Soils (1&2&3&4&5&6&7&8&10)
A soil profile consists of:
The set of layers seen in a vertical cross section of soil
Of the following horizons, which has the highest amount of organic matter?
O
Peats will typically be found in what horizon
O
Describe the 5 master soil horizons, moving from top to bottom in a typical soil profile.
O A E B C
The negative charges associated with kaolinite clay minerals are due mostly to ___________.
OH groups on the external surface of the mineral
Which of the following soil horizons was likely found beneath a forest
Oi, A1, A2, E, Bs, Bs2, BC
Mineral classes that make up our 2:1 silicate clays include ____ like gibbsite and _______ like smecctite
Oxides, silicates
A Calcareous soil will likely have a pH ________________.
between 7.0 and 8.2
Which of the following subsurface diagnostic horizons would you expect to find in a highly weathered soil of the humid tropics?
oxic
The electronegative charge on 2:1 silicate clays is due primarily to _________.
substitution of one metallic atom for another in the crystal structure
The most weathered portion of the soil profile is the ________.
Solum
Igneous rocks can best be characterized as:
rocks formed when molten magma solidifies.
pH dependent charges account for _________% of the CEC in kaolinite.
50
Prismatic aggregates develop in ________ soils.
Arid
Ca deficiencies are uncommon in ___________ soils.
Calcareous
Granite is an example of a(n) ________.
igneous rock
Block-like aggregates are found in the ________ and _____ horizons
A and B
Which cation would you expect to be held most tightly in a soil at pH 4.5?
Al3+
You would expect to find prismatic aggregation in soils from whatg state?
Arizona
Mass per unit volume of a soil is termed ___________________.
Bulk Density
Soils with a pH of 5.0 are often deficient in _________ and _________.
Ca and Mg
Using the textural triangle, a soil with 34% sand and 33% clay belongs to the ___________ textural class.
Clay Loam
Which of the following soil samples was most likely deposited by volcanoes?
Clay soil, high in allophane
The chemical equation CaSO4 * 2H2O + 2 H2O ==> Ca^2+ + SO4^2- + 4H2O is an example of
Dissolution
Plate-like aggregates would typically be found in the ________ horizon
E
Soils with a pH of 8.0 are often deficient in ____________ and ___________.
Fe and Zn
A homeowner in Dallas (pH = 8.1) attempted to grow blueberries, but the plants were stunted and had chlorotic leaves. What is the likely problem?
Fe deficiency
Which of the following is likely to have cracks in the summer? Justify your answer.
Fine, Smectitic Thermic Udic Haplustert
Which of the following would most likely be found under a forest? Justify your answer.
Fine, Ustic Humic Cryorthod
Which of the following soils would be best for growing corn? Justify your answer.
Fine-loamy, Udic Haplustoll
A Bg horizon was most likely ________ at some point during its formation
Flooded
_______________ is an example of a noncrystalline silicate clay.
Imogolite
Brown and red colors in subsurface horizons are caused by ___________ in the soil.
Iron oxides
Base cations include _________________.
K, Mg, Ca, and Na
Which of the following statements is correct?
Lacustrine parent materials have been subject to weathering for shorter periods of time than residual parent materials nearby.
Soil macropores are ____________ 0.08 mm in diameter.
Larger than
Soil micropores are ___0.08 mm in diameter
Less than
The pH of acidic soils can be easily raised using _____________.
Lime
Using the textural triangle, a soil with 45% sand and 20% clay belongs to the _______ textural class.
Loam
A plant showing interveinal chlorosis on old growth is likely deficient in ___________.
Mg
A foundation that cracks is an example of a soil failing to provide ___________.
Physical support
Soil scientists from which country first conceived the idea that soils were natural bodies?
Russia
Texture describes the ___________ of particles in a soil.
Sizes
A soil is said to be at the Hygroscopic Coefficient when _______________.
Soil moisture levels are in equilibrium with atmospheric moisture levels
The nomenclature of Soil Taxonomy is characterized by all but which one of the following statements?
The names give a clear indication of the modes of genesis of the soil.
Hydrolysis changing plagioclase into kaolinite is an example of which of the 4 basic processes of soil formation?
Transformation
Eluviation is an example of which of the 4 basic processes of soil formation?
Translocation
Which of the following statements is NOT correct
Tropical forests protect the soil from excessive weathering
Soils in which of the following soil suborders would most likely have a prominent E horizon under the A horizon?
