Soil Final Exam Flashcards
Which one is an epipedon
mollic
Dry soils with ochric epipedons, may have calcic subsurface horizon
aridisol
Soils that have permafrost within the upper horizons
gelisol
Which epipedon is human made?
Plaggen
Soils containing high amounts of organic matter and low bulk density, and develop under water-saturated conditions
histosol
Soils developed in volcanic ash deposits that are often composed of amorphous (non-crystalline) compounds
andisol
The order Spodosol, by definition, must have what diagnostic horizon
spodic
Soils high in swelling-type clays, deep cracks form at the surface when dry
vertisol
Moderate to high base saturation (>35%) in the argillic or natric diagnostic horizon
alfisol
Soft, dark-colored soils of grassland areas, >50% base saturation in surface horizons
mollisol
metamorphic form of limestone
marble
Contains an accumulation of silicate clays
Bt1
The mineral part of the pedosphere
lithosphere
Where is the highest point of elevation in Missouri?
Taum Sauk
Which texture has the most total pore space?
fine-texture soil such as clay
KAlSi3O8 + H2O → HAlSi3O8 + KOH where water reacts to form a more soluble compound
hydrolysis
materials moved in large landslides are this type of material
colluvial
In a horizon 2Bx1, the 1 indicates the
the subdivision of the subordinate horizon
Which bulk density value (g/cm3) is most likely an O horizon
0.6
the subordinate in 2Bx3
x
Horizon most likely to have granular structure
Ap
The top-most mineral horizon
A
The soil most likely to be well-drained (aerated)
7.5YR 4/6
CaCO3 → Ca2+ + CO3 2- is an example of a breakdown into ions
dissolution
Which bulk density value (g/cm3) would most likely restrict root growth
1.8
an alluvial fan is made of materials that have been
wahed down by water at the base of a slope
Horizon most likely to have angular blocky structure
Bt
What is a “loam” soil?
a soil that exhibits properties of equal amounts of sand, silt, and clay. The texture is not equal amounts of sand, silt, and clay however. Clay has a strong influence on soil properties, so a loam soil is a textural class with less than 33% (1/3) clay.
breakdown of rocks into smaller sizes, without a change in composition
physical weathering
The zone of maximum eluviation is the master horizon
E
cultivation (plowing) of a soil for may years will cause the bulk density of the A horizon to
increase over time
Indicates the redness or yellowness of a soil
Hue
shale
sedimentary clay
Has the greatest amount of surface area per unit volume
clay
0.0015 mm diameter particle
clay
organic matter being carried to the B horizon by an ant collony (or cheetas)
translocations
Most (over 95%) of soils in Missouri are
mineral soils
The particle density of a soil will always be ________ the bulk density of the same soil
Greater than
drumlins and morains are made from this type of deposited material
glacial
oxidation of iron minerals in B horizon
Transformations
Percent of the Earth’s entire crust suitable for food production is
about 3% (1/32)
Which statement is true about the official state soil of Missouri?
primarily silty
rock made from the reformed sediments from the breakdown of other rocks
sedimentary
part of the soil color that changes when a dry soil becomes wet
Value
5.00 mm diameter particle
coarse fragment (not a soil separate)
type of rock formed directly from molten/volcanic materials
igneous
chemical reaction of iron compounds in the soil exposed to oxygen and “rusting”
oxidation-reduction
humans spreading fertilizer on soil surface
additions
Stoke’s Law indicates that this soil separate is the first to fall out of a soil suspension and settle out of solution
sand
Horizon not included in the “solum”
C
The zone of maximum illuviation is the master horizon
B
Contains a fragipan
Bx2
parent material usually found in flood plains
alluvial
of the choices below, what soil would have the most sand?
loamy sand
Indicates water logged conditions for prolonged periods of time
a low chroma
When texturing a soil by hand, pressing the soil between your thumb and fore finger into a thin length until it breaks apart is a process called
ribboning
someone who studies soil from the standpoint of profile development, classification, and descriptions would be called a
pedologist
More organic matter in a soil will be indicated in the color by
a lower value
0.20 mm diameter particle
sand
granite
igneous
The soil most red in hue
2.5YR 5/7
CaSO4 +H2O → CaSO4.H20 in which water is incorporated
hydration
Elephant Rock state park has examples of __________ rock, when a majority of the bedrock in Missouri is ______________.
