Soil Science final
Card Set Information
Soil Science final
SS 121 Thomas Rice
Which of the following soil horizons would likely have the highest percentage of organic matter?
Which of the follwing conditions would result in the greatest soil development, assuming that all other soil forming factors are equal:
warm, dry climate, grass vegitaiton
soils on south aspects in the Northern Hemisphere generally ha _______ than soils on adjacent north aspects.
Less vegetative cover and warmer temperatures
Aspect is a component of which soil forming factor?
In the Northern Hemisphere, soil developement is most likely greatest on slopes which are:
B horizons are defined as zones of
Sediment deposits in teh bottom of fresh water lakes are called.
Parent materials transported by water and gravity are called, respectively:
alluvial and colluvial
an eolian deposit of silt sized materials is called:
As one travels from the Mojave Desert into the Sierra Nevada mountains, percipitation increases. one can expect the soil:
Organic matter content is higher in the mountains
Material deposited by moving fresh water is called:
soils formed from landslied deposits have parent materials which are
Loess is a wind deposited soil parent material. the material originally was
alluvium in large floodplains
Two landforms upon which one would expect to find alluvium include:
stream terraces and floodplaines
Alluvial soils are most often found on:
floodplains and lake shores
Aeolian parent materials would be mainly located on:
loess plains and sand dunes
the steeper the topography, usually the _____ the soil
younger and shallower
Climate is a soil-forming factor that resultsin:
regional soil defferences
The A horizon of a limestone- derived soil is more acid than the parent material due to:
higher carbonic acid levels
transported soil parent materials moved by wind and ice
eolian and glacial
Typically, the older the soil, the greater the:
number of different soil horizons
The most common mineral in limestone is:
Among the following minerals which one is an important source of K and clay soils?
The following minerals is a list of common igneous rock types:
rhyolite, obsidian, gabbro
the metamorphic rocks, gneiss and slate, are derived from
granite and shale
Primary minerals in igneous rocks form during the
cooling and solidification of magma
The two most abundant soil secondary minerals found in the clay-sized fraction of gabbro-derived soils are
montmorillonite and hematite
Vermiculite is derived from____ and has a physical property of_____.
muscovite; meduim shrink- swell capacity
A sedimentary rock composed of clay-sized mineral grains that are cemented together by silica is called
Igneous rocks are formed in water-contact lava and surface lava flows from felsic magma are called
obsidian and rhyolite
Ferromagnesian minerals weather easily and supply the soil solution with high amounts of
magnesium and iron
Montmorillonite is derived from____ and has the physical property of:
mica; low water - holding capacity
Igneous rocks are classified into different groups based on
silica content and rate of cooling
Among the following which one is recognized as an element
Muscovite is an example of a/an
The downward movement of material( e.g, humus, iron oxide, clay) out of soil surface horizon is called
Among the following weathering processes which one is most likely to produce clay- size minerals?
Among the following processes which one is
a physical weathering process?
Complete oxidationof iron in soils can result in
a mottled appearance
Which of the following essential elements is made available to plants in significant quantities by the weathering of quartz?
Which of the following essential elements for plants is released by the weathering of orthoclase feldspar?
NaAlSi3O8+HOH----> NaOH+ HAlSi3O8 is an example of
The following secondary clay minerals would be abundant in soils weathered from granitic alluvium:
montmorillonite and vermiculite
A mottled soil condition is caused by:
alternating oxidation and reducing conditions
The two conditions necessary for reduction of iron on soils are:
a lack of oxygen and some microbial activity
Hydrolysis of a sand-sized feldspar mineral grain would result in
a localized soil pH increase at the site of weathering
The two common products of hydrolysis weathering of primary mineral are
alumina, silica, and hydrogen in solution
Secondary minerals are found in
soils and igeneous rocks
The loss of soluble salta from soils occurs mainly by:
solution weathering and leaching
physical waeathering of rock causes:
particle size breakdown
the elements added to the soil solutionby mineral weathering can be
taken up by plants or leached
The following is a list of plant essential nutrients potentially supplied to the soil by mineral weathering
Mg, Fe,Mn, S, Mo
If you were to choose the best location for a building foundation on a level slope, you would want a soil high in
kaolinite clay and quartz sand
the downward leaching of calcium carbonate in soils is accomplished by
carbonation and solution
In a sandy soil subject to rapid downward leaching of water, which substances could move deeper into the soil than silicate clays?
The three most abundant elements in teh lithosphere are
silicon, oxygen, aluminum
The oxygen found in minerals in the lithosphere is
available to plants
The three most abundant gases in teh atmosohere are
carbon, hydrogen, oxygen
Then most abundant gases in teh atmosphere is
The percentage of sand, silt and clay in a soil define the soils
soil mottles are
-spots of color
-indications of alternating periods of oxidation and reduction in the soil
-indications of fluctuating water table
soils having which of the following textures would have the greatest aeration?
