A Quizzes - Part 1

Question 1

A catio which enhances flocculation of clay mineral is:

A. Na⁺

B. Ca²⁺

C. Water

D. Methanol

Answer 1

B. Ca²⁺

Question 2

Over the long term, tillage affects soil bulk density

A. negatively by depleting soil organic matter and weakening soil structure

B. positively by physically repturing dense soil aggregates

C. positively by bringing looser soil found at lower depths to the surface.

D. negatively by mixing surface residues into the plow layer

Answer 2

A. negatively by depleting soil organic matter and weakening soil structure

Question 3

Generally, cultivation has which of the following impacts on bulk density (Db) and total porosity (TP): (L.O. 39)

a.
increases both
b.
decreases both
c.
increases Db, but reduces TP
d.
decreases Db, but increases TP.

Answer 3

c.
increases Db, but reduces TP

Question 4

Conservation tillage may be useful for prevention of or remediation of soil crusting because it ( L.O. 36)

a.
stimulates a breakdown of the soil aggregates that cause crusting
b.
enhances residue cover on the soil surface thus minimizing the impact of raindrops and accumulated soil organic matter levels promote good infiltration
c.
keeps soil temperatures cooler thus preventing fusion of soil particles
d.
positions seeds in such a way that they can break through a soil crust.

Answer 4

b.
enhances residue cover on the soil surface thus minimizing the impact of raindrops and accumulated soil organic matter levels promote good infiltration

Question 5

Which of the following guidelines is NOT good advice for promoting soil tilth? ( L.O. 37)
a.
Mulching soils can encourage earthworm activity
b.
Applying composts can stimulate decomposition
c.
Adding gypsum can stabilize soil aggregates
d.
Plowing can increase soil organic matter.

Answer 5

d.
Plowing can increase soil organic matter.

Question 6

The physical condition of the soil in relation to plant growth is referred to as: (L.O. 37)

a.
structure
b.
tilth
c.
aggregation
d.
regolith.

Answer 6

b.
tilth

Question 7

Aggregate formation begins with ( L.O. 32, 33)

a. weathering of primary minerals to form secondary minerals.

b .flocculation of clay particles.

c. swelling and shrinking of clay masses.
d. tilling a soil.

Answer 7

b.
flocculation of clay particles.

Question 8

You collect 200 cm 3 of a soil that has a particle density of 2.70 g/cm 3. After drying for 48 hours at 105 C the mass of the soil collected is 264 g. Using this information, find the percent pore space of this soil. ( L.O. 42)

a.
35. 4%
b.
47. 2%
c.
51. 1%
d.
65. 5%

Answer 8

c.
51.1%

Question 9

In comparison to macropores, soil micropores are (L.O. 41)

a.
quickly drained of water

b.
sources of plant nutrients

c.
large enough to permit earthworms

d.
poorly aerated.

Answer 9

d.
poorly aerated.

Question 10

Macropores are best characterized by: (L.O. 41)

a.
preventing the entry of plant roots.
b.
inhibiting the movement of water and air.
c.
allowing the movement of water and air.
d.
their size, which is smaller than 0.08mm.

Answer 10

c.
allowing the movement of water and air.

Question 11

This important property of the water molecule itself gives rise to almost all of the other properties of water as a substance: (LO 43)
a.
surface tension
b.
adhesion
c.
polarity
d.
cohesion

Answer 11

c.
polarity

Question 12

In which of the following soils would water (supplied to the bottom of a soil column) rise the highest ultimately (at long times)? (LO 45)
a.
loamy sand
b.
silt loam
c.
sand
d.
clay loam

Answer 12

d.
clay loam

Question 13

The attraction of water to solid surfaces gives rise to its __________ potential. (LO 46)
a.
osmotic
b.
kinetic
c.
matric
d.
gravitational

Answer 13

c.
matric

Question 14

At 0 bars of soil water potential, _____ soils hold the most water; at -10 bars of pressure, _____ soils hold the most water. (LO 47)

a.

clay, clay

b.

clay, sand

c.

sand, clay

d.

sand, sand

Answer 14

a.

clay, clay

Question 15

“Saturated hydraulic conductivity” in soil systems refers to: (LO 49)

a.

rate of movement of pesticide downward in a soil profile

b.

rate of movement of water downward in a soil profile

c.

evaporative loss of water from soil surfaces under warm, dry air conditions

d.

horizontal movement of water across a landscape, under the soil surface

Answer 15

b.

rate of movement of water downward in a soil profile

Question 16

Based on Table 5.5, which horizon in this Ultisol had the highest K_sat? (LO 49)

a.