Udalfs
You are seeking a soil with high clay content but one that is not sticky when wet nor hard and cloddy when dry. In which of the following suborders would you most likely find this soil?
Ustox
__________ of the water in lakes and streams has come in contact with soils.
Virtually all
Shortened internodes is typical of a _________ deficiency.
Zn
A soil pedon is ____.
a three-dimensional unit that embodies the primary characteristics of an individual soil
Crops such as clover and alfalfa prefer a pH ________________.
above 7.5
A Sodic soil will likely have a pH _____________.
above 8.4
Argillic horizons are characterized by ___.
accumulation of silicate clays
N is lost from the soil through ________________.
all of the above
The transformation of gneiss into mica, quartz, and feldspar crystals is an example of:
both A and C
Humus is an important soil colloid. It differs from 2:1 type materials in all but one of the following characteristics (select the one).
capability of absorbing cations
The ability of water to stick to other water particles is termed
cohesion
The mixed angular gravel, rock, and soil found at the foot of a slope is typical of what type of parent material?
colluvial
Glacial till is a term used to describe parent materials that:
contain a heterogenous mixture of mineral debris dropped by receding glaciers
The A horizon is generally _________ because of the presence of ____________.
darker, organic matter
Ammonium acetate extractions for CEC are inaccurate in ___________ soils.
highly buffered, alkaline
In which of the following epipedons is the organic matter level generally lowest?
ochric
Plants deficient in P generally show ________________.
purple leaves
Igneous, sedimentary, and metamorphic are three ______
types of rocks
A soil has a thick black A horizon, a distinct B horizon, has reasonably stable soil structure, and was formed under grassland natural vegetation. In which suborder is it most likely classed?
udolls
In silicate clays, isomorphous substitution of a Si4+ with an Al3+ results in a net ___ negative charge for the clay mineral
-1
A soil at Hygroscopic Coefficient will have a water potential of ________ bars.
-31.0
If water on the left has a potential of -0.5 bars, it will move to the right when that soil has a water potential of ________ bars.
-5.0
A soil at saturation will have a water potential of _______ bars.
0
Liming material caught on an 8-mesh screen should be assumed to be _________ % effective.
0
In a soil with a pH of 7.0, the H+ concentration would be ______________.
1 x 10-7
In a soil with pH of 5.0, the OH- concentration would be _______________.
1 x 10-9
A soil with a pH of 5.0 would be ________ times more acidic than a soil with a pH of 8.0
1,000
A soil at saturation has water in _________ % of the soil pores.
100
The range of hues used in soil science ranges from __________ to ___________.
10R to 5Y
The CCE of CaO is _____________.
178
A soil with a bulk density of 1.24 g/cm3 would weigh ___________ lbs per cubic yard.
2090
An alkaline soil contains 20% clay and 3% humus. Calculate the CEC of this soil.
22
In a typical mineral soil, what percentage of pore space would be taken up by air?
25%
Using the CEC Principle of Charge Equivalence, which of the following would be displaced by 20 Ca2+?
30 Mg2+ + 10 H+
For a soil to be considered a clay, the soil must be at least ________ clay.
40%
A soil has a CEC of 20. You calculated individual ions as CEC-Ca = 4, CEC-Mg = 1, CEC-K = 3, CEC-Na = 0.5, CEC-Al = 5, CEC-H = 6.5. What is the percent base saturation?
42.5%
Liming material that is falls through an 8-mesh screen, but is captured on a 60-mesh screen should be assumed to be _______% effective.
50
The ideal pH for most crops is between _____________ and _____________.
6.0 and 6.8
For a soil to be concidered a sand, the soil must be composed of at least ____ sand
70%
Permanent charges account for ___________ % of the CEC in smectite.
90
Crumb aggregates would typically be found in the ___________ horizon.
A
Topsoil is generally equivalent to which soil horizon
A
Which horizon is most likely to have high concentrations of organic matter
A
A soil with a bulk density of 0.35 g/cm3 is most likely what type of soil?
A peat soil
Which of the following soil horizons was likely found beneath a grassland
A1, A2, Bt, Bt2, C
Alkalinity in a soil forms as a result of ____________________.
Accumulation of carbonates
A soil with a pH of 6.5 would be considered _______________.
Acidic
The addition of H2SO4 to pure water will make the water _____________.
Acidic
A tree falling and slowly decomposing in the forest is an example of which of the 4 basic processes of soil formation?
Additions
A tree that dies due to prolonged flooding is an example of a soil failing to provide ___________.
