Question 1

Which of the following explains why clay-rich soils are less permeable than sandy soils?

Accepted Answer

A)  clay particles are electrically charged and very small. 
B)  clay soils have greater porosity. 
C)  sandy soils have greater vegetation cover. 
D)  sandy soils tend to form in areas with abundant rainfall. 
E)  pores spaces of clay soils become plugged with sand grains. A

Question 2

Soil scientists and engineers classify soils differently. What best describes the basis for how engineers classify soils?

Accepted Answer

A)  physical properties 
B)  soil-forming factors 
C)  geographic location 
D)  thickness and density 
E)  water content A

Question 3

Which of the following best describes soil texture?

Accepted Answer

A)  the proportion of sand, silt, and clay particles 
B)  the number of fractures that develop when a soil becomes dry 
C)  whether a soil is pebbly or sandy 
D)  whether a soil is rough or smooth 
E)  the relative amounts of air and water A

Question 4

Quartz readily undergoes chemical weathering to form aluminum-rich clay minerals.

Accepted Answer

A) True 
 B)False

Question 5

A paleosol represents a soil profile that was buried under new sediment. What explains why paleosols are important in environmental geology?

Accepted Answer

A)  represent a distinct, datable time event 
B)  helps geologist locate coal deposits 
C)  provide valuable clues in the study of archaeology 
D)  are particularly well-drained 
E)  organic content is much higher than normal topsoil

Question 6

What explains why the soil property known as ion exchange is important in environmental geology?

Accepted Answer

A)  makes soils fertile by allowing them to store nutrients 
B)  reduces soil erosion in sandy soils 
C)  causes farmers to use more chemicals to control weeds 
D)  leads to the buildup of salts within a soil 
E)  causes soils to compact more easily

Question 7

What would you expect to see when digging vertically downward in a mature soil?

Accepted Answer

A)  horizons of different colors, textures, and composition 
B)  progressively thicker soil horizons 
C)  progressively coarser soil horizons 
D)  uniformly rich, fertile soil 
E)  alternating horizons of soil and rock

Question 8

Which of the following is an effective technique for reducing soil erosion?

Accepted Answer

A)  all of the answers listed here 
B)  no-till farming 
C)  strip cropping 
D)  contour plowing 
E)  terracing

Question 9

Which of the following will cause soils to appear bright red or yellow?

Accepted Answer

A)  iron oxide minerals 
B)  quartz minerals 
C)  organic material 
D)  clay minerals 
E)  all of the answers listed here

Question 10

What explains why the soil property known as shrink-swell is important in environmental geology?

Accepted Answer

A)  causes structural damage in buildings 
B)  greatly enhances the effect of agricultural droughts 
C)  causes soils to become less permeable 
D)  causes soils to become unstable on steep slopes 
E)  prevents farmers from working their fields

Question 11

Which of the following describes why soils are important in environmental geology?

Accepted Answer

A)  soil loss will affect our ability to grow food as the population increases. 
B)  soil pollution is causing dangerous toxins to enter the food supply. 
C)  soil erosion worldwide is contributing to sea level rise. 
D)  soil erosion is affecting the hydrologic cycle and contributing to climate change. 
E)  all of the answers listed here.

Question 12

What best describes the basic way in which soils form?

Accepted Answer

A)  physical and chemical weathering of rock 
B)  erosion and deposition of sediment 
C)  breakdown of minerals by ultraviolet radiation 
D)  repeated flooding over long periods of time 
E)  reactions between water and atmospheric oxygen

Question 13

The O horizon, which is found only in some soil profiles, is an oxygen-rich layer.

Accepted Answer

A) True 
 B)False

Question 14

Salinization refers to the process where agricultural fields become unusable because of saline water in the soil root zone. What is the basic reason the water becomes too saline?

Accepted Answer

A)  irrigation water applied to the fields dissolves salt crystals within the soil 
B)  use of saline water to irrigate crops builds up salts over time 
C)  plant growth gives off ions, but the salts can't be flushed from the soil 
D)  ion exchange between rainwater and organic matter in the soil 
E)  all of the answers listed here

Question 15

The problem known as sediment pollution is a major environmental issue. Which of the following is a problem associated with sediment pollution?

Accepted Answer

A)  excess sediment in stream channels increases flooding 
B)  too much fertilizer makes soils toxic and unusable 
C)  buildup of heavy metals makes soils toxic and unusable 
D)  compaction reduces crop production 
E)  any pollution that causes crops to become unfit to eat

Question 16

Porosity is the term that describes the amount of void space within a material. What explains why porosity is important with respect to soils?

Accepted Answer

A)  provides plant roots access to moisture and oxygen 
B)  makes soils less compactable 
C)  reduces the ability of erosion to strip away topsoil 
D)  provides space for the breakdown of aluminum minerals 
E)  allows iron oxides to accumulate

Question 17

Which of the following statements best describes how time impacts soil formation?

Accepted Answer

A)  over time, more distinct soil horizons will form, each with their own characteristics. 
B)  over time, a soil will become more homogenous. 
C)  over time, more clay minerals accumulate in the uppermost layer to form topsoil. 
D)  over time, soils become enriched with air and water. 
E)  time does not impact soil formation.

Question 18

Which of the following best describes the root cause of soil loss?

Accepted Answer

A)  removal of natural vegetation 
B)  farmers applying too much fertilizer 
C)  farmers plowing their fields when wet 
D)  fields becoming too dry 
E)  climate change

Question 19

What describes how topsoil, or A-horizons develop?

Accepted Answer

A)  accumulation of organic matter in the upper soil zone 
B)  clay particles carried downward by infiltrating water 
C)  clay particles that are pulled upwards by plant roots 
D)  repeated flooding over long periods of time 
E)  reactions between water and atmospheric oxygen

Question 20

The topography of the landscape is an important soil forming factor. What topsoil characteristics would you expect to find on a topographic high?

Accepted Answer

A)  well drained and relatively thin 
B)  poorly drained and relatively thick 
C)  iron oxide rich and poorly drained 
D)  iron oxide poor and well drained 
E)  heavily vegetated and well drained

Exam 10: Soil Resources