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AGR 345 Soil Science > Exam 1 > Flashcards

Exam 1 Flashcards

Chapters 1-3

1
Q

soil functions

A

soils deliver ecosystem services enabling life on earth

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2
Q

importance of soil

A

plant production, matter cycling, habitat for biological activity (biodiversity), filter and buffer for water, carbon sequestration

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3
Q

ten threats to soil sustainability

A

1) erosion
2) organic carbon loss
3) nutrient imbalances
4) acidification
5) contamination
6) waterlogging
7) compaction
8) soil sealing
9) salinization
10) loss of biodiversity

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4
Q

five concepts of soil

A

1) mixture of solids, liquids, and gases
2) various colors (iron gives soil a red color)
3) formed from parent materials
4) soil has structure
5) soil has horizons

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5
Q

ideal composition

A

25% air, 25% water, 45% minerals, 5% organic matter

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6
Q

six roles of soil

A

1) medium for plant growth
2) natural body
3) regulator of water supplies
4) recycler of raw materials
5) habitat for soil organisms
6) an engineering medium

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7
Q

uses of soil

A

Native Americans used earth colors as body paints; cosmetics

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8
Q

three types of soil degradation

A

physical, chemical, and biological

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9
Q

physical soil degradation

A

caused by tillage or compaction from heavy equipment

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10
Q

chemical soil degradation

A

overapplication or misuse of fertilizers and pesticides

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11
Q

biological soil degradation

A

overgrazing that leads to compaction, less perennial root systems, and introduction of invasive species

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12
Q

what percentage of soil degradation is caused by agricultural practices?

A

39% (which is the highest)

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13
Q

three strategies to prevent/reduce degradation

A

1) the use of soil cover
2) improve landscape biodiversity
3) the use of living roots in agricultural practices

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14
Q

high functioning soils

A

closely related to soil health

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15
Q

soil health

A

the continued capacity of a soil to function as a vital, living ecosystem that sustains plants, animals, and humans

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16
Q

four soil health principles

A

1) maximize living roots
2) reduced tillage
3) maximize soil covers / cover crops
4) maximize biodiversity

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17
Q

soil microbes have key roles in…

A

nutrient cycling

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18
Q

five benefits of soil

A

1) medium for plant growth
2) regulator of water supplies
3) recycler of raw materials
4) habitat for soil organisms
5) engineering medium

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19
Q

how does soil act as a natural filter for water?

A

1) the movement of water, minerals, and organic materials filter and detoxify precipitation
2) soil can clean sewage
3) microorganisms can consume wastewater in drained fields

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20
Q

why is soil considered a microecosystem?

A

soil provides a habitat for the greatest diversity of microorganism species than any other environment on the earth

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21
Q

what materials can be made from clays?

A

ceramics and drilling fluid that is used by the oil industry

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22
Q

soils are like fingerprints because…

A

every type of soil has unique properties and can be traced back to its origin

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23
Q

four basic aggregate shapes

A

granular, blocky, prismatic, and platy

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24
Q

soil color can be used to determine…

A

whether a soil has high or low OM, is wet or dry, has aerobic (oxidized) or anaerobic (reduced) condition, and has a high or low iron content

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25
Q

4 processes that make soils

A

1) transformations - weathering
2) translocations - moving
3) additions - organic matter input, soil from wind erosion
4) losses - leaching and erosion

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26
Q

soil horizon

A

roughly parallel layers in the soil with varying composition and properties

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27
Q

soil profile

A

2D rep. of a vertical section of soil from the surface to deepest layers

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28
Q

soil master horizons

A

O, A, B, C

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29
Q

A horizon

A

dark color, minerals, best for plant growth, decomposed OM, 90% food production from A horizon, zone of gas and water exchange, high biotic activity and plant roots

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30
Q

B horizon

A

lighter color, more clay, less OM, accumulates material lost from from above, zone of translocation, good soil structure, high reactivity, strong color (clay), illuvial

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31
Q

C horizon

A

weakly altered by soil forming processes, resembles parent material

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32
Q

E horizon

A

between A+B in Western KY - lighter color, leaching, zone of leaching, Fe + Al oxidizes, elluvial

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33
Q

five soil forming factors

A

1) parent material
2) climate
3) organisma (vegetation, fauna, and soil biota)
4) relief (landforms and topography)
5) time

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34
Q

five transported parent materials

A

1) water (alluvium)
2) wind (sand or silt)
3) gravity (colluvium)
4) ice (glacial drift - materials transported by ice or glaciers)
5) loess -> silt -> silt loam

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35
Q

what is the most common parent material in western KY

A

loess

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36
Q

glacial till

A

morianes, end moraine, drumlins

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37
Q

sorted parent materials

A

water (outwash and lacustrine=former lake bottom), wind, and sand

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38
Q

effect of temperature on soil formation

A

warmer = faster
cooler = slower

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39
Q

effect of precipitation on soil formation

A

higher rainfall = greater leaching

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40
Q

why does soil get older faster in tropical climates?

