soil science final
In a given soil, the mineral horizon with the highest organic matter content is generally the ________ horizon.
A
"Subsoil" is generally equivalent to which soil horizon?
B
The parent materials for most coastal plain soils are residual in nature. T/F
False
Most of the water flowing in rivers passed through a soil profile or over soil surfaces before reaching the river. T/F
True
Organic deposits are common in areas where water ponds for extended periods of time. T/f
True
Soil air usually has a higher carbon dioxide content than the air in the atmosphere. T/F
True
The O horizons of a soil are dominantly organic horizons occurring above mineral horizons. T/F
True
In which of the following soil orders would you most likely find a melanic diagnostic horizon?
andisols
Which type of structure is typically found in sodium-rich sub-surface horizons?
columnar
Most, if not all, of the nutrient supply stored in a fertile soil is in forms readily available to plants. T/F
false
The B horizon is the zone where you would expect maximum elluviation.
false
A 1:250,000 soil survey covers a larger area with less detail than a 1:12,000 soil survey.
t
A 2:1 type silicate clay has one octahedral sheet sandwiched between two tetrahedral sheets
t
Active soil acidity is a measure of the H+ ion activity in the soil solution.
t
Conservation tillage has generally positive effects on soil physical properties.
t
For any soil, the bulk density is always lower than the particle density.
t
Fungal hyphae play an important role in stabilizing surface soil aggregates.
t
Humus has a higher cation exchange capacity at pH 8.0 than at pH 5.0.
t
Iron and aluminum hydrous oxides are characteristic of soils that are highly weathered chemically.
t
Microbial metabolism in the guts of termites and in waterlogged soils are two major sources of excess methane that is contributing to the global greenhouse effect.
t
Nitrogen fertilization is a significant cause of acidity in many cultivated soils.
t
Ridge-till systems show promise in the management of somewhat poorly drained soils of the Midwest.
t
Soil consistence changes with changes in soil water content.
t
Soil phosphorus is associated with eutrophication of lakes
t
Soil reaction indicates the degree of acidity or alkalinity in a soil.
t
Soil temperatures under an organic mulch will likely be lower than that of bare soils in the summer but higher than that of bare soils in the winter.
t
The T values are the maximum losses of soil by erosion that can be tolerated without a reduction in the soil's long term productivity.
t
The broadest category of classification in Soil Taxonomy specifies 12 soil orders.
t
The cation exchange capacity of a soil is determined primarily by the amount and kind of colloids in the soil and by the pH.
t
Plants require seventeen essential elements to complete their life cycle. Manganese is one of the essential elements considered a _____.
micronutrient
Which one soil condition is most instrumental in fostering the process of denitrification?
periods of excessive wetness
Which nutrient's plant availability is most closely governed by soil pH?
phosphorus
The process of exfoliation is an example of _____.
physical weathering
Select the one that doesn't go with the other three.
plasticity
Soil organic matter consists of ________.
polymerized, non-identifiable molecules b. dead tissues and wastes c. identifiable biomolecules d. living organisms and cells
For any soil, the bulk density is always higher than the particle density.
pore size distribution
What feature would best tell a soil's "age"?
profile horizonation
The lower the cation exchange capacity of a soil, the lower is its pH buffer capacity.
t
The mineral particles in soil consist of sand, silt, and clay.
t
The soil erodibility factor in the Universal soil-loss equation (USLE) relates primarily to the soil's infiltration capacity and structural stability.
t
_____ is not considered one of the five major factors influencing soil formation.
translocations
An aquic soil moisture regime connotes a higher degree of soil moisture saturation than an ustic one.
true
Eluviation of clay, iron, and other materials is the principal process responsible for the formation of an E horizon. t/f
true
Organic matter distribution in the soil is a significant criterion for differentiating epipedons. T/f
true
Plants can be grown without any soil.
true
Practices that tend to increase the amount of organic matter in soils would be expected to reduce the global greenhouse effect. T/F
true
Sapric and fibric are terms used to describe peat parent materials. T/F
true
Secondary minerals are recrystallized products of the chemical breakdown and/or alteration of primary minerals. T/F
true
The A horizons are more apt to be cultivated than the E horizons. t/f
true
The mineral particles in soil consist of sand, silt, and clay. T/F
true
You would be more apt to find an Gelisol in Alaska than in Iowa. t/f
true
Sandstones are good examples of igneous rocks. T/f
False
n acid soils, the principal chemical form of phosphorus available for plant uptake is _____.
