Question 1

Which soil horizon is known as the zone of accumulation?
A)A horizon
B)B horizon
C)C horizon
D)R horizon

Accepted Answer

The B horizon is known as the zone of accumulation because it is where leaching from the upper layers deposits minerals and organic materials, enriching this layer.

Question 2

Soil scientists and engineers view soil in essentially the same way.

Accepted Answer

Soil scientists and engineers view soil differently because their objectives and perspectives differ. Soil scientists focus on soil formation, classification, and mapping, studying its physical, chemical, and biological properties. Engineers, on the other hand, are primarily concerned with soil's mechanical properties, such as strength, stability, and suitability for construction projects.

Question 3

The A horizon of a soil is typically richer in organic matter than is the B horizon.

Accepted Answer

The A horizon is the top layer of soil and is often referred to as the topsoil. It is typically richer in organic matter and nutrients than the B horizon, which is the second layer of soil. The B horizon is usually less fertile and contains more mineral particles.

Question 4

The unified soil classification system, which is based on soil texture, is particularly useful for agricultural purposes.

Accepted Answer

The Unified Soil Classification System (USCS) is primarily used for engineering and geotechnical purposes rather than for agriculture, which often relies on soil texture classifications that focus more on soil fertility and management.

Question 5

Why was Times Beach, Missouri, evacuated in 1983?
A)Soils had eroded so deeply in a large rainstorm that streets were irreparably damaged.
B)Soils had become contaminated with dioxin.
C)Soils had become infertile because of excessive agricultural use.
D)Expansive soils damaged most of the buildings in town.

Accepted Answer

Times Beach, Missouri was evacuated in 1983 due to the contamination of soils with dioxin, a toxic chemical that can cause cancer and other health problems. The contamination was linked to the use of dioxin-containing oil to stabilize the town's dirt roads.

Question 6

Soil cohesion is enhanced by the presence of
A)gravel and sand particles
B)clay and silt particles
C)subsurface water
D)organic matter

Accepted Answer

Clay and silt particles have a higher surface area available for bonding with water molecules, creating stronger interparticle forces and increasing the soil cohesion.

Question 7

A sharp peak in sediment yield in the Piedmont region around 1960 corresponded with a period of
A)conversion of land to agriculture
B)extensive off-road vehicle use
C)heavy rainfall
D)rapid urbanization

Accepted Answer

The sharp peak in sediment yield in the Piedmont region around 1960 corresponds with a period of rapid urbanization, which leads to increased runoff and erosion due to the replacement of vegetation with impervious surfaces such as buildings and roads.

Question 8

How do soils become fertile?
A)deep and thorough leaching of parent material to release nutrients
B)mild weathering of parent material and addition of organic matter
C)human manipulation to retain moisture and improve texture
D)intimate interaction with the soil biota

Accepted Answer

Mild weathering of parent material and the addition of organic matter are the primary mechanisms for soil becoming fertile. As the parent material weathers, minerals are broken down into smaller particles, which can provide nutrients for plants. Additionally, organic matter such as plant debris and animal waste can add nutrients and improve soil structure, allowing for better water retention and root development.

Question 9

Shrink-swell potential of a soil is dependent upon
A)the hydraulic conductivity of the soil
B)the proportion of clay in the soil
C)the proportion of fine sand in the soil
D)the chemistry and water content of the soil

Accepted Answer

The shrink-swell potential of a soil is primarily dependent upon the proportion of clay in the soil. Clay particles have a high surface area relative to their volume and are able to hold onto water molecules tightly. When the soil dries out, the clay particles contract and cause the soil to shrink. When the soil becomes wet again, the clay particles expand, causing the soil to swell. Soils with high proportions of clay are more prone to shrink-swell behavior. However, it should be noted that other factors such as chemistry and water content can also influence the shrink-swell potential of a soil.

Question 10

Soil fertility depends primarily on bedrock type.

Accepted Answer

While bedrock type can have some influence on soil fertility, other factors such as climate, topography, vegetation, and human activities (such as agriculture or mining) can have a greater impact. Soil fertility is also influenced by factors such as the mineral content, organic matter content, and pH of the soil.

Question 11

Clay soils tend to resist deformation because clays have high cohesion and high intra-grain friction.

Accepted Answer

Clay soils tend to resist deformation primarily due to their high cohesion, but they actually have low intra-grain friction compared to sandy soils.

Question 12

In what ways are soil surveys useful for land-use planning?
A)They provide the basis for rating limitations for specific land uses.
B)They provide maps showing the shrink-swell potential of soils.
C)They provide the basis for determining land valuation.
D)They show where existing soils have been covered by urbanization.

Accepted Answer

Soil surveys are useful for land-use planning because they provide the basis for rating limitations for specific land uses. By understanding the characteristics of the soil, such as its texture, depth, and drainage, planners can make informed decisions about what types of land uses are appropriate for a particular area. For example, a soil survey may indicate that the soil in a certain area is prone to erosion, which would make it unsuitable for agriculture or development. Alternatively, a soil survey may identify areas with deep, fertile soils that would be suitable for farming or forestry. By using this information, planners can ensure that land use is compatible with the soil's characteristics and avoid problems such as erosion, flooding, and soil compaction.

Question 13

What is hydraulic conductivity?
A)the velocity at which water passes through soil
B)the proportion of sand and gravel in a soil
C)the number and sizes of pore spaces in a soil
D)the ability of a porous material to transmit water

Accepted Answer

Hydraulic conductivity is the ability of a porous material (such as soil) to transmit water. It is affected by factors such as the size and connectivity of pore spaces, as well as the properties of the water itself. Options A, B, and C are related to factors that can affect hydraulic conductivity, but they are not the definition of hydraulic conductivity itself.