A

the rainfall amounts, leaching, and the fact that the soil never gets to rest because of year-round cropping, temperature

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41
Q

leaching zone

A

determined by the location calcium carbonate in the soil profile

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42
Q

evapotranspiration

A

the amount of effective rainfall that can cause soil leaching

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43
Q

four organism soil forming factors

A

1) animals - soil mixing
2) vegetation - addition of OM
3) prairie - OM added to upper 2 feet of soil due to fibrous roots
4) forest - OM added to upper 4 inches due to yearly leaf fall

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44
Q

three relief / topography soil forming factors

A

1) catena
2) drainage classes
3) erosion and deposition

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45
Q

catena

A

a series of soils with different horizons due to differences in their depth to the water table

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46
Q

four drainage classes

A

1) well-drained
2) moderately well-drained
3) somewhat poorly drained
4) poorly drained

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47
Q

summit

A

minimum erosion and maximum soil development

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48
Q

backslope

A

similar to summit unless slope is >20%

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49
Q

shoulder

A

greatest erosion, least water infiltration, greatest runoff, minimal soil development

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50
Q

footslope

A

dark soil color, good soil fertility, high amount of water, may have greatest leaching, deposition of materials from upslope

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51
Q

aspect

A

direction the slope faces

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52
Q

hillslope

A

N facing slopes = more soil development
S facing slopes = less soil development

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53
Q

the age of a soil is determined by its _________ not the actual ______________

A

development; number of years it has been developing

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54
Q

six young soils

A

1) Entisols - ent
2) Inceptisols - ept
3) Gelisols - el
4) Andisols - and
5) Aridisols - id
6) Vertisols - ert

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55
Q

three old soils

A

1) Ultisols - ult
2) Oxisols - ox
3) Spodosols - od

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56
Q

organic soil

A

Histosols - ist
*must have more than 20% OM

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57
Q

two mature soils

A

1) Mollisols - ol
2) Alfisols - alf

58
Q

climate factors that slow soil formation

A

low rainfall, low humidity, cold temperature

59
Q

biota factor that slow soil formation

A

mixing by animals or man

60
Q

what four things happens to soil with time?

A

1) loss of nutrients (bases) = lower pH or soil becomes more acidic
2) increase in concentration of iron or soil becomes redder
3) increase in clay content or old soils have more clay
4) deeper weathering into parent material

61
Q

oldest soil in the U.S.

A

Durixeralf (California) and/or Petroargid (New Mexico and Arizona)

62
Q

R horizon

A

bedrock (limestone)

63
Q

O horizon

A

too soft for crops to grow, primarily composed of organic matter, often called peat, extremely similar to potting soil

64
Q

The most common parent material in western KY is loess (said like loss), where does it come from?

A

eolian transported by wind

65
Q

soil formation leads to…

A

soil horizonation

66
Q

the fragipan layer

A
  • unique to western KY
  • after B horizon
  • the thicker the fragipan, the worse the crop production because it is hard for crops and water to penetrate it
  • hard in nature but very brittle
67
Q

seven criteria to characterizing soil horizons

A

1) color
2) texture- sandy loam, clay loam, etc.
3) density- how compact or loose
4) structure- granular, blocky, etc.
5) organic matter
6) mineralogy- presence of iron, calcium, etc.
7) chemistry- relates to pH

68
Q

acronym for soil forming factors

A

CORPT

69
Q

Hans Jenny

A

famous for soil forming factors/building processes

70
Q

soil science criteria of soil profile

A

top 5 feet

71
Q

solum

A

horizons A, E, and B

72
Q

KY state soil series

A

Crider silt loam

73
Q

a subhorizon

A

highly decomposed OM

74
Q

e subhorizon

A

moderately decomposed OM

75
Q

i subhorizon

A

slightly decomposed OM

76
Q

g subhorizon

A

wet for long periods of time

77
Q

h subhorizon

A

humic; organic matter accumulation

78
Q

o subhorizon

A

Fe and Al oxide buildup

79
Q

p subhorizon

A

plowing or disturbance

80
Q

r subhorizon

A

bedrock is weathered or soft

81
Q

s subhorizon

A

OM and Fe + Al oxides accumulation

82
Q

t subhorizon

A

accumulation of clay

83
Q

w subhorizon

A

changed by weathering

84
Q

x subhorizon

A

fragipan

85
Q

Ap (common in agriculture)

