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