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ENVS > Chapter 2 > Flashcards

Chapter 2 Flashcards

1
Q

What do crops require?

A

Water
Sun
CO2

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2
Q

Define soil.

A

(i) The unconsolidated mineral or organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants

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3
Q

How many soil orders are there?

A

10 different soil orders

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4
Q

Why are soils important?

A
  • Medium for plant growth
  • Part of hydrologic cycle (water supply and purification)
  • Part of nutrition cycle (capture, soil and supply nutrients)
  • Habitat for soil organisms
  • Also an engineering medium
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5
Q

What are the components of soil?

A
  • Air(25%)
  • Water (25%)
  • Organic Matter (5%)
  • Mineral Particles (45%)
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6
Q

Define Porosity

A

Amount of open space between soil particles

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7
Q

What are the primary particles of soil?

A
  • Gravel (2mm to 75mm)
  • Sand (0.05mm to 2mm)
  • Silt (0.002mm to 0.05mm)
  • Clay(<0.002mm)
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8
Q

What is the most important fraction of soil and why?

A

Clay

  • vary large surface area
  • surfaces are negatively charges (ability to store and release some nutrients)
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9
Q

What is soil structure?

A

The arrangement of primary particles into secondary particles (aggregates or peds)

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10
Q

What are binding agents of soil?

A
  • Roots and fungal hyphae
  • Organic material
  • Clays
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11
Q

What are the benefits of soil texture and structure?

A
  • Water holding capacity/drainage
  • Susceptibility to erosion
  • Fertility (ability to store plant nutrients)
  • Pollutant movement and leaching
  • Compactability
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12
Q

How many trophic levels are there?

A

5 and higher

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13
Q

What is in the first trophic level?

A

Photosynthesis

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14
Q

What is in the second trophic level?

A

Decomposers
Pathogens
Parasites
Root feeders(nematodes)

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15
Q

What is in the third trophic level?

A

Predators (protozoa)

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16
Q

What is in the fourth and fifth trophic level?

A

Higher level predators

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17
Q

What are beneficial effects of soil organisms?

A
  • Decomposition of organic material (nutrient cycling and carbon cycling)
  • Plant protection
  • Aeration
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18
Q

What is soil organic matter?

A
  • Biologically derived organic material
  • Unaltered materials (forest litter layers)
  • Altered decomposed materials (soil humus)
  • The dead stuff
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19
Q

Define Heterogeneous

A

Material at different stages of decomposition

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20
Q

What is the biological importance of SOM?

A

Source of energy for plants and animals

Source of nutrients for plants and animals

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21
Q

What is the physical importance of SOM?

A 
Stability of soil (stable structure)(Water retention)
Soil colour (affects soil temperature)
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22
Q

What is the chemical importance of SOM?

A

Nutrient cycling

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23
Q

What percentage of organic soils, is organic matter?

A

30%

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24
Q

When can organic soils be productive?

A

When properly drained and managed

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25
Q

Soil Air is low in ____ and high in ____

A

Low in oxygen

High in Carbon dioxide

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26
Q

Define aerobic soil

A

Soil that is high in oxygen

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27
Q

Define anaerobic soil

A

Soil that is low in oxygen

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28
Q

Anaerobic and aerobic environments can affect?

A

Plant growth
Nutrient content
Greenhouse gas emissions

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29
Q

What is the importance of soil water?

A

Serves as a carrier of nutrients
Regulates soil temperature
Soil forming process depends on water

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30
Q

How much water goes to agriculture?

A

58%

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31
Q

Define tillage

A

Preparation of soil often with mechanized equipment

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32
Q

What is used for primary tillage?

A

Ploughs

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33
Q

What is used for secondary tillage?

A

Harrows and cultivators

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34
Q

Benefits of Tillage

A

Soil loosening and aeration
Organic material and nutrient mixing
Mechanical weed destruction

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35
Q

What are disadvantages of tillage

A 
More exposed soil surface
Increases organic matter decomposition 
Decreased organisms
Fuel consumption/greenhouse gas emissions 
Soil compaction
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36
Q

Which type of tillage leaves the most plant residue?

