Soil Science Exam 1
A soil pedon is ____
The smallest volume that can be called a soil
Which soil is a peat or bog, and has greater than 20% organic matter?
Histosols
The albic subsurface horizon is appropriately defined as:
Light coloured, leeched of clay, iron, and aluminum
Argillic horizons are characterized by ___
accumulation of silicate clays
As temperature increases and abundant water is available soil formation will:
increase
Peat and muck soils develop from _____ that decomposed incompletely after being deposited in water.
organic materials
In a typical mineral soil in optimal condition for plant growth, approximately what percentage of the soil would be filled with water and what percentage filled with air?
20-30 percent water, 20-30 percent air
A soil polypedon is defined as:
A group of pedons, which is of significant size to be recognised as a soil individual
The kandic subsurface horizon is appropriately defined as:
Accumulation of low activity clays
The calcic subsurface horizon is appropriately defined as:
Accumulations of calcium and/or magnesium
Acid Reactions, a chemical weathering reaction, is best described as _________
Acid breaking apart molecules faster
Hydration, a chemical weathering reaction, is best described as _________
Adding or combining water
Silt-size particles deposited by wind are called _____
Aeolian
Which soil can have an argillic, natric, or kandic horizon; high-to-medium base saturation, typically soil type in Appalachia?
Alfisols
A soil series is defined as:
All the soil individuals in the world that have in common a suite of soil profile properties and horizons that fall within a particular range
A(n) _______ develops at the mouth of narrow canyons in upland areas
Alluvial fan
Which soil moisture regime has the highest soil moisture levels?
Aquic
The topographical feature that describes the direction that a slope faces with respect to the sun is called:
Aspect
Silicate clay accumulation is most common in the ____
B horizons
______ refers to the activity of animals on the soil development process.
Biopedoturbation
_______ weathering is involved in the synthesis of secondary minerals.
Chemical
The mixed angular gravel, rock, and soil found at the foot of a slope is typical of what type of parent material?
Colluvial
An alluvial deposit formed where a stream or river drops its sediment load upon entering a quieter body of water is most appropriately referred to as:
Delta
Mechanical or physical weathering processes result in:
Destruction and synthesis
Dissolution, a chemical weathering reaction, is best described as _________
Dissolving into water
In which soil orders would recent alluvium most likely be a common parent material?
Entisols
The land bordering a stream, built up of sediment from overflow of the stream and subject to inundation when the stream is at flood stage is most appropriately referred to as:
Flood plain
______ is a method of physical weathering that results from the expansion and contraction of rocks due to differences in daytime and nighttime temperature.
Freeze/Thaw
If the soils are to be used for crop production, for which soil order would land drainage be most critical
Histosols
The reaction: mica + H2O 🡪 K+ + OH- + acid clay is an example of ________
Hydrolysis
Which soil is beginning to have profile development with few diagnostic features, ochric or umbric epipedon, and a cambic horizon?
Inceptisols
The element most often involved in oxidation reactions as minerals weather is _____
Iron
Oxidation reduction, a chemical weathering reaction, is best described as _________
Losing an electron and becoming oxidized
Complexation, a chemical weathering reaction, is best described as _________
Mineral and organic molecules combine
Which soil has a high base saturation, dark soils, some with argillic or nitric horizons, and is very productive?
Mollisols
In the temperate regions of the northern hemisphere, which slope aspect would have soils with the highest soil organic matter?
North facing slopes
The spodic subsurface horizon is appropriately defined as:
Organic matter, accumulation of iron and aluminum oxides
Which of the following subsurface diagnostic horizons would you expect to find in a highly weathered soil of the humid tropics?
Oxic
Which of the following soil descriptions would be the most mature and possibly the oldest?
Oxisols
What are the five major factors influencing soil formation?
Parent material Climate Biota Topography Time
Hydrolysis, a chemical weathering reaction, is best described as ________
Removing or separating water
The Argillic subsurface horizon is appropriately defined as:
Silicate clay accumulation
The degree of deviation of a surface from horizontal, measured in numerical ratio, percent, or degrees is called:
Slope
Soils in this order are commonly sandy in texture, quite acidic and develop primarily under coniferous trees in cool to cold climates
Spodosols
The amount of different sizes of mineral particles in a soil defines the soil ________
Texture
"Topsoil" is generally equivalent to which soil horizon?
The A horizon
"Subsoil" is generally equivalent to which soil horizon?
The B horizon
Organic matter accumulation is most pronounced in the ____
The O horizon
A mollic epipedon is described as:
Thick, dark coloured, high saturation
An umbric epipedon is defined as:
Thick, dark coloured, low saturation
A soil has a thick black A horizon, a distinct B horizon, has reasonably stable soil structure, and was formed under grassland natural vegetation. In which suborder is it most likely classed?
Udolls
Which soil can be argillic or kandic horizon, low base saturation, located in Southeast U.S.A., and is a strong red color?
Ultisols
Describe a soil likely to contain a significant content of low activity clays.
Ultisols and/or Kandic
The natric subsurface horizon is appropriately defined as:
argillic, high in sodium
Which soil has the following characteristics: dry soil, ochric epipedon, sometimes argillic or natric horizon
aridisols
If you wanted to find a soil where physical weathering dominated over chemical breakdown you would be most apt to find it in ______
cold, dry environments
In which of the following epipedons is the organic matter level generally lowest?
ochric
Exfoliation is caused by changes in _________
temperature
A soil profile consists of ______
the set of layers seen in a vertical cross section of a soil
Soil occupies the ________ part of the regolith.
upper