Soil Science Final Flashcards
1
Q
True or Flase: Most of the organic matter in soils are found in the B horizon
A
False
2
Q
True or False: Soil is considered “consolidated” material
A
False
3
Q
True or False: Fast cooling will result in coarse texture
A
False
4
Q
True or False: According to Bowen, isolated silicate minerals like olivines crystallize at very high temperatures
A
True
5
Q
True or False: Metamorphic rocks formed with significan differential stress will have foliation
A
True
6
Q
True or False: The binding effectivness of microbial gums is lesser than that of clay and organic matter
A
False
7
Q
True or False: Puddling is an example of massive structureless soil
A
True
8
Q
True or False: On the average, a loam would have a higher total porosity than a loamy sand
A
True
9
Q
True or False: Addition of organic matter to soil will help increase bulk density
A
False
10
Q
True or False: Soil texture is a dynamic property that is rather easy to change, whereas soil structure is a static soil property which changes very little
A
False
11
Q
True or False: The class of structure refers to the shape of the peds
A
False
12
Q
True or False: Soils formed under coniferous forest will be more acid in the A horizon compared to those formed under deciduous forest because their leaves contain less Mg
A
True
13
Q
True or False: As one moves way from the equator soils develop more reddish hues
A
False
14
Q
True or False: Compaction of soil has no effect on porosity
A
False
15
Q
True or False: Under actual field conditions soil moisture content determines more than any other factor the energy required to raise the temperature of soils
A
True
16
Q
True or False: Water in saturated soils is under positive pressure
A
True
17
Q
True or False: Soil Taxonomy has 6 categories, the most specific of the categories is series
A
True
18
Q
True or False: At the hygroscopic coefficient most of the microspores are filled with water
A
False
19
Q
True or False: The soil ability to hold water is inversely proportional to the size of its pores
A
True
20
Q
True or False: Gravitational water is held in macrospores
A
True
21
Q
True or False: When water is attracted either by soil or ions and solutes, the free energy is increased
A
False
22
Q
The most common product of chemical weathering of feldspar is
A
clay minerals
23
Q
Sediments with diameter greater than 2mm will be classified as
A
Gravel
24
Q
A vertical cross section of a soil showing contrasting layers is called a soil
A
profile
25
Regional metamorphism of shale by compressive stress would produce which of the following sequences as temperature rises
slate, phyllite, schist, gneiss
26
The Mohs sclae measures the ____________ of a mineral
Hardness
27
Which of the following fine grained igneous rocks have the lowest quartz content
basalt
28
The parent rock for marble is
limestone
29
The parent rock for quartzite is
quartz and sandstone
30
The subsoil is generally equivalent to which horizon
B
31
Pedology is the schience is
considered the soil as a natural bod and places minor emphasis on its use
32
Soil as a medium of plant growth is a/an
Edaphological
33
Pyroxenes belongs to the
single chain
34
Apatite is a non-silicate mineral of great agricultural importance because it is a principal source of the essential element
P
35
This carbonate mineral contains calcium and magnesium
dolomite
36
Framework silicates include
quartz and fieldspars
37
Hematite is a secondary mineral with this element
Iron
38
Which one of the following are evaporites?
Halite, Gypsum, Sylvite
39
This equation KAlSi3O3 + H2O ----> HAlSi3O3 + KOH is
hydrolysis usually occurring in a humid climate
40
A pedon may range from
1 to 10m^2
41
The most common elements in the earth's crust, in order of decreasing abundance are
Oxygen, silicon, aluminum
42
Rocks that have undergone heat and pressure changes are classified as
metamorphic
43
The color of a powdered mineral is called
streak
44
Soil is a dynamic ____________ having properties due to the actions of climate and biotic activity, as modified by topography, acting on parent material over time
unconsolidated material
45
A common sulfate mineral is
gypsum
46
Only _________ elements account for 98.5% of the earth's crust by weight
eight
47
Sheet silicates include
micas and clays
48
The dominant elements in ferromagnesian silicates are
iron and magnesium
49
Chemical weathering in a cool and dry setting is
slow
50
The most common elements in the earth's rust, in order of decreasing abundance are
Oxygen, silicon, aluminum
51
A secondary eqivalent of quartz is
chert
52
Olivine is a _______________ silicate mineral
isolated
53
Which two of the following are detrital or clastic sedimentary rock?
breccia and sandstone
54
A sandstone with varying amounts of feldspars and quartz is called
arkose
55
A common carbonate mineral is
calcite
56
______________ is common sedimentary rock with rounded gravel sized particles
conglomerate
57
The biochemically weathered protion of the upper regolith is the
solum or soil
58
A reasonable value for the volume of organic matter in a soil is about
5%
59
Basalt and Gabbro are different in
texture
60
The unconsolidated material above the bedrock is known as the
regolith
61
What type of equation is this: 2Fe2O3 + 3H2O -----> 2Fe2O3*3H2O
Hydration
62
What type of equation is this: 4FeO + O2 -----> 2FeO3
oxidation
63
In humid soils which of the following statements would adequately describe the general soil structure patterns occurring in a soil profile?
a granular aggregation in the surface horizon with a blocky type of structure in the subsoil
64
A soi separate is defined by
its size
65
Which has the least specific surface
sand
66
The range in bulk density for mineral soil is about _________ gm/cm^3
67
Other factors being equal, we expect to find
More total organic in a grass derived soil than in a soil developed under forest vegetation
68
If 400cm^3 of a soil weighs 500g, the bulk density is
1.25 Mg/m^3
69
A soil weighing 90g had a total volume of 50 cm^3. Assuming that the particle density of typical mineral soil of 2.65 g/cm^3, the % pore space of this soil will be
32%
70
Which of the following terms refers to the physical condition of the soil in its reaction to plant growth?