A

surface horizon with plowing or disturbance

86
Q

Bg

A

subsoil that is wet for long periods of time

87
Q

Bt

A

subsoil that has accumulation of clay

88
Q

Ax

A

surface horizon with fragipan

89
Q

Bx

A

subsoil with fragipan

90
Q

Bw

A

subsoil that has been changed by weathering

91
Q

seven categories of soil taxonomy

A

1) order
2) suborder
3) great group
4) subgroup
5) family
6) series- common name
7) phase or type

92
Q

twelve soil orders

A

1) Andisols
2) Entisols
3) Inceptisols
4) Aridisols
5) Gelisols
6) Vertisols
7) Mollisols
8) Alfisols
9) Ultisols
10) Spodosols
11) Oxisols
12) Histosols

93
Q

oldest soil order

A

Oxisols

94
Q

two soil orders commonly found in tropical areas

A

oxisols and ultisols

95
Q

soil order developed under grasslands

A

mollisols

96
Q

soil order developed under forest

A

alfisols

97
Q

soil order considered organic soil

A

histosols

98
Q

soil order developed under volcanic eruptions

A

andisols

99
Q

soil order that has crazy clay

A

vertisols

100
Q

soil order developed in weathered areas

A

oxisols

101
Q

older, weathered soils may have a _______ or ______ color below the surface of the soil

A

yellow; red

102
Q

andisols

A
  • young
  • low bulk density
  • high porosity
  • wind erosion problem
  • amorphous clays
  • highly productive and good for rice farming
  • Hawaii
103
Q

entisols

A
  • only A horizon over C, missing B
  • found on or with: inert parent materials, very poor limestone, active floodplains, poor climate conditions
104
Q

inceptisols

A
  • immature but more developed than entisols
  • weak development
  • tundra, mountains, etc.
105
Q

aridisols

A
  • develop in areas with only short wet periods
  • little leaching of base cations
  • low OM, salt accumulations
106
Q

gelisols

A
  • young, little development
  • cold, frozen most of the year
  • missing A and B horizons
  • permafrost
107
Q

vertisols

A
  • must have more than 30% montmorillonite
  • high expansion and contracting, self mixing
  • poor horizonation except for deep A horizon
  • very difficult management
  • gilgai topography
108
Q

mollisols

A
  • greater than 50% BS
  • usually grassland soils
  • subhumid to semiarid; cold to hot
  • very fertile and productive, most prized soils in the world
  • high OM
109
Q

famers use…

A

soil series

110
Q

alfisols

A
  • mature soil
  • well developed A, (E), B, and C horizons
  • greater than 35% base saturation in Bt horizon
  • forest soils
111
Q

ultisols

A
  • well developed horizonation
  • found in southern states and tropical areas
  • acidic, < 35% BS
  • productive when managed well
  • high in 1:1 clays and has crazy clays
  • orange color
112
Q

spodosols

A
  • old soil
  • high sand content
  • highly leached
  • very acidic, low % BS
  • very infertile
113
Q

oxisols

A
  • highly weathered
  • tropical soils
  • low activity clays
  • Fe and Al oxides
  • very strong soil (good for engineering)
  • very low % BS
  • not much difference in horizons
114
Q

histosols

A
  • organic soils
  • high OM, sometimes 0.001-60% clay
  • usually saturated part of the year
  • high water and nutrient holding
  • low bulk density (very soft)
115
Q

youngest soil

A

entisols

116
Q

boralf

A

alfisols

117
Q

argid

A

aridisols

118
Q

fluvent

A

entisols

119
Q

hemist

A

histosols

120
Q

xerult

A

ultisols

121
Q

aquert

A

vertisols

122
Q

ochrept

A

inceptisols

123
Q

udoll

A

mollisols

124
Q

turbel

A

gelisols

125
Q

vitrand

A

andisols

126
Q

torrox

A

oxisols

127
Q

aquod

A

spodosols

128
Q

oldest soil suborder

A

Torrox

129
Q

youngest soil suborder

A

fluvent

130
Q

volcanic eruption

A

vitrand

131
Q

high sand

A

aquod

132
Q

crazy clays

A

aquert

133
Q

needs drainage, too wet

A

hemist

134
Q

permafrost and found in Alaska

A

turbel

135
Q

older than the youngest one

A

ochrept

136
Q

commonly found in TX

A

argid

137
Q

Om > 60%

A

hemist

138
Q

best for farming

A

udoll

139
Q

from prairie

A

udoll

140
Q

developed under forest

A

boralf

141
Q

commonly found in Hawaii and Japan

A

vitrand

142
Q

uniform layers

A

torrox

AGR 345 Soil Science (3 decks)

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