The unconsolidated and chemically weathered mineral or organic matter from which the solum of soils is developed by natural processes of soildeveloped is called
Which of the following is an example of a structureless condition in soil?
The negative logarithm in the definition of pH means that for each unit decrease in pH, the H+ concentration
decreases by ten times
The inflitration rate of water will be slowest in soils which are
The arrangement of primary soil particles into aggregates which are seperated by surfaces of weakness is called
the H+ concentration of soil solution having a pH of 4 is called
Which of the following soil horizons would probably have the highestcolor value?
illuvial accumulation of clay
illuviation of iron and alumminum oxides
farming disturbance of the topsoil
illuviation accumulation of carbonates
Percent porosity and soil bulk density are related. an increase in porosity results in;
a decrease in bulk density
one can decrease the soil bulk density by adding _____ to the topsoil:
humus compost high in calcium
Percipitation falling in excess of the soil infiltration rate is lost by:
Clay soils have higher average_____ values than sandy soils
total water holding capacity
Soil color is a result of:
mineral composition and organic matter content
One can increase the soil bulk density by adding _____ to the top soil
granitic sand and gravel
A clay loam soil with a pH of 9.5 will have a low:
soluble aluminum ion concentration
The active soil acidity is defined as the
hydrogen and aluminum in the soil solution
A clay soil, low in organic matter in the Mojave Desert, will have______ in its epipedon.
a low humus content
In order to convert and acid (pH4.0) soil into a productive (pH 6.5) agriculture soil, the best reclamation recommendation would be to:
add lime and thoroughly incorporate it into the soil
In an alkaline mineral soil derived from limestone, the following soluble cations will likely be present:
calcium, magnesium, potassium
A soil with high CEC will likely be composed of high amounts of:
vermiculite and humus
the soil pH will be ______ after 10 years, as a result of adding calcium carbonate to sandy soils
In order to convert an acid organic (pH4.0) soil into a productive (pH6.0) agricultural soil.
add lime and thoroughly incorporate it into upper foot of soil
Which of the following soil textural classes would you expect to have the lowest CEC?
Which of the follwing has the highest cation exchange capacity?
The clay mineral which is most often responsible for swelling and shrinking in soils:
Soils of which of the following textures can absorb and hold the greatest amount of air pollutants along heavily traveled highway?
The potential soil acidity is defined as the
aluminum and hydrogen on the cation exchange complex
the following are acid cations abundant in pH 4.5 soil
In an alkaline mineral soil derived from dolomite, the following cations will likely be present:
Soil pH is a measure of:
hydrogen ions in the soil solution
In order to convert an alkaline (pH9.5) soil into a productive (pH 6.5) agricultural soil, the best reclamation recomindation would be to
add phosphoric acid, sulfur and organic matter to the topsoil and thoroughly incorporate it
In an acid mineral soil derived from granite, teh following cations will likely be present:
The following buffer compounds tend to maintain an alkaline soil pH
calcium and sodium carbonates
The optimum pH range for maximum plant nutrient availability is
6.5 to 7.5
A loamy sand soil, high in organic matter in redwood forest. will have______ in its epipedon.
a low percent basic cation saturation
A clay soil derivede from basalt would contain high amounts of:
montmorillonite and iron oxides
The active soil acidity is defined as the
hydrogen and aluminum in the soil solution
Calcium is considered a_____ cation and is derived from the weathering of ____
in an acid (pH 4.5) mineral granite- derived soil, the following soluble cations will likely be present:
in order to convert an alkaline mineral(pH 9.0) soil into productive (pH 6.5) agriculture soil, the best reclamation recomendation would be to
add sulfuric acid and organic matter to the top soil and thoroughly incorporate it
In an acid mineral soil derived from granite. the following cations will likely be deficient
The more vermiculite clay and organic matter a soil has, the greater its:
cation exchange copacity
The following buffer compounds tend to maintain an acid soil pH
carbonic acid and humus
Soil buffering capacity can be increased by adding _____ to the top soil
organic matter and calcite (has hydrogen)
The material which is most often added to acid soils to raise the pH is
The most common acid found in all A horizons is
Which of the following textures has the highest cation exchange copacity, assuming that they all have the same organic matter content?
In an acid, organic soil, the following cations will likely be present:
hydrogen, ammonium, aluminum
soils can be acidified by incorporating ______ to teh top soil
The soil pH will be ______ after 10 years, as a result of adding ammonium-nitrogen fertilizers to sandy soils:
The exchange complexes of strongly acid (pH 4.5) mineral soils are saturated mainly with
exchangeable Al3+ ions
In the B horizons of which order would you most likely find a soil with the highest buffering capacity?