A

Conservation tillage

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37
Q

What types of tillage are used for conservation tillage?

A

Chisel plough
Strip till
No till

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38
Q

What are benefits of conservation tillage?

A

Reduced soil erosion
Increased organic matter
Reduced evaporation
Reduced energy consumption

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39
Q

What are the costs of conservation tillage?

A

Specialized equipment needed
Colder and wetter soils
Increased herbicide use

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40
Q

What are some macronutrients?

A

C, H, O,N, P, K, Ca, Mg, S

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41
Q

How are macro nutrients measured?

A

PPM parts per million

1 PPM = 1 1/4 two litre bottle

42
Q

What are some micro nutrients?

A

Fe, Mn, Mo, B, Cu, Zn, Cl, Co, Ni

43
Q

How are micro nutrients measured?

A

PPB parts per billion

1 PPB = 1/2 teaspoon

44
Q

What might lead to nutrient deficiencies?

A

Leached, sandy soil
Intensive cropping
Eroded soils
Soils with low organic matter

45
Q

What pH levels are most soils?

A

6 - 7.5 pH (neutral)

46
Q

Define Eutrophication

A

Over fertilization with respect to nitrogen

47
Q

What does nitrogen add to soil?

A

Atmospheric deposition
Added organic matter
Inorganic fertilizer addition
Biological N fixation

48
Q

In relation to nitrogen what are some losses to the soil?

A

Very easily lost via leaching
Erosion and run off
Plant uptake
Gaseous losses

49
Q

What are the three biological nitrogen fixation systems?

A
  1. Symbiotic with plant, nodule-forming -
    Legumes (Rhizobia bacteria with soybeans)
  2. Symbiotic with plants, non-nodule-forming
    - Lichens = fungus + cyanobacteria or other bacteria
  3. Non-symbiotic – cyanobacteria
50
Q

What is the importance of phosphorus in the soil?

A

Energy transformations

Root development

51
Q

What does phosphorus add to the soil? Any losses?

A

Additions
Fertilizers
Added organic matter
Atmospheric decomposition

Losses
Erosion
Plant uptake and harvest

52
Q

What is the importance of potassium in the soil?

A

Important in synthesis of proteins, carbohydrates and chlorophyll; helps plants to adapt to environmental stresses

53
Q

What does potassium add to the soil? Any losses?

A

Additions
Added organic matter
Fertilizer addition
Atmospheric deposition

Losses
Run-off, leaching and erosion
Plant uptake and harvest

54
Q

What are some things in organic fertilizers?

A

Animal manure
Green manure
Bio solids (industrial waste)

55
Q

What are the benefits to inorganic fertilizers?

A

Can be applied more precise than with organic fertilizers

Higher % content

56
Q

When do you apply nitrogen?

A

Spring

57
Q

When do you apply P, K?

A

Fall or spring

58
Q

Types of methods to apply fertilizers

A

Banding prior to, or during, planting
Side - dressing after planting
Foliar application

59
Q

Where is there surplus water?

A

Areas with high precipitation
Low lying soils or high water tables
Slow draining soils

60
Q

Name the types of soil drainage systems

A 
Drainage ditches (follows land contours)
Land smoothing (prevents ponding in depressions)
Tile drainage - buried perforated pipes
61
Q

What are the benefits to soil drainage?

A

Improved workability and aeration
More rapid soil warming
Reduced fungal diseases
Decreased gas emissions

62
Q

What are some problems with soil drainage?

A

Loss of wildlife habitat
Loss of N
Loss of organic matter

63
Q

Where is there water deficits?

A

Areas with low precipitation and/or high evaporation

Excessively well drained soils

64
Q

How do you control loss of water?

A 
Control evapotranspiration - controlling weeds and fallow periods
Control evaporation (conservation tillage)
65
Q

What is the largest consumptive user of water in agriculture?

