soils exam Final (cox)
At what Ph range does Al^3+ start becoming available to affect soil processes
5.2-5.5
In 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 with air
50% water and 50% Air
3 mole of Al^3+ contains how many moles of positive charge?
9
"Topsoil" is generally equivalent to which soil horizon
A
In a given soil, the mineral horizon whith highest organic matter content is generally the ______ horizon
A
Which of the following are true?
A mature soil does not need to have all of there mater horizons to be considered as oil.
Two soil samples A and B at different soil moisture levels are placed in contact with each other. Water will more likely move from soil A to soil B if their water potentials, expressed In Kpa are
A=+;B=-5
The B horizon can be high in
All of the Above
Living organisms can affect the soil profile through
All of the above.
The water in the soil typically differs from pure water because the soil water:
All of these
"subsoil" is generally equivalent to which soil horizon
B
In which of the following horizons has the process of illation most likely occurred
B horizon
silicate clay accumulation is most common in the
B horizon
Organic Matter additions to a soil can decrease
Db
which of the following irrigation systems produces the most biomass per unit of water applied ?
Drip irrigation
Mississippi has glacial parent material in the form of
Eolian loess
epipedons are diagnostic subsurface horizons that are one of the primary means of classifying soils in the United States
False
Soil A has a profile with a lot of yellow and red colors while soil B has a predominately gray profile. Of the two soils, Soil A is more apt to be characterized by an abundance of
Fe^3 IONS
compared to silt, clay sized soil particles are characterized by:
Greater attraction for water
Which of the following statements is correct?
LAcutrine parent material have been subject to weathering for shorter periods of time than residual parent materials nearby.
you find that the CEC of a sandy loam soil at PH 5.0 is 8cmpl/ckg and at PH *.2 it is 14cmol./kg. What is the most likely reason for this difference
Loss of H+ from carboxyl and phenolic groups in the oxides and organic matter
Dull gray colors are characterized by
Low chromes
water storage in the soil is due to
Matric potential
An a horizon with a sharp, distant boundary at about 6 inches due to cultivation would most likely have. which subordinate distinction
P
Two problems associated with this particular issue are poor seedling emergence rates and high runoff rates. what is the problem?
Soil crusting
Which of the following disintegration (physical breakdown) processes has the largest effects on rocks
Temperature
mechanical weathering processes results in:
The disintegration of rocks due to differential expansion of minerals.
The swelling/shrinking tendency of some silicate clay minerals is due primarily to_____.
The movement of water molecules in and out of the interlayers of the crystal.
You are consulting a farmer about there plans for the next few years. You have web soil survey open and notice that one of the fields has a Bg horizon 12" depth with a prodominelty gray background. from this information, you conclude which of the following
The soil is poorly drained the crops to be grown should be chosen carefully.
We must use our soils wisely and protect them because
They are reuseable,but not renewable recourse
The four soil formations process are
Translocation,transformation, addtitions and losses
Organic matter distribution in the profile is significant criterion for differentiating eppipdeons
True
The broadest category of classification in soil taxonomy specifies 12 soil orders, 11 of which are for mineral soils.
True
The mineral particles in the soil consist of sand, silt,and clay
True
evaporation from the soil surface (e) is determined to a large degree by soil surface wetness
True
A subsoil that has both a "g" and a "t" subordinate distinction (btg) can be expected to have
a clay accumulation and grey colors
soil quality is a term used to describe the soils
ability to carry out ecological functions
Argillic horizons are characterized by
accumulation of silicate clays
when measuring Ph with a PH meter, which pool of soil acicdiy are we measuring.
