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General soil Flashcards

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1
Q

What are 5 reasons we should examine soils?

A
  1. Food production (through crops)
  2. Provides a metric of biological diversity
  3. Carbon cycling
  4. Water quality
  5. Plant respiration/photosynthesis
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2
Q

What are the 6 main functions of soil?

A
  1. Water supply & purification
  2. Medium for plant growth
  3. Habitat for organisms
  4. Nutrient/waste recycling
  5. Engineering medium
  6. Atmospheric modifier
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3
Q

What are the 4 soil forming processes?

A
  1. Transformation
  2. Translocation
  3. Addition
  4. Loss
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4
Q

What are the 3 common soil physical properties?

A
  1. Density
  2. Texture
  3. Color
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5
Q

FITB: Soil textures can have different ____________ for sands, silt and clay

A

Thresholds

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6
Q

FITB: Sands are mainly composed of ______ grains

A

Quartz

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7
Q

How do sands feel?

A

Gritty

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8
Q

T/F: Sand grains are not visible to the naked eye

A

False; they are

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9
Q

Do sands have high or low surface areas?

A

Low

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10
Q

Why are plants unable to grow in sandy soils?

A

Because there are very few nutrients found within sands

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11
Q

T/F: Sand cannot store water

A

True

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12
Q

Does water move slowly or quickly through sand?

A

Quickly

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13
Q

FITB: Silts are composed of ____-sand particles

A

Micro

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14
Q

What does silt feel like?

A

Smooth, chalky, like flour

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15
Q

T/F: Silt is sticky when wet

A

False

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16
Q

T/F: Silt particles can be seen by the naked eye with no microscope needed

A

False; visible in field lens

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17
Q

T/F: Silt can hold more water than sand

A

True

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18
Q

Does silt have a higher or lower surface area?

A

Higher

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19
Q

What is a unique characteristic of silt?

A

It releases plant-available nutrients

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20
Q

What is the texture of clay like?

How does it appear to the eye?

A

Flat; plate-like

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21
Q

How is clay formed?

A

From weathering

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22
Q

What does clay feel like?

A

Sticky, plastic-like

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23
Q

T/F: Clay can be molded

A

True; think of art projects you did as a kid

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24
Q

FITB: When clay is dry, it can be described as a ____ mass

A

Hard

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25
Q

Does physical or chemical weathering occur with clay?

A

Chemical

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26
Q

T/F: Clay cannot shrink nor can it swell

A

False; it can do both of these things

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27
Q

Does clay have a high or low surface area?

A

Very high

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28
Q

Soil textural classes are made up of ______, ________, & _______

A
  1. Sand
  2. Silt
  3. Clay
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29
Q

T/F: Soil color does control the processes within the soil

A

False

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30
Q

TOT: Soil color can indicate that something has stayed the same/changed in the soil

A

Changed

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31
Q

Color wise, what colors make up a soil with silts & clays?

A

Brown, tan, yellow

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32
Q

How can you tell if there is a lack of other particles such as silt and clay?

A

If there is only sand left in the soil

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33
Q

T/F: The wetter the soil, the lighter it will be

A

False! It will definitely be darker in color

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34
Q

What does oxidation state mean?

A

The availability of oxygen within the soil

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35
Q

If you have oxidized iron, what color is going to appear?

A

Rust color (orange)

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36
Q

When iron is reduced, what color does it become?

A

Gray

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37
Q

Oxidized environments can be associated with well/poor drained environments?

A

Well-drained

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38
Q

T/F: Reduction is the opposite of oxidation

A

True

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39
Q

What is the Munsell Color System?

A

A book that contains a numerical system in which one can associate soil sample colors with (to compare)

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40
Q

Munsell colors are arranged according to 3 features; which are these 3 features? (in order)

A
  1. Hue - how red/yellow (10YR)
  2. Value - Light or dark (8-light, 1-dark)
  3. Chroma - Brightness/intensity
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41
Q

10YR 5/3 is an example of a _________ color

A

Munsell

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42
Q

T/F: Volcanic rocks can make soil black/dark

A

True

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43
Q

Does dark soil always mean that is organic matter?