igneous; sedimentary
sand dunes are made by these types of transported materials
eolian
A transition horizon
BC
loess hills of NW Missouri and Eastern Iowa are made of this type of material
eolian
When texturing by hand, a “gritty” feel indicates
more sand in the sample
In a horizon 2Bt3, the 2 indicates the
a change in parent material
In a video we watched Dr. Weil, one our our authors of our textbook, described a soil condition of a plow pan. Describe the soil condition he was talking about and how it was formed. Discuss one way to improve this condition in the soil.
Dr. Weil was describing a plow pan, a layer of compacted, higher density soil caused by machinery and plowing of soil. This density causes roots not to grow into that layer and restricts water movment, so essentially we are groing crops with roots only in the top 6-10 inches of the soil and not utilizing the soil depth of our fields. Ways to improve a plow pan would be to grow deeply rooted plants and ones with large taproots. Another way we talked about in class was to use machinery to deeply knife/rip the soil past the plow pan depth.
basalt
igneous
What are the 5 factors of soil formation?
Parent material
Climate (temperature and rainfall)
Biota (living organisms)
Topography (relief)
Time
Indicates how brightness or dullness (gray) of a color
Chroma
type of rock that has been changed due to high temperature and pressure
metamorphic
organic parent materials made from woody plant material
terrestic peat
What is the difference between soil texture and soil structure?
soil texture is the relative amounts of sand, silt, and clay in the soil. structure is the arrangement of sand, silt, clay, and OM (the shapes that are made).
In the color 5Y 3/4 the value is
3
Isomorphic substitution in the octahedral sheet
Aluminum is removed and replaced with magnesium
bentonite, used to seal to bottom of ponds, is this type of clay
Montmorillonite
A tetrahedron is a
four-sided structure with a Si in the pore
“tropical clays”, iron and aluminum oxides
Oxide-hydroxide clays
Which statement is true about soil pH?
nutrient availability for plant uptake can be affected by soil pH
If the pHw of a soil is 6.0 then the pHs is about equal to
5.5
What causes some clays to be considered “shrink/swell” clays that expand in volume when wetted? What causes other types of clays to not shrink/swell?
1) shrink/swell clays expand in volume due to its large interlayer between the sheets of its crystalline structure. Water can enter the interlayer and expand the volume of the clay.
2) Clays that don’t shrink/swell do not have a space in the interlayer, it is either small or closed off so water cannot get in.
Of the colloids listed, which one has the lowest CEC
Oxide-hydroxide clays
Organic colloids have a large CEC because of
A large number of pH dependent sites
In general, the lower (smaller number) the % Base Saturation of a soil, the ______ the pH of the soil.
Lower (smaller number)
Neutralizable Acidity is a measurement of which pool of acidity in a soil?
Exchangeable acidity
the negative logarithm of the hydrogen ion concentration
pH
BONUS: the pH of CocaCola (or any cola) is about
2.2
A 2:1 clay structure indicates each layer is
Tetrahedral sheet: octahedral sheet: tetrahedral sheet
An octahedron is
An eight-sided structure with an Al in the pore
What is the “buffering capacity” of a soil? How does CEC of the soil affect buffering capacity (what is the general relationship between CEC and buffering capacity)?
1) buffering capacity is the ability of the soil to resist changes in pH
2) the greater the CEC, the greater the buffering capacity
pH is a measurement of
Active acidity
Ol’ MacDonald had a farm, and on that farm he spread some nitrogen fertilizer. He choose to spread nitrate (NO3) based fertilizer, rather than ammonium (NH4) based fertilizer. How should Ol’ MacDonald expect his soil pH to change as a result of appying nitrate? (1pt) EXPLAIN how each of these fertilizers, both ammonium and nitrate, affect soil pH and why they do so. (4pts)
Ol’ MacDonald should expect his soil to become less acidic (higher pH).