Question 14

The principal advantage of the Universal Soil Loss Equation is
A)ease of use and ability to evaluate the potential impact of conservation practices
B)rapid estimation of soil erosion at every location in a site of interest
C)ready estimation of reservoir siltation
D)prediction of the amount of nutrient loading in a stream adjacent a farm field

Accepted Answer

The Universal Soil Loss Equation (USLE) is designed to estimate soil loss caused by erosion on agricultural land. Its principal advantage is its ease of use and ability to evaluate the potential impact of conservation practices. This equation takes into account factors such as soil type, slope, rainfall, land management practices, cropping systems, and erosion control measures. By using USLE, farmers, land managers, and policymakers can assess the impact of different types of land use and evaluate the effectiveness of conservation practices in reducing soil erosion.

Question 15

Weathered material that remains in its place of formation is called
A)residual soil
B)transported soil
C)expansive soil
D)horizontal soil

Accepted Answer

Residual soil is formed by the weathering of rock in its place of origin and remains in that location. Transported soil, on the other hand, is moved from its place of formation by erosion, gravity, or water. Expansive soil refers to soil that swells and contracts due to changes in moisture content, and horizontal soil is not a recognized category of soil.

Question 16

In what way is color an indicator of soil drainage?
A)Well-drained soils tend to be well aerated and red in color.
B)Poorly drained soils tend to be well oxidized and red in color.
C)Moderately drained soils tend to be green in color.
D)Colors of soils are more reflective of organic matter than of drainage.

Accepted Answer

Well-drained soils tend to have good aeration, which encourages the presence of iron oxides. Iron oxides give soils a reddish color. So, well-drained soil tends to be red in color.

Answer: B
 Poorly drained soils tend to be boggy or waterlogged, which reduces the amount of oxygen present in the soil. This leads to poorly oxidized soils, which tend to be red in color.

Answer: D
 While soil color can provide some indications of the drainage status, other factors like the organic matter content of the soil can also influence soil color. Therefore, color alone cannot always be used as a reliable indicator of soil drainage.

Question 17

Off-road vehicle use contributes to soil problems by
A)loosening soil and changing the hydrology of a site
B)polluting soil with vehicle emissions
C)changing the local rainfall characteristics
D)changing the classification of a soil

Accepted Answer

Off-road vehicles can loosen soil and change the hydrology of a site by creating ruts and altering the topography, reducing infiltration and increasing erosion. This can lead to soil compaction, loss of soil structure, and decreased soil fertility. Additionally, the acceleration and deceleration of off-road vehicles can cause soil disturbance, displacement, and sedimentation. However, off-road vehicles do not necessarily pollute soil with emissions, change the local rainfall characteristics, or change the classification of a soil.

Question 18

How do engineers define soil?
A)solid Earth material that has been altered by physical, chemical, and biological processes
B)solid Earth material strong enough to support structures
C)solid Earth material that can be removed without blasting
D)solid Earth material that is generally fertile

Accepted Answer

The answer of How do engineers define soil?
A)solid Earth material...

Question 19

Urbanization influences soil erosion processes primarily because of
A)increased runoff from impermeable surfaces
B)increased soil pollution from street runoff
C)vegetation removal and soil disturbance at construction sites
D)desiccation of soils through draining and pumping of water

Accepted Answer

Urbanization often involves construction activities that remove vegetation, disturb soil, and increase soil erosion. This is because vegetation helps to hold the soil in place, and disturbed or exposed soil is more vulnerable to erosion by wind and water. Additionally, construction sites often involve grading and excavation, which can alter the natural drainage patterns and increase runoff, further exacerbating erosion. Pollution from street runoff and desiccation of soils through draining and pumping of water may also occur, but they are not the primary factors influencing soil erosion in urban areas.

Question 20

Soil taxonomy is a classification system based on
A)the processes that formed different soils
B)physical and chemical properties of the soil profile
C)divisions and subdivisions of soil texture
D)the organic matter content of the B horizon

Accepted Answer

Soil taxonomy is a classification system based on the physical and chemical properties of the soil profile, such as texture, structure, organic matter content, and mineralogy. This system classifies soils based on their unique characteristics, which can help in identifying and interpreting soil properties, soil formation processes, and soil management practices.

Quiz 17: Soils and Environment

Which soil horizon is known as the zone of accumulation?

Soil scientists and engineers view soil in essentially the same way.

The A horizon of a soil is typically richer in organic matter than is the B horizon.

The unified soil classification system, which is based on soil texture, is particularly useful for agricultural purposes.

Why was Times Beach, Missouri, evacuated in 1983?

Soil cohesion is enhanced by the presence of

A sharp peak in sediment yield in the Piedmont region around 1960 corresponded with a period of

How do soils become fertile?

Shrink-swell potential of a soil is dependent upon

Soil fertility depends primarily on bedrock type.

Clay soils tend to resist deformation because clays have high cohesion and high intra-grain friction.

In what ways are soil surveys useful for land-use planning?

What is hydraulic conductivity?

The principal advantage of the Universal Soil Loss Equation is

Weathered material that remains in its place of formation is called

In what way is color an indicator of soil drainage?

Off-road vehicle use contributes to soil problems by

How do engineers define soil?

Urbanization influences soil erosion processes primarily because of

Soil taxonomy is a classification system based on