A

Irrigation

66
Q

Name the types of irrigation

A

Surface irrigation
Sprinkler irrigation
Micro - irrigation (drip or trickle - most efficient)

67
Q

What areas do not have access to good water?

A

Arid and semi - arid areas

68
Q

What is a pest?

A

Any organism that has a negative effect on human health or economics

69
Q

Name 3 methods to control pest

A 
Chemical control (pesticides)
Cultural control
Physical/mechanical control 
Biological control
Genetic control
Natural chemical control
70
Q

Benefits of pesticides

A

Protects crops
Protects health ( malaria)
Convenience/Aesthetics

71
Q

What are the 4 ways pesticides are grouped?

A

Pests they control
Chemical structure
How/when they work
Mode of action

72
Q

What does postemergent mean?

A

A weed emerges after seeding

73
Q

What does PCPA stand for?

A

Pest control products act

74
Q

What does PCPA do?

A

Pesticide registration and re-evaluation
Human health and safety
Environmental impact
Compliance and enforcement

75
Q

Name 3 commonly used pesticides in Ontario

A 
Glyphosate
Atrazine
Diazinon
Chlorothalonil
Neonicotinoids
76
Q

What does IPM stand for?

A

Integrated pest management

77
Q

What is IPM?

A

Environmentally sensitive approach to pest control

78
Q

What is at the top of the IPM pyramid?

A

Chemical (pesticide)

79
Q

Soil structure describes the proportion of sand, silt and clay particles present in the soil while soil texture refers to the arrangement of these soil particles into aggregates.

A

False

80
Q

Top soil is the most productive soil layer because:

A

It is where most organic matter is found

81
Q

The process by which organisms can take nitrogen from the atmosphere and convert it to soil nitrogen.

A

Biological Nitrogen Fixation

82
Q

The macronutrient that is difficult to manage because it is very strongly held by most soils is:

A

Phosphorous

83
Q

In conservation tillage operations at least _____ of the soil surface is covered with plant residues.

A

30%

84
Q

We generally do NOT find nutrient deficiencies associated with the following soil condition:

A

Soils with high organic matter contents

85
Q

The Haber-Bosch process is the industrial process used to produce:

A

Nitrogen fertilizers

86
Q

The first trophic level of a soil food web consists of:

A

Plants

87
Q

Which of the following statements about soil organic matter is NOT true:

a) Soil organic matter is biologically derived
b) Soil organic matter usually constitutes between 1 and 5% of a mineral soil
c) Soil organic matter is a very homogeneous mixture of materials
d) Soil organic matter constitutes approximately 30% of an organic soil
e) Soil organic matter is very important for soil structural stability

A

C - Soil organic matter is a very homogeneous mixture of materials

88
Q

Nitrification describes the process whereby:

A

Ammonium is converted into nitrate (the more plant available form of nitrogen)

89
Q

The following is a broad spectrum herbicide used to kill broad-leaf weeds and grasses:

A

Glyphosate

90
Q

The following is the commonly used insecticide linked to Honey Bee Colony Collapse Disorder:

A

Neonicotinoids

91
Q

Systemic pesticides are pesticides that kill as a result of direct contact.

A

False

92
Q

The environmentally sensitive approach to pest control that uses pesticides judiciously is called:

A

IPM

93
Q

A soil with greater than 30% organic matter is considered to be an organic soil.

A

True

94
Q

Moldboard ploughs are generally associated with conservation tillage operations.

A

False

95
Q

An important benefit of conservation tillage is decreased weeds.

A

False

96
Q

No-till operations are particularly suitable for cereal crops.

A

True

97
Q

Soil phosphorous is particularly important for plant root development.

A

True

98
Q

Broadcasting is better than side-dressing because it involves the localized placement of fertilizers.

A

False

99
Q

Draining soils can lead to increased fungal diseases in the soil.

A

False

100
Q

Irrigated agriculture is the largest consumer of freshwater in the world.

A

True

101
Q

In order to improve the water use efficiency of irrigation the following can be used:

A

Drip irrigation

ENVS (9 decks)

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