When ammonium is present, the roots of plants release a hydrogen into the soil in order to take up an NH4+. The addition of hydrogens in the soil will lower the soil pH, making it more acidic. WHen nitrate is present, roots take up 3 H+ with it, reducing the acidity in the soil solution and raising the pH of the soil.
What is the difference between active acidity, exchangeable acidity, and residual acidity in a soil?
active = hydrogens in soil solution; exchangeable = hydrogens adsorbed to soil colloids exchange sites (negative sites, CEC) that can easily exchange into solution; residual are hydrogens strongly imbeded in the colloid structure and will not exchange off the colloids into solution.
One way a land owner could manage their soil to increase the soil CEC would be to
Manage the soil to increase % organic matter
2:1 limited expanding clay
Vermiculite
permanent negative sites in silicate clays are caused by this
isomorphic substitution
2:2 (2:1:1) non-expanding clay
Chlorite
1:1 non-expanding clay
Kaolinite
A pH of 6.0 has __________hydrogen ions than pH 4.0
100 times less
BONUS: the most abundant metal in the Earth’s crust
Al
Of the colloids listed, which one has the greatest CEC?
Humus
2:1 highly-expanding clay
Montmorillonite
A 1:1 clay structure indicates each layer is
tetrahedral sheet: octahedral sheet
Which soil would have the greatest CEC?
15% organic matter and 20% clay
commonly used for clay pottery due to its low shrink/swell potential
kaolinite
pH dependent negative sites in silicate clays are caused by this
ionization of hydrogen
Neutralizable Acidity is a measurement of
Adsorbed hydrogens
The general range of soil pH where nutrient availability is maximum for plants
5.5-7.0
A pH of 5.0 has __________hydrogen ions than pH 6.0
10 times more
A non-expanding (does not shrink/swell) clay
illite
Is an organic colloid
Humus
the total exchangeable cations a soil can adsorb
cation exchange capacity
“Permanent or constant” negative sites of silicate clay structures arise from
Isomorphic substitution within the tetrahedral or octahedral sheets
2:1 non-expanding clay
Illite
pHw is a measurement of
Acidity in soil solution
Across the world, many people grow crops on acidic soils. A big problem that can occur for the plants growing on acidic soils is
aluminum toxicity
Which fertilizer contains both N and P
monoammonium phosphate
Bonus question (2pts) What is Milorganite?
biosolids from Milwauke WI
Another term for “humus”
stable organic matter
is applied as a calcium fertilizer but also used to stabilize soil structure
Gypsum
Organisms that create their own food from inorganic sources are
Autotrophs
Soil microbes use which mechanism to make nutrients available to plants?
Produce of enzymes
Alter the soil pH
Produce organic acids
Dissolve minerals
Calcitic Limestone is
Calcium carbonate
Dolomitic Limestone is
Calcium magnesium carbonate
The capacity to carry out a variety of biological processes describes what?
Functional diversity
The breakdown process of organic matter to a useable nutrient form is
Mineralization
Fungi in the soil that help symbiotic plants gain nutrients from the soil
mycorrhizae
What does ENM stand for? What two properties of lime are involved in determining the ENM value of the lime?
Effective neutralizable material (1pts). Purity (calcium carbonate equivalent) and size of the partilces/grind. (4pts)
Assume for a tomato crop you need to lime with calcitic limestone. The local limestone dealer has a source there with an ENM of 430 and a source with an EMG of 40. The soil test report suggests 520 ENM and 55 EMG. How much calcitic limestone should you apply in tons/acre? Show all work. Round to two decimal places. Include units in your answer.
