PLS 366 ONLINE QUIZZES UP TO EXAM 3
An accumulation of silicate
clays in this horizon is labeled
with a subscript "t" - Answers -b horizon
Soil temps are generally ____ at the surface of no-tillage soil when
compared with plow tillage. - Answers -Cooler
On a hot summer day in July, you would expect the soil temperature
of the subsoil to be ______ than the surface soil - Answers -Cooler
The composition of soil air differs from that of the
atmosphere by containing more: - Answers -Carbon dioxide
What is the range in soil water potential which defines the
water that is available for plant uptake? - Answers -Wilting point and Field Capacity
(-1500 kPa) (-33 kPa)
How do you interpret the trends in Ksat data with soil depth? - Answers -Coarser-
textured surface contains more
macropores, resulting in greater Ksat values.
Clay accumulation with soil depth, greater
micropore space, slows water movement
This soil textural class experiences the highest capillary rise ultimately - Answers -Clay
Name the components of total soil water potential that are governing
water movement in the figures (a and b) below - Answers -Matric potential
Gravitational potential
In general, surface soil temperatures (LO#74): - Answers -vary more or less according
to air temperatures
The chemistry of hydric soils is characterized by: (LO#68) - Answers -redoximorphic
features in upper soil horizons
Hydrophytic vegetation represents plants which can tolerate (LO#68): - Answers -
saturated, anaerobic soils
For a soil in a landscape to be declared a wetland, it must pass which of the following
tests? (LO#68) - Answers -the presence of wet, anaerobic soil conditions for some of
the year
soil showing reduced conditions, such as gley chroma
plants known to favor wet conditions are found on the site
, Wet soils would warm _______ _________ in the spring than dry soils (LO#69) -
Answers -more slowly
Where soil temperatures were measured in different tillage systems, which tillage
system resulted in coolest soil temperatures? (LO#75) - Answers -no-tillage
How is microbial respiration (measured as carbon dioxide release) affected by soil
temperature? (LO#71) - Answers -For every 10 degree C increase in soil temperature,
a doubling in respiration occurred
What is an important difference between soil air and atmospheric air (LO#62)? -
Answers -more carbon dioxide in the soil air
A soil with a red color indicates which of the following? (LO#63) - Answers -well drained
soil
Which of the following is not a factor influencing soil aeration? (LO#61) - Answers -The
presence of helium
Below this level, most plants cannot extract water from soils: (LO#54) - Answers -
permanent wilting point
Water flow from a fine textured silt loam layer to an underlying coarser textured sand
layer would be (#LO53): - Answers -slow
Key factor(s) in soil aggregation include: (LO#33) - Answers --attraction between
negatively charged clay particles
-shrinking and swelling of certain types of clays
-the amount of organic matter present in a soil
Give a soil with a bulk density of 1.22 g/cm3 and assuming a particle density of 2.65
g/cm3, what is the percent porosity? (LO#42) - Answers -54%
Which of the following soils would hold the most plant available water? (LO#55) -
Answers -silt loam
The explanation for why water "sticks" to solid surfaces is: (LO#44) - Answers -
adhesion
The component of soil water potential most closely related to capillarity is: (LO#47) -
Answers -matric
When water is applied to a silt loam topsoil over a sandy subsoil, a wetting front moves
down through the topsoil. What happens to the water when it reaches the sandy
An accumulation of silicate
clays in this horizon is labeled
with a subscript "t" - Answers -b horizon
Soil temps are generally ____ at the surface of no-tillage soil when
compared with plow tillage. - Answers -Cooler
On a hot summer day in July, you would expect the soil temperature
of the subsoil to be ______ than the surface soil - Answers -Cooler
The composition of soil air differs from that of the
atmosphere by containing more: - Answers -Carbon dioxide
What is the range in soil water potential which defines the
water that is available for plant uptake? - Answers -Wilting point and Field Capacity
(-1500 kPa) (-33 kPa)
How do you interpret the trends in Ksat data with soil depth? - Answers -Coarser-
textured surface contains more
macropores, resulting in greater Ksat values.
Clay accumulation with soil depth, greater
micropore space, slows water movement
This soil textural class experiences the highest capillary rise ultimately - Answers -Clay
Name the components of total soil water potential that are governing
water movement in the figures (a and b) below - Answers -Matric potential
Gravitational potential
In general, surface soil temperatures (LO#74): - Answers -vary more or less according
to air temperatures
The chemistry of hydric soils is characterized by: (LO#68) - Answers -redoximorphic
features in upper soil horizons
Hydrophytic vegetation represents plants which can tolerate (LO#68): - Answers -
saturated, anaerobic soils
For a soil in a landscape to be declared a wetland, it must pass which of the following
tests? (LO#68) - Answers -the presence of wet, anaerobic soil conditions for some of
the year
soil showing reduced conditions, such as gley chroma
plants known to favor wet conditions are found on the site
, Wet soils would warm _______ _________ in the spring than dry soils (LO#69) -
Answers -more slowly
Where soil temperatures were measured in different tillage systems, which tillage
system resulted in coolest soil temperatures? (LO#75) - Answers -no-tillage
How is microbial respiration (measured as carbon dioxide release) affected by soil
temperature? (LO#71) - Answers -For every 10 degree C increase in soil temperature,
a doubling in respiration occurred
What is an important difference between soil air and atmospheric air (LO#62)? -
Answers -more carbon dioxide in the soil air
A soil with a red color indicates which of the following? (LO#63) - Answers -well drained
soil
Which of the following is not a factor influencing soil aeration? (LO#61) - Answers -The
presence of helium
Below this level, most plants cannot extract water from soils: (LO#54) - Answers -
permanent wilting point
Water flow from a fine textured silt loam layer to an underlying coarser textured sand
layer would be (#LO53): - Answers -slow
Key factor(s) in soil aggregation include: (LO#33) - Answers --attraction between
negatively charged clay particles
-shrinking and swelling of certain types of clays
-the amount of organic matter present in a soil
Give a soil with a bulk density of 1.22 g/cm3 and assuming a particle density of 2.65
g/cm3, what is the percent porosity? (LO#42) - Answers -54%
Which of the following soils would hold the most plant available water? (LO#55) -
Answers -silt loam
The explanation for why water "sticks" to solid surfaces is: (LO#44) - Answers -
adhesion
The component of soil water potential most closely related to capillarity is: (LO#47) -
Answers -matric
When water is applied to a silt loam topsoil over a sandy subsoil, a wetting front moves
down through the topsoil. What happens to the water when it reaches the sandy