How does the amount of lime needed to neutralize the residual acidity in clay loam soil compare to that needed to neutralize the active acidity in that soil?
residual takes 10 times greater
Which of the follwing human actions is most apt to result in a long term increase in soil pH?
irrigation with high sodium salt containing waters
the drainage of certain wetlands can resulted in extreme soil acidity because____
oxidation of sulfer bearing minerals that produces sulfuric acid
Which of these elements is most likely to be toxic to plants in a soil pH 4.0?
Phosphorus availability is very low in most strongly acid soils because of its reaction with
Assume you want to grow azaleas in a soil with a pH of 6.0. the application of which of the following would be most appropriatw to make this soil suitable for this ornamental?
If you want to quickly increase the pH of a soil from 5.5 to 7.0 which of the following would you use?
Under which of the following conditions would you favor a finely ground dolomitic limestone as your choice among liming minerals?
need to provide magnesium in addition to calcium
Which of the is likely to occur when lime is added to the surface a soil pH 6.0?
CO2 in the soil air helps solunilize the CaCO3 and increase its rate of downwardmovement
In humid regions, applications of limestone are repeated every few years primarily because of
increased rates of formation of carbonic acid
The very high pH levels found in some arid region soils are most likely due to high levels exchangeable
Poor plant growth in well-drained irrigated Ardisol (pH=8.0) is most likely due to ___
The CEC of alkaline soils are generally higher than those of most acid soils of similar texture. Which of the following characteristics of alkaline soils most likely accounts for this high CEC?
high content of 2 1 clay types
A homeowner in new mexico attempted to grow azaleas in well drained soil (7.5) but the plants were stunted and the leaves were yellow. what is the most likely cause of this constraint?
Some irrigation systems have stimulated the formation of saline and saline-sodic soils. which of the following contributes to this process?
inadequate drainage systems to remove soluble salts
Saline soils are charicterized by
low chloride and sulfate contents
Saline -sodic soils are characterized
all but which one
of the following?
CaCO3 layer near the soil surface
Soil physical conditions began to deteriorate and crop yields began to decline several years after farmer started irrigating a field. which of the follwing most likely account for this solution?
high SAR of the irrigation water
Which of the following plants would most apt to tolerate soil salinity?
Which of the following characteristicsof irrigation water is most apt to stimulate the formation of high sodic soils?
high SAR values
If you want to reclaim a saline -sodic soil, which of the following practices would you most likely use?
Leach the soil with water high in Ca2+ and Mg2+
you were advised to use elemental sulfur in the reclemation of saline-sodic soil. Indicate how the sulfur helps bring about this reclamation.
sulfur is oxidized and forms sulfuric acid which, in turn removes the exchangeable Na+
Gypsum is the most widely used chemical for the reclamation of sodic soils. what characteristic likely accounts for this popularity?
gypsum is abundant and low priced
Sodic soils generally have a poor physical condition. This is most likely due to
dispersal of the Na saturated soil colloids
Available phosphorus levels are constrained in alkaline and salt-affected soils because of
high calcium and magnesium levels
Attempts phosphorus levels are constrained in alkaline and salt-affected soils because of____
increase in percentage sodium saturation
Which of the following comparisons of the three different classes of salt-affected soil is correct?
Saline soils are generally higher in soluable salts than saline sodic soils
The growth of plants on sodic soils is constrained by
all but one
of the following
toxicity of very high levels of calcium carbonate
The degradation of irrigated soils across the once very productive "fertile Crescent" of the middle east was due primarily to
poor internal drainage and high watertables within the soils
which of the follwing best describes a sodic soil?
EC= 1 mmhos/cm; ESP= 25%; pH= 9.5
Which of the following would be the best management recommendation for sodic soil reclamation?
add gypsum, add sulfuric acid, and leach
Which of the following is
a potential source of salt in soils?
eolian quartz sand
Which of the following soil parent materials would not be a potential source of soluble salts in soils?
High sodium contents in clay loam soils often result in:
decreased permeability rates
In order to convert a saline soil to non- saline, which treatment would be the best management recommendation?
irrigate with good quality water
Which of the following best describes a saline soil?
EC=20mmhos; ESP=10%; pH=7.5
(158)Which of the following groups of soil orginisms are responsible for greatest amount of organic matter decomposition in soils?
Which of the following microorganisms can commonly be seen with the unaided eye in organic matter-rich soils?
