Geosystems: An Introduction to Physical Geography, 9e (Christopherson)
Chapter 18 The Geography of Soils
18.1 Multiple Choice Questions
1) Which of the following best describes soil?
A) Soil is composed of solely mineral fragments less than 2 mm in size.
B) Soil lacks biological material.
C) Soil is a renewable resource.
D) Soil is a dynamic natural material composed of water, air, mineral fragments, and organic
matter.
2) The branch of soil science that deals with the origin, classification, distribution, and
description of soils is known as
A) pedology.
B) edaphology.
C) geology.
D) geomorphology.
3) The branch of soil science that studies soil as a medium for sustaining the growth of higher
plants is known as
A) pedology.
B) edaphology.
C) geology.
D) geomorphology.
4) Which of the following best describes the composition of soil?
A) Soil is primarily mineral matter (approximately 72%), but also consists of organic matter
(10%), and water (18%).
B) Soil consists of approximately 45% organic matter, 50% mineral matter, and 5% water and/or
air.
C) Soil is composed of about 45% mineral matter, 5% organic matter, and 50% pore space
containing air and water.
D) Soil includes pebbles, gravel, cobbles, and a varying combination of sands, silts, and clays.
5) Which of the following is not one of the five primary soil-forming factors?
A) topography
B) climate
C) human activity
D) biological activity
E) parent material
6) In regards to soil-formation, which of the following best describes the role of climate?
A) Because all soils are ancient, they show the climatic conditions of the period in which they
formed.
B) Of the five principle soil-forming factors, climate is the least significant with little correlation
between soil and climates worldwide.
C) Temperature and moisture determine the chemical reactions, organic activity, and water
movement within soils.
D) Relative humidity and atmospheric pressure are the dormant climatic factors that influence
soil development.
7) Which of the following best describes the role of biological activity in soils development?
A) Broadleaf trees tend to increase the alkalinity of soil, whereas needleleaf trees increase the
acidity.
B) Earthworms increase soil porosity and contribute to soil movement and organic content.
C) Plant roots provide channels for air and water movement in soils.
D) All organisms living in, on, and over the soil, influence soil development and characteristics:
they can influence the pH, the organic matter, chemical content, and biological content of soils.
8) Where would one likely find the deepest soil development?
A) on steep slopes
B) level or nearly level grounds
C) moderately sloping, south facing hills
D) over the oldest geological formations in an area, regardless of slope
9) Soils will develop at faster rates in which of the following environments?
A) hot and dry
B) cold and dry
C) warm and humid
D) in areas where they can develop directly from bedrock, regardless of climate conditions
10) A vertical cross section of soil extending from the surface to the deepest extent of plant root
activity or to the regolith and bedrock is known as a
A) pedon.
B) soil profile.
C) soil horizon.
D) polypedon.
11) The basic sampling unit, in soil surveys representing all the characteristics and variability
used for classification, is
A) soil profile.
B) pedon.
C) soil horizon.
D) polypedon.
12) A vertical section of soil is generally organized into distinct horizontal layers called
A) soil profiles.
B) pedons.
C) soil horizons.
D) polypedons.
13) Which of the following soil horizon designations is i the correct sequence from the surface to
the bedrock?
A) O, E, C, B, A
B) A, B, C, O, R
C) S, O, I, L
D) O, A, E, B, C
14) The organic rich horizon found at the top of the soil profile is the ________ horizon.
A) A
B) O
C) E
D) B
E) C
15) The horizon that is commonly called topsoil is the ________ horizon.
A) A
B) O
C) E
D) B
E) C
16) The horizon in which water moves fine particles downward in a process called eluviation is
the ________ horizon.
A) A
B) O
C) E
D) B
E) C
17) The horizon in which leached materials from other horizons is accumulated is the ________
horizon.
A) A
B) O
C) E
D) B
E) C
18) The horizon identified as regolith is the ________ horizon.
A) A
B) O
C) E
D) B
E) C
19) Which of the following is not a physical property used to distinguish soils?
A) color
B) texture
C) porosity
D) moisture
E) temperature
20) Which of the following is correct regarding the soil physical property of soil?
A) Dark soils always indicate high organic content.
B) Despite the imporantance of color in describing soils, there is no standard methods for
standardized descriptions.
C) Soil color is used solely to determine the moisture content of soil—darker soils have a higher
moisture content, whereas lighter soils have less water content.
D) Color reflects composition and chemical makeup of a soil.
21) Soil separates refers to
A) differing soil colors in a pedon.
B) individual mineral particles, such as sand, silt, and clay.
C) the different soil horizons.
D) pebbles, gravel, cobble, and other materials greater than 2 mm in diameter found in soils.
22) A roughly equal mix of sand, silt, and clay is called
A) humus.
B) regolith.
C) solum.
D) loam.