active
An important part of the definition of soil is that it is
all of the above
Which of the following will decrease the evaporation (E) from the soil surface
all of the above
which of the following practices is (are) useful in stabilizing the surface soil structure
all of the answers
colluvial parent material
along the slides slope and toe slope of a landscape
The presence of rocks such as shale and sandstone indicate the existence of
ancient seas
soil structure describes the____ of particles in a soil
arrangment
surface ditches are an effective way to remove large volumes of water
before it enters the soil
Practices that decrease organic matter and increase tillage can be expected to most significantly increase the _____ in the soil
bulk density
in soils of which great group would you most likely find wide surface cracks during periods of dry weather
calciusterts
Humus is an important soil colloid. It is like 2:1 type minerals in which one of the following characteristics
capable of adsorbing cation
secondary minerals are most important in the _______ fraction of soils
clay
secondary minerals are most prominent in the ______ fraction of soils
clay
Decreasing the organic matter content of a soil is likely to
decreases the soils structure . (disperse in the soil aggregates)
If you wanted to find a soil where physical weathering is dominated over chemical breakdown you would be most apt to find it in
desert region of Arizona
erosion process consist of three steps: Detachment,transport, and deposition. to control water erosion, we must devise methods to stop what?
detactchment of the silt fraction from the soil aggregates
soil crusting is due to aggregate
dispersion
A watermelon grower asked you for your recommendation on an irrigation method. Based on your experience which of the following methods would you recommend. (watermelons don't like wet soils and are a high value crop)
drip irrigation
which of the following is not a characteristic of most soil colloids
electropositive charges
A tetrahedral sheet is characterized by a plane of aluminum atoms surrounded by oxygen and hydroxyl groups.
false
A,B<c and E horizons can be found in any true soil.
false
Although subsoil is more difficult to obtain, it generally equals as good as topsoil for landscaping purposes
false
Except for some kinds of foods, modern industry has made human dependence on soils a thing of the past
false
The categories of soil taxonomy can be listed from the broadest (first) and most specific (last) as : order, suborder,greatgroup,subgroup, series family.
false
isomorphic substitution involves the substitution of a tetrahedral sheet for an octahedral sheet
false
polsaccharides produced by soil microbes and similar synthetic polymers applied to soils are largely responsible for the crust that forms when rain follows tillage
false
sandstones are good examples of metamorphic rocks
false
soil, like concrete and steel is a standard conturcution 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
false
subsoil is typically equivalent to the o horizon
false
while 2:1 type clays have significant internal surfaces, their external surfaces are generally much more extensive.
false
soils classified as inceptisols have the least well developed profiles of those in any order in the taxonomy system.
false.
which of the following categories of soil Taxonomy provides the greatest specificity of soil properties
family
some cations are important in rememditating soil crusting problems because they
help to flocculate the soil colloids
soil derived from eolian parent materials ten to be
highly erodible
The layers of contrasting material found when one digs a hole in the ground are called
horizons
In a soil at PH 5.0 most of the inorganic P is likely ti be in the form of
hydrous iron and aluminum phosphates
Muscovite mica is an example of a
igneous rock
Increaing the organic matter content of a soil is likely to
increase the soils water holding capacity
capillary in soils
involves both adhesion and cohesion
The element most often involved in oxidation reactions as minerals weather is
iron
The matric potential of soil water
is not influenced by the force of gravity.
The negative charges associated with vermiculite clay crystals are do mostly to
isomorphic substitution of Mg for Al in the octahedral sheets
The electronegative charge on 2:1 type silicate clays is due primarily
isomorphic substitution of one metallic atom for another in the crystal structure of the clay.
Why is AL^3 considers to be an acid cation
it hydrolyzes water and release H+ into the soil solution
As the clay content and /or the organic matter content increases in a. soil. What happens to the buffering ability of the soil.
it increases
subsurface land drainage is beneficial because
it increases the depth of root penetration in the soil.
Given the family: Fine -sandy, smectic mesic Aquaic Haplaudalf what do you know about this soil
its likely formed under a forest.