Ap

b.

E

c.

E/B

d.

Bt, uppermost

Answer 16

a.

Ap

Question 17

High Ksat values can help protect topsoils by reducing runoff of incoming rainfall. Which of the soil management models presented in Figure 5.20 would therefore be the best way to protect topsoils? (LO 50)

a.

conventional tillage

b.

no-tillage

c.

native forest

d.

native grassland

Answer 17

c.

native forest

Question 18

Which of the following best expresses the rate of infiltration of water into an expanding clay (LO 52)?

a.

consistently rapid infiltration over time

b.

rapid infiltration at first, then moderate rates later

c.

rapid infiltration at first, then very slow rates later

d.

essentially no infiltration at any time.

Answer 18

c.

rapid infiltration at first, then very slow rates later

Question 19

According to Figure 5.35, the most plant available water would be found in soils with a ____________ textural class. (LO 55)

a.

sand

b.

sandy loam

c.

loam

d.

silt loam

e.

clay loam

f.

clay

Answer 19

d.

silt loam

Question 20

Which soil organic matter content would result in the highest field capacity? (LO 55)

a.

1 %

b.

2 %

c.

3 %

d.

4 %

e.

5 %

f.

6 %

Answer 20

f.

6 %

Question 21

In general, surface soil temperatures: (LO 74)

a.

vary more or less according to air temperatures

b.

do not vary with season

c.

do not vary with month of the year

d.

are consistently greater than subsoil temperatures

Answer 21

a.

vary more or less according to air temperatures

Question 22

The chemistry of hydric soils is characterized by: (LO 68)

a.

redoximorphic features in the upper soil horizons

b.

redoximorphic features in the lower soil horizons

c.

no redoximorphic features in soil

d.

no soil color changes

e.

all of the above

Answer 22

a.

redoximorphic features in the upper soil horizons

Question 23

Hydrophytic vegetation represents plants which can tolerate: (LO 68)

a.

other plants

b.

compaction

c.

high soil density

d.

presence of wildlife

e.

saturated, anaerobic soils

Answer 23

e.

saturated, anaerobic soils

Question 24

Select the best statement from Figure 7.21: (LO 69)

a.

air and soil temperature showed no effect on turf quality

b.

high air and soil temperature caused the greatest decline in turf quality

c.

high air and soil temperature caused the greatest improvement in turf quality

d.

all of the above

Answer 24

b.

high air and soil temperature caused the greatest decline in turf quality

Question 25

For a soil in a landscape to be declared a wetland, it must pass which of the following tests:(LO 68)

a.

the presence of wet, anaerobic soil conditions for some of the year

b.

soil showing reduced conditions, such as gley chroma

c.

plants known to favor wet conditions are found in the site

d.

all of the above

Answer 25

d.

all of the above

Question 26

Review Figure 7.22. Which one of the following statements is supported by the figure?(LO 69)

a.

“When soils were heated, broccoli harvest started later.”

b.

“When soils were heated, broccoli farmers made higher net profits.”

c.

“When soils were NOT heated, nutrional quality of the broccoli was higher.”

d.

“When soils were NOT heated, broccoli yields were much lower.”

Answer 26

d.

“When soils were NOT heated, broccoli yields were much lower.”

Question 27

Evaluate Figure 7.24 with respect to carbon respiration. Which statement is best supported by the data shown?(LO 70)

a.

“A 10 degree C increase in soil temperature doubles microbial respiration.”

b.

“Above 20 C, microbial respiration drops dramatically.”

c.

