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AGR 345 Soil Science > Exam 1 > Flashcards

Exam 1 Flashcards

Chapters 1-3 (142 cards)

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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
4 processes that make soils
1) transformations - weathering 2) translocations - moving 3) additions - organic matter input, soil from wind erosion 4) losses - leaching and erosion
26
soil horizon
roughly parallel layers in the soil with varying composition and properties
27
soil profile
2D rep. of a vertical section of soil from the surface to deepest layers
28
soil master horizons
O, A, B, C
29
A horizon
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
30
B horizon
lighter color, more clay, less OM, accumulates material lost from from above, zone of translocation, good soil structure, high reactivity, strong color (clay), illuvial
31
C horizon
weakly altered by soil forming processes, resembles parent material
32
E horizon
between A+B in Western KY - lighter color, leaching, zone of leaching, Fe + Al oxidizes, elluvial
33
five soil forming factors
1) parent material 2) climate 3) organisma (vegetation, fauna, and soil biota) 4) relief (landforms and topography) 5) time
34
five transported parent materials
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
35
what is the most common parent material in western KY
loess
36
glacial till
morianes, end moraine, drumlins
37
sorted parent materials
water (outwash and lacustrine=former lake bottom), wind, and sand
38
effect of temperature on soil formation
warmer = faster cooler = slower
39
effect of precipitation on soil formation
higher rainfall = greater leaching
40
why does soil get older faster in tropical climates?
the rainfall amounts, leaching, and the fact that the soil never gets to rest because of year-round cropping, temperature
41
leaching zone
determined by the location calcium carbonate in the soil profile
42
evapotranspiration
the amount of effective rainfall that can cause soil leaching
43
four organism soil forming factors
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
44
three relief / topography soil forming factors
1) catena 2) drainage classes 3) erosion and deposition
45
catena
a series of soils with different horizons due to differences in their depth to the water table
46
four drainage classes
1) well-drained 2) moderately well-drained 3) somewhat poorly drained 4) poorly drained
47
summit
minimum erosion and maximum soil development
48
backslope
similar to summit unless slope is >20%
49
shoulder
greatest erosion, least water infiltration, greatest runoff, minimal soil development
50
footslope
dark soil color, good soil fertility, high amount of water, may have greatest leaching, deposition of materials from upslope
51
aspect
direction the slope faces
52
hillslope
N facing slopes = more soil development S facing slopes = less soil development
53
the age of a soil is determined by its _________ not the actual ______________
development; number of years it has been developing
54
six young soils
1) Entisols - ent 2) Inceptisols - ept 3) Gelisols - el 4) Andisols - and 5) Aridisols - id 6) Vertisols - ert
55
three old soils
1) Ultisols - ult 2) Oxisols - ox 3) Spodosols - od
56
organic soil
Histosols - ist *must have more than 20% OM
57
two mature soils
1) Mollisols - ol 2) Alfisols - alf
58
climate factors that slow soil formation
low rainfall, low humidity, cold temperature
59
biota factor that slow soil formation
mixing by animals or man
60
what four things happens to soil with time?
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
oldest soil in the U.S.
Durixeralf (California) and/or Petroargid (New Mexico and Arizona)
62
R horizon
bedrock (limestone)
63
O horizon
too soft for crops to grow, primarily composed of organic matter, often called peat, extremely similar to potting soil
64
The most common parent material in western KY is loess (said like loss), where does it come from?
eolian transported by wind
65
soil formation leads to...
soil horizonation
66
the fragipan layer
- 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
seven criteria to characterizing soil horizons
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
acronym for soil forming factors
CORPT
69
Hans Jenny
famous for soil forming factors/building processes
70
soil science criteria of soil profile
top 5 feet
71
solum
horizons A, E, and B
72
KY state soil series
Crider silt loam
73
a subhorizon
highly decomposed OM
74
e subhorizon
moderately decomposed OM
75
i subhorizon
slightly decomposed OM
76
g subhorizon
wet for long periods of time
77
h subhorizon
humic; organic matter accumulation
78
o subhorizon
Fe and Al oxide buildup
79
p subhorizon
plowing or disturbance
80
r subhorizon
bedrock is weathered or soft
81
s subhorizon
OM and Fe + Al oxides accumulation
82
t subhorizon
accumulation of clay
83
w subhorizon
changed by weathering
84
x subhorizon
fragipan
85
Ap (common in agriculture)
surface horizon with plowing or disturbance
86
Bg
subsoil that is wet for long periods of time
87
Bt
subsoil that has accumulation of clay
88
Ax
surface horizon with fragipan
89
Bx
subsoil with fragipan
90
Bw
subsoil that has been changed by weathering
91
seven categories of soil taxonomy
1) order 2) suborder 3) great group 4) subgroup 5) family 6) series- common name 7) phase or type
92
twelve soil orders
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
oldest soil order
Oxisols
94
two soil orders commonly found in tropical areas
oxisols and ultisols
95
soil order developed under grasslands
mollisols
96
soil order developed under forest
alfisols
97
soil order considered organic soil
histosols
98
soil order developed under volcanic eruptions
andisols
99
soil order that has crazy clay
vertisols
100
soil order developed in weathered areas
oxisols
101
older, weathered soils may have a _______ or ______ color below the surface of the soil
yellow; red
102
andisols
- young - low bulk density - high porosity - wind erosion problem - amorphous clays - highly productive and good for rice farming - Hawaii
103
entisols
- only A horizon over C, missing B - found on or with: inert parent materials, very poor limestone, active floodplains, poor climate conditions
104
inceptisols
- immature but more developed than entisols - weak development - tundra, mountains, etc.
105
aridisols
- develop in areas with only short wet periods - little leaching of base cations - low OM, salt accumulations
106
gelisols
- young, little development - cold, frozen most of the year - missing A and B horizons - permafrost
107
vertisols
- 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
mollisols
- 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
famers use...
soil series
110
alfisols
- mature soil - well developed A, (E), B, and C horizons - greater than 35% base saturation in Bt horizon - forest soils
111
ultisols
- 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
spodosols
- old soil - high sand content - highly leached - very acidic, low % BS - very infertile
113
oxisols
- 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
histosols
- 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
youngest soil
entisols
116
boralf
alfisols
117
argid
aridisols
118
fluvent
entisols
119
hemist
histosols
120
xerult
ultisols
121
aquert
vertisols
122
ochrept
inceptisols
123
udoll
mollisols
124
turbel
gelisols
125
vitrand
andisols
126
torrox
oxisols
127
aquod
spodosols
128
oldest soil suborder
Torrox
129
youngest soil suborder
fluvent
130
volcanic eruption
vitrand
131
high sand
aquod
132
crazy clays
aquert
133
needs drainage, too wet
hemist
134
permafrost and found in Alaska
turbel
135
older than the youngest one
ochrept
136
commonly found in TX
argid
137
Om > 60%
hemist
138
best for farming
udoll
139
from prairie
udoll
140
developed under forest
boralf
141
commonly found in Hawaii and Japan
vitrand
142
uniform layers
torrox

AGR 345 Soil Science (3 decks)

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