Air
Soil at the hygroscopic coefficient is also referred to as _________ .
Air-dry
Soils with a pH of 5.0 can have potentially toxic levels of ________ and ____________.
Al and Mn
A soil with a pH of 8.5 would be considered ________________.
Alkaline
A soil is said to be at Field Capacity when ______________________.
All gravitational water has been removed
Organisms that will affect the soil can best be described as
All of the above
Parent materials deposited by water are termed:
All of the above
The development of micropores is generally related to:
All of the above
In pure water, the pH is 7.0 because the _______ and _________ are balanced.
Anions, Cations
In which of the following horizons has the process of illuviation most likely occurred?
B horizon
Silicate clay accumulation is most common in the ____.
B horizon
A soil horizon has the following horizons: Oi, A1, E, Btg, BC, C. Which horizon has the highest amount of illuviated clays?
Btg
A soil horizon has the following horizons: Oi, A1, E, Btg, BC, C. Which is the least affected by pedogenic processes?
C
In soils of which great group would you most likely find wide surface cracks during periods of dry weather?
Calciusterts
Organic matter is ultimately converted into:
Carbon dioxide
Soils high in silt will form a _____ when squeezed
Cast
The oxygen end of a water molecule is attracted to ___________.
Cations (like Na and Ca)
A sticky, putty-like feel indicates a high percentage of what soil separate?
Clay
Colloidal properties are exhibited by ________ soil particles.
Clay
Which soil textural class has the lowest bulk density?
Clay
A soil horizon has the following horizins: Oi, A1, E Btg1, Bc, C. Which layer has had the most material lost to leaching?
E
Which horizon is most likely to have high concentrations of quartz?
E
A horizon with characteristics of both an underlying A horizon and an underlying E horizon
EA
In which of the following soil orders would recent alluvium most likely be a common parent material?
Entisols
Micronutrients are used primarily in _________________.
Enzymatic reactions
A loam is a soil that _________ soil separates in equal proportions
Exhibits the properties of
A loam is a soil that ______________ soil separates in equal proportions.
Exhibits the properties of
Fertile soils along the Nile in ancient Egypt are correctly termed:
Floodplains
An Al-oxide clay that forms the tetrahedral sheet of our 2:1 crystalline silicate clays is ___________.
Gibbsite
In your soil, you notice an abundance of coarsely weathered materials with rounded edges. These materials were most likely from ____________ deposits.
Glacial
An example of an acid parent material is ______________.
Granite
Which of the following is a direct measure of soil moisture?
Gravimetric
In which of the following forms of soil water are pesticides, excess plant nutrients, and waste chemicals most apt to move through soils?
Gravitational
Percolation in a saturated soil is driven by:
Gravity
A color with a chroma of /1 would appear as ______
Gray
Biogeochemical weathering occurs most rapidly in the presence of:
Heat and water
Sands are used as a base for golf greens because ______________.
Higher infiltration and percolation rates prevent disease
Carbon dioxide levels in the soil are ___________ those of the atmosphere.
Higher than
The following chemical equation CaSO4 + 2H2O Þ CaSO4·2H2O is an example of:
Hydration
Kaolinite clays do not expand because of the ______ bonds that form between the tetrahedral and octahedral
Hydrogen
Which of the following soil temperature regimes would provide the warmest and least variable soil temperatures?
Hyperthermic
An example of an alkaline parent material is ______________.
Limestone
Based on your experience with the Interactive Triangle on Pedosphere.com, which soil will have the highest bulk density?
Loamy Sand
Using the textural triangle, a soil with 85% sand and 8% clay belongs to the _______ textural class.
Loamy Sand
Which of the soils below will likely have the lowest CEC?
Loamy Sand
Dull gray colors are characterized by ____________.
Low chromas
Soil _________pores do not hold water against the force of gravity.
Macro
Blocky aggregates develop in __________ soils.
Moist
Which of the following would most likely have permafrost? Justify your answer.
Mucky, Euic Typic Aquaturbel
Soil colors are described scientifically by ____________ color designations such as 10YR 3/4.
Munsell
A plant with stunted growth and yellow leaves is likely deficient in ________.
N
The 3 primary macronutrients include ______________.
N, P, K
The fertilizer Urea hydrates when it comes in contact with moisture in the soil
Nutrient elements
Organic matter accumulation is most pronounced in the ____.
O horizon
A tree is blown over in a storm. This is a failure of the soil to provide __________.