Calcitic = ENM of soil test / ENM from dealer =520/430 = 1.21 tons/ acre
The process of microbes converting nitrogen gas (N2) from the atmosphere into compounds useable by plants is
Nitrogen fixation
The decomposition rate of soybean residue is much faster than corn stover because soyben residue has
a carbon to nitrogen ratio less than 25:1 (much more nitrogen)
How much of 0-46-0 fertilizer would you apply to meet one of the nutrient requirements from a soil test report suggesting 55 pounds per acre N, 35 pounds per acre P2O5, and 45 pounds per acre K2O. Show all work. Round your answer to one decimal place. Include units in your answer.
lbs fert = lbs nutrient/% in decimal form
0-46-0 46 is your percent P2O5. Decimal form: 0.46
lbs fert = 35 lbs P2O5 / 0.46
76.1 lbs per acre fertilizer 0-46-0
A “complete” fertilizer
13-13-13
What is the difference between active organic matter and stable organic matter in soil?
active organic matter as the portion that is decomposing. (2pts) stable organic matter is the result of decomposition (can take many years and decades to form) (2pts)
is applied as a magnesium fertilizer
Epsom salt
If the %Mg saturation of a soil is 8.2% and you want to grow a hay crop for beef cattle (for animal consumption). The soil test report recommends applying limestone. What type of lime should you apply, calcitic or dolomitic? Explain your answer.
Hay crop is for animal consumption, so use the 10% Mg cutoff rule.(1pt) 8.3% is less than 10% so you need to add Mg (2pt). Add DOLOMITIC lime because it has Mg. (1pt)
A 10-20-30 fertilizer is equilavent to
20% by weight phosphate
What form of fertilizer does a plant prefer to take up? organic or mineral
plant does not prefer one source over the other, as long as the nutrient is in an available form in the soil
0-0-60
Murate of potash
In a 50 pound bag of 26-12-5 fertilizer, how many pounds of potash equivalent does it contain? Show all work. Round your answer to one decimal place. Include units in your answer
lbs of fert = lbs of nutrient / % of nutrient in decimal form
50= lbs K20 / 0.05
50*0.05=
2.5 lbs potash
The EMG stated on Missouri soil test reports is used to
Determine the dolomitic limestone recommendation application rate
Applications of limestone on soils will
increase the soil pHw
46-0-0
Urea
0-46-0
Triple super phosphate
micronutrient in a chelated form
Zn-EDTA
liquid N fertilizer that is injected as a liquid into the soil to decrease volatilization
Anhydrous ammonia
Makes up a majority (60-90%) of the total organic matter in the soil
stable organic matter
The most abundant nutrient added to cropland as fertilizer worldwide
Nitrogen
Jane would like to grow blueberries in her yard but knows she needs to make her soil more acidic. Which fertilizer could she apply to do this?
Elemental sulfur
82-0-0
Anhydrous ammonia
a source of potassium
Murate of potash
Which type of fertilizer will cause the soil pH to decrease, ammonium-based or nitrate-based? And, why does the soil pH decrease overtime?
ammonium based fertilizers decrease soil pH (1pt) Plant roots take up ammonium and release a H+ into the soil, decreasing soil pH (4pts)
What is the %Mg saturation of a soil with test results of the following: P = 25 lbs/A, K =298 lbs/A, Ca=2140 lbs/A, Mg=250 lbs/A, Organic matter = 2.2%, N.A.=1.0 meq/100g, CEC = 7.77 meq/100g? Show all work. Round to one decimal. Include units in your answer.
Correct
%Mg = lbs Mg/ 240 *100 / CEC
= (250/240)*100 / 7.77
= 13.4%Mg
What is not a role of soil organisms?
Soil erosion
A nitrogen fertilizer that often has losses from volatilization if unproperly applied
Urea
The following land capability classes are recommended for cultivation according to the USDA Land Classification System
Classes 1-4
An example of a soil phase
Hoberg silt loam, 1-5% slopes
What is the family of: Adelaide silt loam, 2 to 8 % slopes, a loamy, mixed, superactive, mesic, shallow Cambidic Haplodurids
a loamy, mixed, superactive, mesic, shallow Cambidic Haplodurids
The most generalized (least specific) category in Soil Taxonomy
Order
What is the subgroup of: Nard ashy loam, 25 to 45 percent north slopes, a fine-loamy, isotic, frigid Vitrandic Haploxeralf
Vitrandic Haploxeralf
The term for the system to classify soils based on measurable soil properties (morphological, chemical, mineralogical)
Soil Taxonomy
soils most likely found in Hawaii, due to being formed from volcanic ejecta
andisols
The official soil series of Missouri is
Menfro
What is the Order of: Adelaide silt loam, 2 to 8 % slopes, a loamy, mixed, superactive, mesic, shallow Cambidic Haplodurids
aridisol
A soil that was recently deposited during a flood event, such as along the Missouri River floodplain, would be a
Entisol
Histosols have this epipedon, very high in organic content
histic
Which soil has a Great Group describing “no distinquishing features”?