A

No

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44
Q

Name the process: very little presence of oxygen is called ________ while an abundance of water + oxygen + iron is called ________

A
  1. Reduction
  2. Oxidation
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45
Q

T/F: Volcano soils are not rich or fertile due to their lack of organic matter

A

False

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46
Q

Is agriculture successful in places with volcano soils? Why?

A

Yes because they have rich & fertile soils with organic matter that cannot breakdown (so it stays still)

47
Q

Pine trees add ______ to soil profiles

A

Acids

48
Q

Pure sands come from _________

A

Quartz

49
Q

T/F: Calcium/sodium deposits can make white layers within soils

A

True!

50
Q

Soil structure is made up of the arrangement of sand, silt, clay and organic matter which forms into ____________

A

Aggregates

51
Q

What are aggregates?

A

Smaller particles that come together that form a larger particle

52
Q

Why do aggregates form/come together?

A

Because of soil glue (sticky stuff)

53
Q

FITB: Aggregate formations can be in a ________, _______ or ________ form

A
  1. Physical
  2. Chemical
  3. Biologic
54
Q

FITB: Aggregates have the ability to shrink/_____, and ______/thaw

A
  1. Swell
  2. Freeze
55
Q

What is flocculation?

A

The attraction of 2 particles together due to charges/the mutual attraction among clay and organic molecules (like magnets)

56
Q

Aggregate formation dispersion (breaking apart the structure) occurs with which common element?

A

Sodium

57
Q

FITB: Aggregate formation can occur with exudate, _______ or living matter

A

Residue

58
Q

What are the 5 main structural shapes of soils?

A
  1. Granular - found at surface
  2. Blocky - found underground
  3. Platy - flat, sign of compaction occurring
  4. Prismatic/Columnar - forms in lower B/C horizons, lots of clay, column-like
  5. Structureless - Single grain, massive clays that are random + chunky
59
Q

What are the 5 factors that affect Bulk Density?

A
  1. Organic matter
  2. Poor aggregation
  3. Grain size
  4. Soil flora + fauna
  5. Depth of sample
60
Q

What is porosity?

A

The amount of empty space found within soils

61
Q

MC: The amount of empty space (porosity) in clays is…
A. Poorly aggregated
B. Somewhat aggregated
C. Well-aggregated
D. Compacted

A

C. Well-aggregated

62
Q

Do clays hold more or less organic matter?

A

More

63
Q

Are the pores in clays smaller or larger? (Consider particle size and if it can be seen with the naked eye)

A

Smaller (more pore space)

64
Q

MC: The amount of empty space (porosity) in sands is…
A. Poorly aggregated
B. Somewhat aggregated
C. Well-aggregated
D. Compacted

A

A. Poorly aggregated

65
Q

Does sand hold more or less organic matter?

A

Less (remember that plants can’t live in sandy soils)

66
Q

Is the pore space in sand less or more?

A

Less

67
Q

Are sand particles small or large?

A

Large

68
Q

Low %’s of pore space indicate that what process is occurring within the soil?

A

Compaction

69
Q

FITB: As % pore space goes down, bulk density goes ___

A

Up

70
Q

FITB: As % pore space goes up, bulk density goes _____

A

Down

71
Q

What is the numerical value for Particle Density?

A

2.65 g/cm³

72
Q

What kind of soil is bulk density composed of?

A

Dry soil

73
Q

What is Bulk Density?

A

The weight of a soil in a known volume

74
Q

What is Soil Pore Space?

A

The % of volume occupied by air & water

75
Q

Bulk Density includes solid + ______ fractions

A

Pore

76
Q

Why is Bulk Density important?