H2PO4-
Vertisols are characterized by high contents of swelling-type silicate clays.
t
Soils in which of the following soil suborders would most likely have a prominent E horizon under the A horizon?
udalfs
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?
uldisols
Igneous rocks can best be characterized as _______
. rocks formed when molten magma solidifies Correct
A soil with a silt loam textural class might contain ___.
10%
highly weathered soil in a tropical rain forest can contain significant amounts of clay. Which of the following is it most likely to be?
1:1 clay c. Aluminum Oxide d. Iron Oxide
The sand fraction is represented by particles in which size range?
2.0 and 0.05 mm
In a load of 10 cubic meters of topsoil, approximately how cubic meters of the volume would be solid material?
5
In what range of soil pH is phosphorus generally most available to plants?
5.5-7.0
n what range of soil pH is phosphorus generally most available to plants?
5.5-7.0
In a typical mineral soil in optimal condition for plant growth, approximately what percentage of the pore space would be filled with water and what percentage filled with air?
50% water and 50% air
Which of the following pH values represents a neutral condition?
7.0
"Topsoil" is generally equivalent to which soil horizon?
A
Which of the following soil horizon sequences would be associated with the least mature soil profile?
A-C-R
Which of the following soil horizon sequences would be associated with the most mature soil profile?
A-E-Bt-C
For a 2:1 type clay mineral, one of the sources of negative charge is the result of isomorphous substitution as illustrated by _____.
Al replacement of Si in the tetrahedral layer
Select the appropriate horizon: Strong gleying indicating iron has been reduced and removed during soil formation.
Bg
Select the appropriate horizon designation: Illuvial accumulation of organic matter.
Bh
Loss of P to groundwater is likely to be most significant for which type of soil?
CULTIVATED ORGANIC SOILS
The Edneyville Series is a Coarse-loamy, Mixed Active Mesic, Typic Dystrudept. What is the Family?
Coarse-loamy, Mixed Active Mesic
Which of the following has a Bw horizon
Coarse-loamy, Siliceous, Active, Acid, Thermic Cumulic Humaquepts
Which of the following is (are) essential plant nutrients?
Cu
If you wanted to find a soil where physical weathering dominated over chemical breakdown you would be most apt to find it in ________.
Desert region of Arizona
Examples of genetic horizons include kandic, spodic, ochric, mollic and oxic.
F
A soil developed in transported parent materials will likely have properties related to the properties of the rock below the C horizon. T/F
False
A, B, C, and E horizons can be found in any true soil. T/F
False
Although subsoil is more difficult to obtain, it is generally equally as good as topsoil for landscaping purposes. T/F
False
For any soil in which the B horizon is present, the C horizon is the parent material for that B horizon. T/F
False
Hydroponics will likely be a key element in enabling the world to feed and clothe its increasing human population in the next few decades. T/F
False
Soils developed in wind-blown parent materials such as loess are generally of little agricultural value. T/F
False
Subsoil is typically equivalent to the O horizon. T/F
False
The dark brown and black humus found in many soils does not mix well with clay minerals so there is very little contact between these two soil components. T/F
False
Which formula best describes bulk density?
Oven Dry Weight (g) ÷ Volume of Soil (cm3)
The particle density of a soil can best be described by:
Oven dry weight divided by volume of just the soil particles
Which of the following is considered to be a plant macronutrient?
P, S, N
In many soil profiles, the subsoil is high in clay, but is also quite permeable to percolating water. Why?
Prismatic structure may be well developed.
_____ is not one of the textural classes?
SANDY SILT
Rank the following soil components in order of cation exchange capacity, lowest to highest:
Sand -> Clay -> Organic Matter
Soils in this order are commonly sandy in texture, quite acidic and develop primarily under coniferous trees in cool to cold climates.