Cedargap very gravelly loam, 1 to 3% slopes, occasionally flooded, a loamy-skeletal, mixed, superactive, hyperthermic, Cumulic Hapludolls
In Missouri soil surveys, the soil map uses this taxonomic group as map units
Phase
A surface diagnostic horizon high in organic matter like a mollic, but low in base saturation (less than 50%)
umbric
What is the Order of: Owyhigh-Ipsut-Tipsoo complex, 25 to 100 percent slopes, a medial, glassy Andic Haplocryods
spodosol
synonymous with the term polypedon; consists of soils that are similar in profile characteristics such as color, texture, and structure
Soil series
An example of a soil with a mean annual temperature of 15-22 degrees Celsius (common to southern Missouri)
a clayey, mixed, active, thermic Typic Hapludults
The most specific category in Soil Taxonomy
Series
a mapping unit used in detailed soil surveys where two or more taxonomic units are so intermixed that it is impractical to separate them
Soil complex
Which soil is most likely the youngest, least weathered and developed (considering the Order of each soil)
Cedar loam, 0 to 2% slopes, occasionally flooded, a loamy-skeletal, mixed, superactive, hyperthermic, Cumulic Haplaquent
An example of a soil with a mean annual temperature of greater than 22 degrees Celsius (common to tropical climates)
a fine-loamy, siliceous, superactive, hyperthermic Aquic Hapludalfs
a three-dimensional volume of soil extending from the surface downward to the depth of plant roots; the smallest unit that is called a “soil”
Pedon
If your land has a Capability Class of ________, you should not crop it and only leave it for wildlife habitat
Class 8
Which soil has a Great Group describing “old land surfaces”?
Moniteau silt loam, 1 to 3 % slopes, rarely flooded, a fine-silty, mixed, active, thermic Typic Paleaquult
a grouping of soils found together in a geographical area that consists of 2 or more soil series
Soil association
the term for diagnostic horizons that occur at the soil surface (surface diagnostic horizon such as mollic or umbric)
Epipedons
A soil containing a fragipan subsurface diagnostic horizon would have the genetic horizon
Bx
A subsurface diagnostic horizon that oxisols must contain
Oxic
A soil containing an argillic subsurface diagnostic horizon would have the genetic horizon
Bt
Which soil is under humid climates (identified by the suborder prefix)
Alsup cobbly silt loam, 8 to 15% slopes, a fine, mixed, active, mesic Typic Fragiudalf
The Land Capability Subclass that is limited for production due to a susceptibility to erosion
3e
Eventhough it can get cold here in Missouri, these soils are not found in MIssouri. They contain permafrost
gelisols
What is the suborder of: Alsup cobbly silt loam, 8 to 15% slopes, a fine, mixed, active, mesic Oxyaquic Fragiudalf
Udalf
What is the series of: Nard ashy loam, 25 to 45 percent north slopes, a fine-loamy, isotic, frigid Vitrandic Haploxeralf
Nard
a diagnostic subsurface horizon of silicate clay accumulation
argillic
The farmland classification that designates a soil as not the best combination of characteristics for crop production, but is used for the production of specific high-value food and fiber crops (such as vineyards in Missouri)
unique farmland
What is the greatgroup of: Nard ashy loam, 25 to 45 percent north slopes, a fine-loamy, isotic, frigid Vitrandic Haploxeralf
Haploxeralf
Of the soils listed, these would be considered the most weathered and acidic
ultisols
Karls Hall was built on
Creldon silt loam
Which soil order is NOT found in Missouri?
Aridisol