A

For agriculture

77
Q

TOT: If you have a higher Bulk Density, that means that you have more/less compaction

A

More

78
Q

TOT: If you have a lower Bulk Density, that means that you have more/less compaction

A

Less

79
Q

What is the ideal Bulk Density numerical range for plant growth?

A

1.2-1.4

80
Q

TOT: When you have higher compaction, it is harder/easier to have air and water pass through the soil

A

Harder

81
Q

T/F: Minerals are less dense than water

A

False

82
Q

T/F: Organic matter is more dense than water

A

True

83
Q

What are the 5 soil forming factors?

A
  1. Climate
  2. Biota
  3. Relief (topography)
  4. Parent material
  5. Time
84
Q

What is climate?

A

The change in atmospheric conditions

85
Q

T/F: Climate does not influence erosion, plant success or mineral breakdown

A

False

86
Q

When we talk about relief being one of the 5 soil forming factors, what are we really referring to? (Don’t say topography)

A

How hilly/flat your landscape is

87
Q

Relief includes what 5 characteristics?

A
  1. Slope
  2. Length
  3. Landscape position
  4. Elevation
  5. Aspect
88
Q

FITB: One of the soil forming factors is time. Time controls the amount of _________ occurring

A

Interactions

89
Q

Time includes what 3 characteristics?

A
  1. Climate
  2. Vegetation
  3. Human interactions
90
Q

Biota is composed of _________ __________.

A

Living organisms

91
Q

What are 4 examples of biota?

A
  1. Microbes
  2. Animals
  3. Plants
  4. Humans
92
Q

T/F: Microbes participate in biological processes such as the act of nitrification

A

True

93
Q

FITB: Microbes _______ organic matter

A

Nitrify

94
Q

FITB: Earthworms create _______ in their guts

A

Calcite

95
Q

What is Pedoturbation?

A

The physical disturbance & mixing of soil horizons (performed by worms and roots)

96
Q

T/F: Humans were a major force of soil development in the past but no longer are today

A

False

97
Q

What are the 4 characteristics of Human Influences?

A
  1. Building development
  2. Waste
  3. Agriculture
  4. Climate
98
Q

What is parent material?

A

The material and process from which soil develops

99
Q

What is weathering?

A

The deterioration of rock due to breakdown processes

100
Q

What are the 2 types of weathering?

A
  1. Physical (mechanical)
  2. Chemical
101
Q

FITB: A physical type of weathering is known as ______’s sandpaper, which is more commonly known as _______ & ________

A
  1. Nature’s
  2. Impact & abrasion
102
Q

What are 3 things that can cause Impact & abrasion to occur?

A
  1. Wind
  2. Water
  3. Ice
103
Q

What is meant by impact and abrasion?

A

Carried particles that scrape against a substance (like a rock)

104
Q

How do grooves (a physical weathering type) form?

A

When a bigger rock scrapes against bedrock (in which ice then picks it up and carries it across)

105
Q

Is Wedging a physical/chemical type of weathering?

A

Physical

106
Q

How does wedging occur?

A

When water enters into cracks of rocks and the water within freezes, the rock expands

107
Q

T/F: Wedging affects small and larger objects

A

False; just larger objects

108
Q

T/F: Wedging can occur through plants and trees

A

True

109
Q

Exfoliation is an example of a physical/chemical type of weathering?

A

Physical

110
Q

What does Exfoliation mean?

A

The loss of the outer layer of a rock due to expansion

111
Q

Stratification occurs in which type of rock?
A. Limestone
B. Granite
C. Coal
D. Quartz
E. Bedrock

A

E. Bedrock

112
Q

T/F: Stratification does not need to have some movement (sunlight)

A

False

113
Q

Stratification is associated with which type of physical weathering?
A. Impact & abrasion
B. Hydration
C. Grooves
D. Exfoliation

A

D. Exfoliation

114
Q
A

Soil Science (2 decks)

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