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45 Cards in this Set

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For a structural engineer, which type of clay would provide the most troublesome site on which to build home/road?
Smectite
The structures of 2:1 clay minerals are so-named because they contain _______________.
two tetrahedral layers for every octahedral layer
Isomorphous substitution creates net negative charges in clay micelles. A typical example of this process is the substitution of __________.
Mg2+ for Al3+ in an octahedral
What would be the net charge of a neutral soil colloid if Si+4 is replaced by Al+3 in the tetrahedral sheet?
negative
Which of the following soil is expected to have the highest acidic cations as the percentage of CEC?
ultisols at pH 4.4
________ is expected to be dominant in the warm and humid soils of Alabama compared to arid Nevada.
kaolinite
_______________ is the sum total of exchangeable cations that a soil can adsorb.
Cation exchange capacity (CEC)
In general, the CEC of ________________ is more significantly affected by soil pH.
Al-oxides
Fe-oxides
humus
Relatively speaking, as weathering intensity increases, the CEC of a soil will _____________.
decrease
The colloidal fraction of the soil is the seat of soil cations and anions where soil physical and chemical reactions take place.
True
The cation exchange capacity of a soil is affected by:
type of soil colloids
amount of soil colloids
soil pH
Which of the following cations are closely associated with soil acidity?
a. Ca+2 and Mg+2
b. K+1 and Na+1
c. OH-1 and CO3
-2
none of the above
As soil pH increases, the acid saturation of the soil colloid will:
decrease
A soil at pH 3.5 has _______________ H+ concentration compared to a soil at pH 5.5.
100X more
Soil acidity is defined as –log ___
(H+)
If a plant root absorbs more SO4
-2 from soil solution without an accompanying anion, the pH of the
surrounding soil solution will:
increase
As soil pH decreases, the concentration of which of the following three essential nutrients will increase?
a. Fe, Mo, B
b. Mo, Mn, Zn
c. Mo, Zn, Fe
d. Fe, Zn, Mn
Fe, Zn, Mn
Addition of ammonium nitrate fertilizers to soil in general will _________________ soil pH.
decrease
During your lab exercise on soil acidity,soil pH was determined by:
a. pH meter
b. dye
c. both a and b
d. none of the above
c. both a and b
Which of the following soil is relatively expected to have the highest CEC?
a. a sandy soil with 2% organic matter
b. a clay soil
c. a clay soil with 2% organic matter
d. all will have about the same.
c. a clay soil with 2% organic matter
The ability of a soil to resist changes in pH is called:
buffering capacity
The percent calcium carbonate equivalent of MgCO3 is:
119
Soil pH value is more or less a permanent property and can not be manipulated in less than ten years time.
false
You will be more apt to find salt affected soils in which of the following state?
a. Georgia
b. Montana
c. Mississippi
d. Alabama
b. Montana
Soil physical conditions began to deteriorate and crop yields began to decline several years after a farmer started irrigating his field. Which of the following most likely accounts for this situation?
a. high content of Ca and Mg in the irrigation water
b. failure to use conservation tillage to reduce salt accumulation at the soil surface
c. high SAR and ESP in the soil and irrigation water
d. excessive drainage of the soil
c. high SAR and ESP in the soil and irrigation water
The formula [Na+]/(0.5([Ca2+] + [Mg2+])1/2 is an expression of:
SAR
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.
Irrigation water that has an initial 20 ppm selenium concentration is used again and again at lower lying
agricultural fields. The selenium concentration in the irrigation drainage used by the last field would be:
a. less than 20 ppm
b. more than 20 ppm
c. 20 ppm
d. none of the above
b. more than 20 ppm
If a solution that contain 200 g of salt and 4000 g of water is allowed to evaporate to 50% of its original volume, the amount of salt left in the solution will be:
200 g
A micronutrient that can be toxic to plant at soil pH>8.5 is:
a. Al b. Zn c. Mn d. Mo
d. Mo
Biosphere II did not work as planned because the role of _____________ was neglected.
microbes
Since 1950s, more than 500 antibiotics have been isolated from:
a. nematodes
b. algae
c. actinomycetes
d. earthworm
c. actinomycetes
In general, microbial growth and activity is directly dependent on:
soluble food
In a given ecosystem, an organism A produces substance X that benefits organism B, but the substance has
no benefit for organism A. This association is a good example of:
a. parasitism
b. commensalism
c. amensalism
d. mutualism
b. commensalism
Genetically engineered microorganisms are:
a. are result of recombinant DNA
b. have no use at all
c. science fiction
d. rhizosphere.
a. are result of recombinant DNA
By any standard of measurements, earthworms have ____________ digestion system.
a. an efficient
b. an inefficient
c. super efficient
d. none of the above
b. an inefficient
Phosphorus will be fixed by ________ and _________ in alkaline soils and may not be available for plants.
a. Ca and Al
b. Al and Fe
c. Al and Mg
d. Ca and Mg
d. Ca and Mg
Under normal conditions, ____________ moves from the air atmosphere to soil atmosphere while __________ moves from soil atmosphere to air atmosphere.
O2, CO2
The quantity of soil air is related to:
the proportion of pore space that is filled with air/water
Anaerobic respiration of microorganisms produces significant amount of which of the following gas?
a. CH4 (methane)
b. O2
c. N2
d. CO2
a. CH4 (methane)
If the temperature of a soil were to increase from 10 to 20 degrees Celsius, you would expect the rate of
microbial activity (such as organic matter decomposition) to _______________.
increase by 100%
Which of the following process is true about soil temperature?
a. It fluctuates more in the subsoil soil than surface soil.
b. Subsoils are generally warmer in late fall and winter, but cooler in spring and summer.
c. In Alabama, soils facing north will be warmer than
those facing south during winter.
d. none of the above.
b. Subsoils are generally warmer in late fall and winter, but cooler in spring and summer.
The primary characteristics of subsoils that account for the ability of ground circulating heat pumps to moderate temperatures is?
the high specific heat and low heat conductivity of the soil
Benefit of wetlands does not include:
a. flood protection
b. methane production
c. water filtration
d. none of the above.
b. methane production