Spodosols
Which of the following categories of Soil Taxonomy provides the greatest specificity of soil properties?
Subgroup
the nomenclature of Soil Taxonomy is characterized by all of the following statements?
The subgroup name also tells you the great group, suborder, and order names. c. The names are based on measurable properties and not on presumed modes of genesis. d. Soil names (except for series level) identifies major soil characteristics. e. The names of the orders all end with the letters sols.
If supplied with a suitable nutrient solution and a mechanism for physical support, plants can grow normally without any soil at all. T/F
True
In humid regions most rainwater that soaks into the soil and is not used by plants eventually flows into rivers and streams. T/F
True
Lacustrine parent materials have been subject to weathering for shorter periods of time than residual parent materials nearby. t/f
True
Minerals that contact iron are more resistant to chemical breakdown than minerals that contain CaCO3. T/F
True
Residual parent materials have generally been subjected to weathering for a longer period of time than have lacustrine or alluvial parent materials. T/F
True
Which of the following best characterizes the field capacity of a soil?
Water content of a soil about 24 hours after saturating rains
Of the horizons listed below, the one with the highest organic matter content is generally the _____ horizon
a
A soil pedon is ________
a three-dimensional unit that embodies the primary characteristics of an individual soil
A pure clay crystal of kaolinite contains one octahedral layer and one tetrahedral layer. Which of these descriptions best describes the individual octahedrons that form the octahedral layer:
a. 1 aluminum and 6 oxygens
Which of the following statements is true concerning a. cohesion and adhesion
a. Adhesion is the force that initiates capillary rise in micropores.
Glacial till is a term used to describe parent materials that ________.
a. contain a heterogeneous mixture of mineral debris dropped by receding glaciers.
The water in the soil typically differs from pure water because the soil water ________.
a. contains mineral nutrients b. contains organic compounds c. is restrained in its flow by attraction to particle surfaces
Urban development of land that was previously natural vegetation or farm lan usually greatly ________ soil infiltration capacity and therefore greatly increases ________
a. decreases; stream bank erosion.
Which of the following is (are) major sources of the carbon dioxide now being added to the atmosphere in excess of the amount taken out by plants?
a. destruction of natural forests b. burning of fossil fuels c. loss of soil organic matter
Argillic horizons are characterized by ________.
accumulation of silicate clays
Soils having experienced a high degree of leaching would probably also be _____
acidic
Which cation would you expect to be mostly tightly held in a soil at pH 4.5?
al 3+
. Which cation would be held most tightly in a soil at pH 4.5?
al+3
At saturation, water can be found in _____
all pores
____ is a parent material that would show evidence of sorting actions due to water?
alluvium
A compound containing _____ when applied to soil, will usually lower soil pH.
aluminium
Which ion hydrolyzes water molecules, resulting in the release of H+ thereby acidifying the soil?
aluminum
Exchangeable soil acidity is a measure of the _____.
aluminum and hydrogen ions attracted towards the charge of the clay and humus surfaces
24. On very acid soils, a chemical problem that can reduce plant growth is _____
aluminum toxixity
The presence of rocks such as shale and sandstone indicate the existence of ________.
ancient seas
Which of the following human actions is most apt to result in a long term decrease in soil pH?
application of NH4- containing fertilizers b. emission of gases from automobiles c. Application of unlimed sewage sludge d. Application of farm manure
Which of these diagnostic horizons is not an epipedon?
argillic
Which of these orders would have soil properties dominated by physical weathering processes?
aridisol
The osmotic potential would likely be lowest in soils of which of the following orders?
aridisols
Soil scientists generally map the soils in a landscape by sampling the soil in ________.
auger holes made mostly near expected soil boundaries
In most B horizons one of the dominant processes of soil formation has been eluviation.
b
Clay accumulation is most common in the _____.
b horizon
Silicate clay accumulation is most common in the ________.
b horizon
illuviation
b horizon
Many members of which group of soil microorganisms are anaerobic heterotrophs?
bacteria
Parent material is generally equivalent to which soil horizon?
c
Which suborder has the lowest soil moisture levels?