Compared to the bulk soil in which earthworms live, earthworm casts contain
more of most plant available nutrients
In nature, beneficial mycorrhize form with the roots of___
broad leaf trees
In most soils the overall population of microorganisms changes with time, generally following changes in the
supply of decomposable organic matter
Memebers of this(these) microbial groups are resposible for a major proportion of nitrogen fixed globally in symbiosis with higher plants
(168)Oxidation or reduction of inorganic soil constituents such as iron and sulfur is carried out by members of which group of microorganisms
Nearly all organic compounds from which living beings are made have as thier backbone, chains or rings of____ atoms
Which of the following are major sources of the carbon dioxide now being added the atmosphere in excess of the amount taken out by plants?
loss of soil organic matter
destruction of natural forests
burning of fossil feuls
Which of the following is a greenhouse gas contributed to the atmosphere by soils?
after drying to eliminate the water in plant litter, which two elements account for about 80% of the dry weight?
c and h
Humic substances consist of ___
living organisms and cells
dead plant and animal tissues
polymerized non identifiable molecules
Soil irganic matter consist of ____
dead tissues and wastes
One would expect well drained soils to have the highest organic matter contents where the climate is ____
cool and wet
Soils with thick horizons consisting mainly (>30% by weight) of organic matter and that form in topographic depression or low -lying places usually belong to the soil order.
A soil low in organic matter is most likely to be deficient in whicj esssential element for plant growth?
in aerobic respiration by microbes_____ is absorbed, and ______ is released
oxygen, carbon dioxide
The terms nitrification and nitrogen fixation are often confused. Nitrification actually means
the biochemical oxidation of ammonium to nitrate
a mechanism of loss of nitrogen from the total soil system?
Which of the following is an example of nitrogen immobilization?
absorption of nitrate ion by a bacterial cell
The conversion of nitrogen gas to a plant available form of nitrogen is accomplished nitially through the process of
symbiotic nitrogen fixation
Nitrogen immobilization in soils occurs as a result of
adding high C N ratio organic matter
Humus in soils is
a by product of organic matter decomposition
Organic matter decomposition is increased by
adequate soil aeration
The three nutrients whose availability to plants is most directly related to the decomposition of organic matter in soil are:
nitrogen, phosphorous and sulfur
Soil air differs from the atmosphere we breath in that:
Soil air has higher carbon dioxide content
organic matter influences many soils properties organic matter causes
increased soil water- holding capacity
As the percentage of soil organic matter is decreased due to poor crop management. generally the:
bulk density increases
the C N ratio of organic materials refers to the
carbon to nitrogen ratio
Nitrogen is a component of which essential plant compounds
a deficiency of N typically _____ the maturity of annal plants
Applied to agricultural crops, the term lodging refers to
plants falling over, often as a result of too much N
In early stages of plant nitrogen deficiency, the most obvious symptoms are
yellowish colors in the oldest leaves
Plsnts obtain nitrogen from the soil by taking up
soluble organic compounds
the greater majority of nitrogen (95 to 98) in soils can be found in the form of
The process of_____ releases soluble nitrogen as the result of the breakdown of nitrogen- rich organic compounds
The opposite process from mineralization is
Ammonium fixation would be expected to be greatest in soils containing a lot of
Ammonia losses are likely to be greatest if a nitrogen source is placed about 10cm deep in
a calcereous sandy loam soil
Methemoglobinemia is principally a potential threat to
babies drinking water high in nitrate
Compared to gypsum, elemental sulfur is sometimes considered a more desireable fertilizer material because
it contains more nutrient sulfur, kilogram for kilogram, the gypsum
Because of ______ soils developed in marine marshes can become ectremely acid if drained ofr agriculture or used as topsoil
oxidation of sulfides
The drainage class of a soil is directly related to
water table depth
A reddish brown soil located on an upland landscape position is
the soil with more macropores will have:
rapid inflitration rate and low water holding capacity
a grayish loe chroma soil located on concave valley landscape position is most likely to be
very poorly drained
the seasonally high watertable of a soil determines its:
the soil with more micropores willl have
slower inflitration rate and higher water holding capacity
Many agricultural soils in the SW san juaquin valley_____ in thier topsoils
sodium carbonate and chlorides
Large areas of western Fresno Co. are subject to subsidence due to______
overburden pressure caused by agricultural crops and houses
Vernal pools are
depressional areas that form seasonal wetlands due to water ponding
Organic matter decomposition within the sacramento Delta islands causes
subsudence of the land and destruction of human structures
Many agricultural soils in the talure lake basin have ____ in thier subsoils
sodium carbonate and chloride salts
The sodium near Mount Lassen are weathered from
volcanic ash and igneous rocks
Land leveling of agricultural soils of the San Joaquin Valley causes
natural topsoils to be buried and subsoils to be exposed at the surface
subsoil drainage systems in agricultural soils helps to
remove chloride salts from the soil
Enviornmental concerns related to agricultural soil drainage systems include
disposal of drainage water containing salts and toxic elements
Mechanical ripping of soil hardpans in the eastern San Joaquin valley causes
improved rooting depths for perennial tree crops
Irrigation of agricultural soils in the San Joaquin Valley results in
increased humidity and moisture levels in the atmosphere
Subsudence of soils in the western Fresno Co. area causing
cracks to form in walls of teh california aqueduct