An ultisol can look like a mollisol or alfisol but it is different in that it has a
low base saturation
you are working with a soil colloid known to have a cation exchange capacity of about 100 cool/c Kg of clay and a high tendency to swell when wetted. which of the following is it most apt to be the dominant clay mineral in this soil?
monmorillinite
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 Ph varied form 4.0 to 7.5 which of the following would choose.
montmorillonite
what happens to perminate charge as the PH of the soil increases
nothing
organic matter accumulation is most pronounced in the
o horizon
Additons to the soil primarily affect the soil profile through
organic matter
which of the following is not a secondary mineral?
plagioclase feldspar
of the various types of drain systems open sitch system re most practical and economical for use on _____.
poorly drained soils with sandy profiles.
septic systems are designed to _____ household waste.
remove and treat
how does the amount of lime needed to neutralize the residual acidity in a clay loam soil compare to that needed to neutralize the active acidity in that soil.
residual requires a lot more
Ignenous rocks can be best characterized as
rocks formed when molten magma solidifies
In the soil-plant-Air continuum, once the water impacts the soil, it can either infiltrate into the profile or
runoff
A soil with a gritty feeling likely has a high percentage of which soil separate
sand
which of the following is not a textural class name?
sandy silt
As you move away from a river or a stream the soils tend to change from_____ in texture
sandy to sility to clayey
The map unites on a detailed soil map in a county soil survey report (same as Web soil survey) are most likely to be tabled with names from t=which category of soil taxonomy
series
using the Feel method, a soil creates a medium ribbon when pinched between the thumb and a forefinger. The ribbon is particularly smooth. What is the most likely soil texture
silty clay loam
A septic system needs soil to allow the waste water to move ____ enough to filter impurities
slowly
soils rich in which type of clay would not provide the best site on which to build a home.
smectite
The hydrologic cycle is the cycling of water from the atmosphere to ___. and then from the soil to either surface water or groundwater , and then to the oceans and back to the atmosphere
soil
The expression,P-ET-DV estimates the ______ a watershed.
soil water content of
some soil colloids exhibit negative charges under any PH conditions. To what are these charges likely due?
substitution of lower talent atoms for higher valent atoms in the octahedral sheets.
The amount of different sizes of mineral particles in a soil defines the soil
texture
Aluvial fans are most likely found where
the edges of cliffs, mountains, or bluffs where channelized water slows.
The process of soil formation is a complex interaction of
the four soil forming processes and five soil forming factors.
The soil profile consist of
the set of layers seen in a vertical cross section of a soil.
If you dug a deep hole in your back yard and water started to seep into the hole it would fill the hole up._____
the water table.
A polypedon or infdivudla soil is a group of closely related peons that conceptually approximate what in the United States is called soils series.
true
All of our lime sources use the same basic mechanics to neutralize soil acidity (Co3 or )H to consume H+)
true
HYdrolisis involves the splitting of water into its H+ and OH- components while hydration attaches intact water molecules to a compound
true
Igneous rocks are formed when molten magma cools and solidifies
true
Isomorphous substitution involves the substitution of one ion for another based on size.
true
Mollisols are found mostly near areas of natural nature or rangland
true
Soil and crop management generally has a greater influence on evaporation from the soil surface (E) than on transpiration (t) from leaf surfaces
true
The cation exchange capacity of humus increases if PH Increase
true
The two most significant characteristics of the slassfification 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
true
Tillage when the soil is too wet I likely to increase the soil bulk density
true
respiration is major cause of soil acidification
true
soil air usually has a higher carbon dioxide content than the air in the atmosphere.
true
soils tend to acidify naturally
true
igenous rock, sedimentary, and metamorphic are there
types of rocks
A soil has a thick black A horizon, a distinct B horizon has a reason stable soil structure and was formed under grassland natural vegetation. in which suborder is it most likely classified
udolls
In which of the following situations would you expect downward movement of soil water through the profile to be most rapid
uniformly textured sand loam profile.
Soil occupies the ________ part of the regolith.
upper
which of the following is not considered one of the five major factors influinincing soil formation
valence state
you are preparing to buy a lot for a house. while looking over some land you take a few minutes to dig a hole and check for the presence of slickensides. The slickensides idicate the presence of a ____ which would not be good place to build.
vertisol
which of the following best characterizes the field capacity of a soil.
water content of a soil with water potential of about -0.2 to about -0.3 bar
what drives the soil-plant-Air continuum
water potential
A soil with grey mottling occurring at >30" belongs to which drainage class
well drained