calcid
Phosphorus availability is very low in most strongly basic soils because of its reactions with _____.
calcium
Humus is an important soil colloid. It differs from 2:1 type minerals in all but one of the following characteristics:
capable of absorbing cations
The reaction: mica + H2O → K+ + OH- + acid clay is an example of ________
chemical
Which of the following essential micronutrients is d. an anion, subject to leaching losses?
chlorine
If a dry soil high in certain types of ________ is moistened, it is likely to swell up with enough force to crack pavements and building foundations.
clay
Secondary minerals are most prominent in the ________ fraction of soils.
clay
These particles are plate like in shape.
clay
in texture by feel methods, this component accounts for longer ribbon formation.
clay
Yellow colors in subsurface horizons are caused by _____ in the soil.
clay iron oxides
Events that compact soil would most likely affect all these soil properties, except _____.
clay surface area
Physical weathering of parent materials is dominate in which below listed climate?
cold and dry
The sulfur dioxide in the atmosphere ________.
comes from fires such as fossil fuel burning, volcanoes and forest fires b. can be an important source of sulfur nutrition for plants c. is a major contributor to "acid rain"
Which of the following processes are most apt to encourage good soil aeration?
creation of macropores
In soils of which great group would you most likely find wide surface cracks during periods of dry weather?
d. Calciusterts
Soil detritivores feed principally on ________.
dead tissues
Detritus consists of ________.
dead tissues and wates
As pore space volume increases, soil bulk density
decreases
Which horizon of a mature soil profile would have the lowest clay content?
e
During the growing season of any plant (forest
evaporation and transpiration
A 2:1 type silicate clay has one tetrahedral sheet sandwiched between two octahedral sheets.
f
A soil with a high organic matter content will have a relatively higher bulk density than a mineral soil.
f
Alluvium typically results in mature soils with defined A, E, B, and C horizons
f
Although slow release fertilizers take longer to have an effect, they are more economical than regular nitrogen fertilizers and so are favored by foresters and farmers.
f
Although the total soil water content of a clay soil is about the same as a nearby well structured silt loam, the clay will likely provide more available water to plants because of its higher volume of small pores.
f
Ammonia volatilization is a process by which much needed nitrogen is added to the pool of plant- available nitrogen in soils.
f
Ammonification, the first step in mineralization, is a major source of soil acidity
f
As decomposition of added organic material proceeds, the C/N ratio in the remaining undecomposed material steadily increases.
f
Coarse-textured soils have the highest water holding capacity of any soil at field capacity.
f
For agricultural use in a given region, a soil with an ochric epipedon could generally be expected to be more productive than one with a mollic epipedon. t/f
f
For any soil, the bulk density is always higher than the particle density.
f
For most soils, plowing every year improves soil tilth in the long run.
f
Humus has a much higher cation adsorption capacity at pH 5.5 than at pH 8.0.
f
Humus has a much lower cation exchange capacity than iron oxides.
f
In most temperate, humid regions, the period of greatest potential for nitrate leaching is during the summer when nitrogen fertilizer is applied to crops.
f
Mycorrhizae do not normally kill their host plants, but merely reduce the efficiency of the plant root system.
f
Polysaccharides produced by soil microbes and similar synthetic polymers applied to soils are largely responsible for the crusts that form when rain follows tillage.
f
Relative to core-aeration, spike-aeration is the preferred method of improving gaseous exchange between the soil and the atmosphere.
f
Roots of most plants have difficulty growing through soil if the bulk density is greater than 1.0 Mg/m3.
f
Slope length is generally of greater significance in determining erosion rate than is steepness of slope.
f
The categories of Soil Taxonomy can be listed from the broadest (first) and most specific (last) as: order, suborder, great group, subgroup, series, famil
f
The depth of a soil profile is a function of climate. Cold dry conditions result in deep well developed soils whereas wet and warm conditions result in shallow immature soils.
f
The tenacity with which water is held in soils is directly related to the soil moisture content, the higher the moisture level the greater the attraction of the water to the soil.
f
The tenacity with which water is held in soils is directly related to the soil water content. The higher the soil water content, the greater the attraction of the water to the soil.
