden agriculture

A
  • cultivation of a plot for a few years and then abandoning it and moving on to a new plot of land (that is burned and cleared for agriculture)
36
Q

define desertification

A

when there is a loss of more than 10% productivity of crops

37
Q

what causes desertification

A
  • erosion, soil compaction, forest removal, overgrazing, salinization, climate change, depletion of water sources
38
Q

what are some solutions for erosion and desertification

A

conserve soils, restore/maintain plant cover, prevent salinization, improve fertilization practices, reduce overgazing

39
Q

define crop rotation

A

alternating crops from year to year

40
Q

define contour farming

A

plowing fields perpendicular to the slope

41
Q

define terracing

A

level platforms are cut into steep hillsides

42
Q

define intercropping

A

planting different types of crops in alternating bands or other arrangements
- more natural

43
Q

define reduced tillage

A

furrows are cut into the soil, a seed is dropped in and furrow is closed
- no-till farming disturbs soil even less

44
Q

define plant cover

A
  • reduces soil erosion along creeks and roadsides
  • stabilize soils by using plants to anchor soil
  • use tree-planting programs to slow erosion
45
Q

define irrigation (prevent salinization problems)

A

artificially providing water to support agriculture

46
Q

define waterlogging (prevent salinization problems)

A

over-irrigated soils - water suffocates roots

47
Q

define salinization (prevent salinization problems)

A

buildup of salts in surface soil layers

48
Q

what are easier and cheaper ways to prevent salinization

A
  • do not plant water-guzzling crops in sensitive areas
  • choose appropriate crops for area
  • irrigate with low-salt water
49
Q

define fertilizer

A

substances that contain essential nutrients

50
Q

define inorganic fertilizers

A

mined or synthetically manufactured mineral supplements

51
Q

define organic fertilizers

A

remains or wastes of organisms
- manure, crop residues, fresh vegetation
- compost= produced when decomposers break down organic matter

52
Q
A

Environmental Science (9 decks)

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