Physical support
Soils in the E horizon generally have _____________ aggregates.
Platy
An Ap horizon was most likely ____________ at some point during its formation.
Plowed
The ____________ of water contains for its cohesive properties.
Polarity
Acidity in a soil forms as a result of _________________.
Precipitation of carbonates
The herbicide Glyphosate becomes inactive when it comes in contact with the soil. This is an example of soil providing _____________.
Protection from toxins
The primary function of a soil is _______________.
Provide a medium for plant growth
A color with a value of 10/ would appear as _____________.
Pure White
Sand grains are generally made of the primary material
Quartz
Soils formed form parent materials weathered in place are termed.
Residuum
The reaction []H+ + Na+ <--> []Na+ + H+ is an example of the CEC principle.
Reversibility
Soils high in clay will form a ___________ when squeezed.
Ribbon
If you have a heavy soil with an infiltration rate of 0.25" per hour, what happens if precipitation or irrigation rates occur at 1.0" per hour?
Runoff and Erosion
A gritty feel indicates a high percentage of what soil separate?
Sand
Distinguish between the 3 soil particle sizes. Give their size range and how they feel to the touch.
Sand • Particles between 2.0 and 0.05 mm in diameter • Particles feel gritty when rubbed Silts • Particles between 0.05 and 0.002 mm in diameter • Particles feel smooth or silky when rubbed Clays • Particles <0.002 mm in diameter. • Particles feel sticky when wet
You have three soil particles measuring 1.5, 0.1, and 0.01 mm in diameter. These soil particles would be:
Sand, sand, silt
A loam that is more than 50% sand may belong to the textural class ________________.
Sandy Clay Loam
Which of the following is not a textural class name?
Sandy silt
A smooth, talc-like feel indicates a high percentage of what soil separate
Silt
The percentage of what soil components represent the minimum information necessary to determine the textural class of a soil?
Silt and Sand
A loam that is more than 30% clay may belong to the textural class ______
Silty Clay
Which of the soils below is likely to have the highest water holding capacity?
Silty Clay
Soils in the A horizon generally have _________ aggregates
Spheroidal
The primary function of a soil in engineering is _______________.
Support buildings and roads
You can improve the CEC of 2:1 silicate clay soils by ________________.
adding organic matter
Which of the following diagnostic horizons would likely not restrict root growth in soils?
albic
Which of the following describes a soil likely to contain a significant content of low activity clays?
an Ultisol in the Congo River basin in Africa
Which of the categories in the Soil Taxonomy system indicates properties that have implications for root growth as well as for the construction of building foundations?
family
What mineral is most resistant to weathering under humid temperate conditions
gibbsite
In sandy soils of coastal regions and sand based golf greens, the CEC arises almost entirely from __________.
humus
The reaction: mica + H2O º K+ + OH- + acid clay is an example of ________.
hydrolysis
Water becomes soil water immediately following
infiltration
The element most often involved in oxidation reactions as minerals weather is
iron
The negative charges associated with smectite clay minerals are due mostly to ____________.
isomorphous substitution of Mg for Al in the octahedral sheet
Soil is considered a dynamic natural medium because
it is constantly changing
Which of the following is not a characteristic of soil colloids?
low water holding capacity
Which of the following is not a secondary mineral?
microcline
The higher the CEC, the ____________ it takes to change soil pH.
more
Plants deficient in K are characterized by ___________________.
necrotic leaf margins
Alluvial fans are usually characterized by ______ soils.
sandy and gravelly
The map units on a detailed soil map in a county soil survey report are most likely to be labeled with names from which category of Soil Taxonomy?
series
If you were seeking a soil colloid with a high capacity to absorb cation pollutants, but should do so as the pH varied from 4.5 to 7.5, which of the following would you choose?
smectite
Soils rich in what type of clay would provide the most troublesome site on which to build a home?
smectite
Soils control the fate of water in the environment through ________, ___________, and limiting _____________.
storage, filtration, evaporation
Mechanical weathering processes results in
the disintegration of rocks due to differential expantion of minerals
Put simply, CEC refers to ____________________________.
the quantity of negative charges on the surfaces of clay and organic matter
Illite --> kaolinite --> iron/aluminum oxide represents a
weathering sequence
Describe the 5 functions of a soil in an ecosystem.
•Support the growth of higher plants •Control the fate of water •Function as nature's recycling system •Provide habitat for living organisms •Provide an engineering medium