f
The total global soil lost through erosion is generally greater from gully erosion than from sheet erosion.
f
The water potential in the atmosphere is generally considered higher than that in the soil.
f
Weathering of rocks usually is most intense in the center of a rock fragment, and gradually decreases toward the outside.
f
he matrix potential is related to the presence of salts and other solutes in the soil.
f
he plasticity index is used to determine soil texture.
f
Spodosols are generally less acidic and less sandy than are Alfisols.
f`
A pedon is a three-dimensional field unit occupying about 10,000 square meters (1 hectare) of land area.
false
Andisols form in the bottoms of old glacial lakes. t/f
false
For any soil in which it is present, the B horizon is the parent material.
false
Soil, like concrete and steel, is a standard construction material. Its properties are well characterized and predictable so that standard building foundation designs can be used uniformly at all building sites of a given topography. t/F
false
Soils classified as Inceptisols have the least well developed profiles of those in any order in the Soil Taxonomy system.
false
The hydrogen end of a water molecule is attracted to positively charged cations such as Na+ and Ca2+.
false
The percent of total pore space in a soil can be calculated if only the particle density and the organic matter content are known.
false
The topmost horizon in most cool-humid forest soils is the A horizon. t/f
false
Where organic matter constitutes only 1 or 2 percent of the soil by weight, it has only negligible influence on soil properties. T/F
false
You would be more apt to find a Gelisol in Iowa than in Alaska.
false
oils in the Oxisols order are deeply weathered and have deep subsurface horizons of calcium oxide.
false
Because soil development is just beginning in Entisols, these soils are generally less variable in properties than are those in the Andisol or Ultisol orders.
fasle
homeowner in New Mexico attempted to grow azaleas in a well drained soil (pH 7.5) but the plants were stunted and the leaves were yellow. What is the most likely cause of this constraint
fe deficentcy
You are working with a soil colloid known to have a reasonably high potassium level, a cation exchange capacity of about 20 cmolc/kg of clay and little tendency to swell when wetted. Which of the following is it most apt to be the dominant clay mineral in this soil?
fine grained mica
Select the appropriate soil order: Organic soils that are frozen.
gelisols, molisols, spodosols,
Which mineral is most resistant to weathering under humid temperate conditions?
gibbsite
Which of the following is a secondary mineral?
gibbsite c. silicate clay d. calcite
16. Once an acid soil is limed and the pH increases to near neutral, the pH can be expected to _____.
gradually become more acidic
A structure type common to surface soils that typically has an ideal pore size distribution for plants is _____.
granular
Which type of soil structure is typically found in surface soil (A horizons)?
granular
The _____ method of estimating soil water levels gives a direct measurement of water content.
gravimetric determination
Total soil water potential is a function of _____.
gravitational potential b. osmotic potential c. matric potential
Pesticides and excess plant nutrients most likely to leach from the bottom of the soil profile by moving in the _____ water.
gravitational.
Compared to silt, clay-sized soil particles are characterized by ________.
greater attraction for water
In acid soils the principal chemical form of phosphorus available for plant uptake is ________.
h2p04-
he total phosphorus lost from various watersheds is most closely correlated with _____.
high soil erosion
Water movement in a soil would be from a zone of __.
higher and lower water potential
Soils high in organic matter commonly hold more plant-available water than comparable soils with lower organic matter levels. This is most likely due to what characteristics of the high O.M. soils?
higher field capacity
Investigating the soils of northern Canada on summer, you dig a soil pit easily though fairly uniform peat material until, at 75 cm deep, your shovel hits a layer that is frozen solid. Into which type of soil are you most likely digging?
histel
Which of these diagnostic horizons has the most organic matter?
histic
Soils with thick horizons consisting mainly (> 30% by weight) of organic matter and that form in topographic depressions or low-lying places usually belong to the order ________.
histosols
Chemical weathering of parent materials is dominate in which below listed climate?
hot and moist
Active soil acidity is a measure of the _____.
hydrogen ion activity in the soil solution
One method for determining the percent sand, silt and clay is called the _____ method.