“Soil respiration is generally measured as oxygen release from soil systems.”

d.

“Microbial respiration is higher in wet soils than in dry soils.”

Answer 27

a.

“A 10 degree C increase in soil temperature doubles microbial respiration.”

Question 28

Study Figure 7.25. Frost heaving of an alfalfa plant is caused by: (LO 72)

a.

“Lenses of frozen water push the upper root upward.”

b.

“Lenses of frozen water push the lower root downward.”

c.

“When vertical cracks fill with frozen water, lateral roots snap.”

d.

“When vertical cracks fill with frozen water, vertical roots suffocate.”

Answer 28

a.

“Lenses of frozen water push the upper root upward.”

Question 29

Observe Figure 7.35. Which soil temperature scenario best matches the data shown? In August, mulched soils were ______ compared with non-mulched soils, while in January, mulched soils were ______ compared with non-mulched soils. (LO 73)

a.

cooler, cooler

b.

cooler, warmer

c.

warmer, cooler

d.

warmer, warmer

Answer 29

b.

cooler, warmer

Question 30

Figure 7.37 shows data about tillage and soil temperature. In June in northern British Columbia, Canada, which tillage system resulted in the highest mid-afternoon soil temperatures?(LO 75)

a.

conventional tillage

b.

modified conventional tillage

c.

no-tillage

d.

modified no-tillage

Answer 30

a.

conventional tillage

Question 31

(LO76) The underlying feature which is responsible for the adsorption of cations to most soil colloids is:

a.

surface area

b.

particle volume

c.

negative charges

d.

positive charges

Answer 31

c.

negative charges

Question 32

(LO77) The most likely substitute for Si⁴⁺ in tetrahedral sheets of silicate clays is:

a.

Al³⁺

b.

Fe³⁺

c.

Mg²⁺

d.

Zn²⁺

Answer 32

a.

Al³⁺

Question 33

(LO78) The most prominent member of the smectite family of 2:1 expanding clays is:

a.

kaolinite

b.

montmorillonite

c.

vermiculite

d.

chlorite

Answer 33

b.

montmorillonite

Question 34

(LO79) Human uses of kaolinitic clay have included:
a.
treatment for diarrhea
b.
control of fruit leaf pests
c.
space shuttle heat shielding
d.
porcelain pot manufacture
e.
all of the above.

Answer 34

e.
all of the above.

Question 35

(LO80) This aluminum oxide, found in highly weathered soils, can adsorb certain anions:
a.
pyrite
b.
goethite
c.
gibbsite
d.
kaolinite

Answer 35

c.
gibbsite

Question 36

(LO81) X-ray diffraction analysis of clay minerals gives us “d-spacing” values which can be used to:

a.

identify clay minerals present

b.

determine the textural class of the soil

c.

validate Stokes Law empirically

d.

pinpoint the buffer pH of the soil

Answer 36

a.

identify clay minerals present

Question 37

(LO83) Once a cation is released by a soil colloid, it can again be adsorbed to a soil colloid. This illustrates the cation exchange principle of:

a.

reversibility

b.

charge equivalence

c.

ratio law

d.

anion effects

e.

cation selectivity

f.

complementary cations

Answer 37

a.

reversibility

Question 38

(LO83) Based on this cation exchange principle, Al³⁺ is much more tightly held by soil cations than is K⁺:
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a.

reversibility

b.

charge equivalence

c.

ratio law

d.

anion effects

e.

cation selectivity

f.

complementary cations

Answer 38

e.

cation selectivity

Question 39

(LO85) Review Figure 8.22. What does this method allow us to learn about a soil?

a.

whether it has good soil tilth

b.

whether it has a high amount of plant available water

c.

how great its cation exchange capacity is

d.

how great its anion exchange capacity is

Answer 39

c.

how great its cation exchange capacity is

Question 40

(LO87) According to Figure 8.23, the type of clay with the highest cation exchange capacity is:

a.

micas

b.

vermiculites

c.

Fe oxides

d.

chlorites

e.

kaolinites

Answer 40

b.

vermiculites