tilth
71
Which type of structure will typically be found in surface (A Horizon) soils in Arizona?
granular
72
Commonly soil tillage is for the purpose of
1) controlling weeds
2) managing crop residue
3) altering the soil's physical qualities
73
In making a particle size analysis, the 40 second reading was 20g and the two hour reading was 15g. If a 50 gram sample was used, the silt content is
10%
74
The ability of soil to resist crushing is known as
consistence
75
Minimum tillage is a type of tillage which
considerably reduces the number of soil manipulation operations
76
The bulk density of a soil generally __________ with depth
increases
77
On the average, the bulk density of soils
varies inversely with porosity
78
The hydrometer used in the particle size analysis (mechanical analysis) directly measures the
grams of silt and clay
79
Soil structure refers to the
arrangement of primary soil particles to form aggregates
80
Sand particles in the USDA system range in size from
0.05 - 2mm
81
Different soils formed from the same parent material but at different topography are known as
Catena
82
Old soils will be mostly probably classified as
ultisols
83
A soil has a bulk density of 1.69 gm/cm^3 and a particle density of 2.6 gm/cm^3. Its oven dry weight is 80 gm. The porosity of the soil is _______% by the volume
35
84
Loess is a glacial deposit that has been moved into place by
wind
85
A moraine is associated with
glaciers
86
The two climatic variables have the greatest influence on soil formation are
precipitation and temperature
87
The geological agent responsible for deposition alluvial parent materials is
flowing water
88
A soil texture is reported as a clay loam soil. Therefore it
forms a strong ribbon between 2.5 and 5cm
89
Illuviation is an example of
translocation
90
A group of mineral soil paticles with a definite upper and lower size limit defines
a soil separate
91
A soil is said to have a minsell color chart of 7.5 YR 2/6. The 6 represents the
chroma
92
Soil colors of grey and blue indicates
poor internal drainage
93
The dominant wavelength of light reflected determines the color
hue
94
How many possible textural class names are there
12
95
When one knows that a given soil horizon has a loam texture, one knows for sure that the horizon
contains less than 50% clay
96
If a soil has 22% sand, 5% organic matter and 60% silt, the clay content of this soil would be given as
18%
97
Material that has been eroded down hill not in a channel and accumulated at the base of a slope is classified as the following kind of transported material
colluvial
98
It is important for all land managers to know something about rocks and minerals because
In the field some soil properties such as texture, clay type and pH are influenced by the parent rock
99
Surface soils are usually ________ than subsoils
darker in color
100
When a 100 gram soil sample is used to make a particle size analysis and 40 second reading is 10 g/L, this means that
the percentage of sand is 90
101
The five factors of soil formation are
climate, biotic factors, time, parent materials, and topography
102
Leaching is an example of
losses
103
Humification is an example of
transformation
104
Water molecules
have an assymetrical charge distributuon
105
Soil stored plant available water is
part of the water in micropores
106
The forces active in causing cappilary rise of water are
adhesion and cohesion
107
The attraction of water molecules to soil is reffered to as
adhesion
108
The exchange of gases by diffusion betwee the atmosphere and the soil air is due to differences in
partial pressure of individual gases in soil air and atmosphere
109
In unsaturated soil the soil moisture potential will most likely be
negative
110
The following are laboratory methods used for determining soil water
pressure plates, gravimetric methods and pressure membranes
111
The major component of the total soil water potential in unsaturated soil is the ________ potential
matric
112
The major component of soil water in wetland soils is the ______________ potential
gravitational
113
Much oxygen from the soil air is used in
respiration
114
Adding salt to a soil solution increases its
osmotic potential
115
The major basis for classification of soil by the comprehensive soil classification system is
properties of horizons present
116
The concentration of CO2 in the soil atmosphere is _______ than CO2 concentration in air
greater
117
Of the soil properties listed, the one having the greatest effect on soil aeration is
texture
118
A well aerated soil will be characterized by a relative abundance of _______________
Fe^3+, NO3-, SO4^2-
119
______________________ is the process by which individual gases move in response to differences in partial pressure of the gas
diffusion
120
Which of the following is not a major factor in determining the soil aeration status?
nitrogen gas
121
The specific heat of a dry soil is
aout 1/5 as that for water
122
Soil CO2 increases when
organic matter additions increases
123
The soils of the order vertisols are distinguished from other orders by
swelling clay content
124
The soil moisture regime of an aquoll is
aquic
125
The mechanism of gas exchange in soils that prevents oxygen deficiency and carbon dioxide toxicity is
soil aeration
126
Which of the following crops will be is not well suited for well aerated soils
cranberries
127
A soil which has an aridic moisture regime and an ochric or anthropic epipedon may most probably be classified as an
aridisol
128
About _________ of radiant energy is used for photosynthesis
3%
129
Plant roots require a supply of oxygen in the soil air carry out
respiration
130
The exchange of gases by diffusion between the atmosphere and the soil air is due to differences in
partial pressure of individual gasses in soil air and atmosphere
131
___________ bacterial will be the dominant bacteria in soils with temoeratures between 0 and 5C
Cryophyllic
132
Soil temperature is important because it helps
seed germination and microbial metabolism
133
Soils that have agillic or kandic horizons and base saturation of greater than 35% will be classified as
alfisols
134
A Bt horizon will be probably closest to the ___________ subsurface horizon
argillic
135
Under poorly-drained soils __________________ will constitute the major microbial population
anaerobes
136
The order nae of miami series, typic hapludalf (fine loamy, mesic, mixed) is
alfisol
137
Subsoil horizons containing an accumulation of humus, iron and aluminum are called
spodic
138
An epipedon that thick, dark colored, high in bases, has a strong structure will be classified as
mollic
139
Typic hapludalf is a soil _________________ name
subgroup