hydrometer
granite
igneous rock
If the average transpiration (T) loss from leaf surfaces in a particular watershed is 10 mm/day, you expect the evaporation (E) from the soil surface to be _____.
impossible to calculate from the data given
A cover crop is usually grown for the purpose of ________.
improving soil physical conditions, and saving and recycling nutrients
The Edneyville Series is a Coarse-loamy, Mixed Active Mesic, Typic Dystrudept. What is the Order?
inceptisol
Tillage when the soil is too wet will destroy soil structure, which in turn _____
increase bulk density
Increasing the organic matter content of a soil is likely to ________.
increase the soil's water holding capacity
he nitrification reaction is: NH4+ +2O2 →2H+ +NO3- +H2O this reaction........soil acidity
increases
Capillarity in soils ________.
involves both adhesion and cohesion
Phosphorus availability is very low in most strongly acid soils because of its reactions with _____.
iron
The element most often involved in oxidation and reduction reactions as soils weather is
iron
Poor plant growth in a well-drained irrigated soil in an arid region (pH=8.0) is most likely due to
iron deficiency
Brown and red colors in subsurface horizons are caused by ________ in the soil.
iron oxides
The negative charges associated with smectite clay crystals are due mostly to ________.
isomorphous substitution of Mg for Al in the octahedral sheet Correct
Perforation placement is usually used to fertilize ________.
landscape trees
Using a textural triangle chart, it can be determined that a soil with 45% sand and 20% clay belongs to the ________ textural class.
loam
Many of the soils in the Midwest region of the United States contain fine deposits of windblown materials, a parent material known as _____.
loess
_____ is not considered one of the four general processes of soil genesis.
loessification
Select the correct order of increasing bulk density, from lowest to highest.
loose clay, loose sand, compact sand, compact clay
Dull gray colors are characterized by ________.
low chromas
A gray color in soils furnishes evidence that the soil has _____.
low oxygen levels
Residual parent materials are best described as ________
materials formed by weathering of rocks and minerals in place.
Which of the following practices is(are) useful in stabilizing surface soil structure?
minimizing tillage b. growing grass sod c. use of organic mulches d. use of cover crops
If you were seeking a soil colloid with a high capacity to adsorb cationic pollutants, but also with a consistent capacity to do so even as the pH varied form 4.0 to 7.5, which of the following would you choose?
montmorillonite
n soil science, color is described by _____ color designations such as 10YR3/4.
munssel
The very high pH levels found in some arid region soils are most likely due to high levels of exchangeable ________.
na+
Which process in the nitrogen cycle converts
nitification
Which process describes the conversion of nitrogen from one plant available form into another plant available form?
nitirificaiton
A soil with 60% sand will include _____.
no way to determine
In which of the following epipedons is the organic matter level generally lowest?
ochric
Which of these diagnostic horizons is an epipedon?
ochric
Deposition and/or mineralization of organic materials in soil is not a significant contributor of the _____ used by plants?
oxygen
Normal activities in soil causes ________ to become diminished in soil air and _______ to increase.
oxygen, carbon dioxide
A subordinate designation of _____ indicates a soil horizon with evidence of disturbance by agricultural activities.
p
A soil with a bulk density equal to 0.35 Mg/m3 is most likely what type of soil?
peat soil
Plants require seventeen essential elements to complete their life cycle. Potassium is one of the essential elements considered a _____.
primary marconutrient
The lithosphere is made up of ________.
rock
Igneous rocks can best be characterized as _____.
rocks formed when molten magma solidifies
Soil scientists from which country first conceived the idea that soils were natural bodies?
russia
Which of the following is not a textural class name?
sandy silt
Plants require seventeen essential elements to complete their life cycle. Magnesium is one of the essential elements considered a _____.
secondary macronutient
Which of the following categories of Soil Taxonomy provides the greatest specificity of soil properties?
series
e map units on a detailed soil map on Web Soil Survey are most likely to be labeled with names from which category of Soil Taxonomy?
series
In texture by feel methods, this constituent is described as feeling smooth or flourlike.
silt
The percentages of which soil components represent the minimum information necessary in order to determine the textural class of a soil?
silt and sand
Which cation does not promote flocculation in the soil?
sodium
Which cation promotes dispersion in the soil?
sodium
the P factor in the Universal soil-loss equation is concerned with all but one of the following:
soil erodibility
Wind erosion is generally not affected by ________
soil ph
Most of the different nutrients essential for growth are supplied to plants directly from the ________.
soil solution
Soils in this order are commonly sandy in texture, quite acidic and characteristically have a Bh horizon.
spodosols
Fungal hyphae have an important influence on soil structure because they ________.
stabilize macro aggregates
Plants require seventeen essential elements to complete their life cycle. Hydrogen is one of the essential elements considered a _____.
structural component
Most (usually 80% or more) of soil potassium and calcium can be found in the form of
structural components of minerals Correct
Udept is an example of a soil _____.
suborder
electronegative charge on 2:1 type silicate clays is due primarily to _____.
substitution of one metallic atom for another in the crystal structure of
The principal form of sulfur taken up by plants is ________
sulfate
Chemical weathering is accelerated by water, oxygen, and organic acids moving down through the regolith
t
Due to differences in soil drainage, proper timing of tillage is generally more difficult for a clayey than for a sandy soil.
t
Elemental sulfur can be used to increase soil acidity and to reduce alkalinity.
t
Forests would typically have less organic accumulation than grasslands.
t
Histosols generally have higher organic matter contents than Mollisols.
t
In a soil with very low cation exchange capacity, the most efficient approach to using fertilizer would be to apply frequent small doses rather than a single large dose.
t
In a soil, oxidation and reduction occurs as chemical elements and compounds accept or donate electrons.
t
In the United States, losses of soil due to wind and water erosion decreased by nearly 40% between 1982 and 2003.
t
Most nitrogen leaching to groundwater is in the form of nitrate.
t
Of all the groups of soil organisms, bacteria have the most diverse metabolic capabilities.
t
Sand is composed mostly of primary minerals.
t
Soil colloids are too small to be seen with an ordinary light microscope
t
The cation exchange capacity of humus increases if pH increases.
t
The drainage class of a soil (the degree to which the soil becomes water-saturated during the year) can be judged by the presence and location of gley in the soil profile.
t
The drainage class of a soil (the degree to which the soil becomes water-saturated during the year) can be judged by the presence and location of gray colors in the soil profile.
t
The leaf area index significantly affects the solar radiation reaching the soil surface.
t
The name of a subgroup indicates the order, suborder, and great group of which it is a membe
t
The oxisols are the most weathered soil order.
t
The residual acidity in soil is much larger than active
t
The two most significant characteristics of the classification system used in the United States are a unique system of terminology and focus on measurable soil properties as a primary basis for the classification.
t
Exfoliation is caused by changes in ________.
temperature
The amount of different sizes of mineral particles in a soil defines the soil ________.
texture
Tillage has the least influence on _____.
texture
tillage has the least influence
texture
What property of clays does isomorphism affect?
the cation exchange capacity
A soil profile consists of ________.
the set of layers seen in a vertical cross section of a soil
A productive, heterogeneous deposit associated with glacial activity forms a parent material known as ____.
till
vWeathering of primary minerals to form secondary minerals is an example of what type of soil-forming process?
transformations
A soil developed in residual parent materials will likely have properties related to the properties of the rock below the C horizon. t/f
true
Compared to conventional tillage systems, most conservation tillage systems rely more heavily on herbicides to control weeds.
true
You would expect the cation exchange capacities of Ultisols to be lower than those of Aridisols if the soil textures are about the same.
true
A soil horizon sequence of A-E-Bt-C-R would be characteristic of which soil order?
ultisol
Select the appropriate soil order: Highly weathered soils developed under forests in the humid areas. A true B horizon is present. The subsoil has a base saturation below 35%.
ultisols
Soil occupies the ________ part of the regolith
upper
ou 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
If you were looking for a soil with high cation exchange capacity and were not concerned with the soils physical properties, which of the following would most likely fit your needs?
vertisol
Biotite → intermediary secondary mineral → iron oxide" represents a
weathering sequence
The E horizon is _____.
zone of maximum eluviation