23)
A soil that is 20% sand, 60% silt, and 20% clay is classified as
A) sandy clay.
B) sandy clay loam.
C) silt loam.
D) clay loam.
24)
A soil that is 40% sand, 40% silt, and 20% clay is classified as
A) loam.
B) silty clay.
C) silt loam.
D) clay loam.
25) ________ refers to the size and shape of the aggregates of particles of soil.
A) Soil texture
B) Soil consistence
C) Soil structure
D) Soil plasticity
26) The smallest natural lump or cluster of soil particles is known as a
A) horizon.
B) ped.
C) profile.
D) separate.
27) Soil structure can be defined as which of the following?
A) crumb or granular
B) platy
C) blocky
D) prismatic
E) crumb or granular, platy, blocky, or prismatic are all type of soil structure
28) Rounded peds have ________ space between them than other peds, and are therefore
________ for plant growth.
A) less; better
B) less; worse
C) more; worse
D) more; better
29) Ped formation enhances
A) soil texture.
B) permeability.
C) soil horizons.
D) plasticity.
30) In soil science, the term to describe the cohesion of soil particles is
A) soil texture.
B) permeability.
C) consistence.
D) soil structure.
31) The term used to denote the part of a volume of soil that is filled with air, gases, or water is
A) soil texture.
B) porosity.
C) permeability.
D) soil structure.
32) A plant that is unable to extract needed water from soil has reached its
A) field capacity.
B) permeability.
C) wilting point.
D) porosity.
33) Carbon dioxide concentrations in soil are ________ than in the atmosphere because
________.
A) lower; transpiration
B) lower; plant photosynthesis
C) higher; ongoing respiration in the ground
D) higher; decay of dead plants and animals
34) Why is cation-exchange capacity (CEC) an important soil characteristic?
A) CEC is an indication of the soil permeability; the lower the CEC the higher the permeability.
B) CEC is a measure of soil fertility; the higher the CEC the higher the soil fertility.
C) CEC is an indirect way to measure soil pH; it indicates whether the soil is neutral, alkaline, or
acidic.
D) CEC is used to infer soil texture without having to use a soil texture triangle.
35) Acidic soils
A) are exceptionally rare.
B) cause more rapid weathering and leaching of nutrients.
C) tend to be very fertile and excellent for agriculture purposes.
D) are high in calcium, magnesium, potassium, and sodium ions.
36) A few centimeters’ thickness of prime farmland soil may require ________ years to form.
A) 10
B) 50
C) 100
D) 500
37) Which of the following human activities may make soils more prone to erosion?
A) overcultivation
B) overgrazing
C) forest clearance
D) overcultivation, overgrazing,and forest clearance may all make soils more prone to erosion
38) The practice of leaving crop residue on the field between plantings to help prevent soil
erosion is known as
A) slash and burn agriculture.
B) swidden.
C) shifting cultivation.
D) no-till agriculture.
39) The multiyear period of severe wind erosion and soil loss occurred in the Great Plains during
the 1930s is known as
A) desertification.
B) the Grapes of Wrath.
C) the Black Blizzard.
D) the Dust Bowl.
40) Between 1982 and 2007, soil erosion on U.S. cropland
A) decreased by 43%.
B) increased by 25%
C) increased by 13%.
D) decreased by 21%.
41) The phenomenon of desert expansion along the margins of semiarid and arid lands is known
as
A) deflation.
B) desertification.
C) erosion.
D) permeability.
42) Worldwide, desertification is affecting an estimated ________ people.
A) 100,000
B) 1,000,000
C) 5,000,000
D) 1,000,000,000
43) Which of the following is not a factor contributing to desertification?
A) overgrazing
B) no-till agriculture
C) salinization
D) climate change
44)
Which of the following areas has the highest rick of desertification?
A) the Sahel (Sub-Saharan Africa)
B) northeastern Australia
C) central Asia
D) Venezuela
45) The lowest and most precise level of the U.S. soil classification system is
A) soil family.
B) soil order.
C) soil series.
D) soil group.
46) Which of the following is correct about the U.S. soil classification system?
A) Soil variation is too complex for a single classification system, so many regional
classification systems are used within the U.S.
B) The Soil Taxonomy is hierarchical, consisting of six categories from soil series to soil order.
C) The soil classification system was finalized in 1975 and no additional changes to it will be
made.
D) It is primarily based on pedogenic regimes in which each soil-forming process is attached to a
climatic region.
47) In terms of pedogenic regimes, the leaching process in humid and warm climates is known as
A) laterization
B) salinization.
C) calcification.
D) podzolization.
E) gleization.
48) Laterization is likely to occur
A) in the tropics.
B) in areas of high potential evapotranspiration rates.
C) in humid climate regions.
D) in areas characterized by sandy soils and coniferous forests.
49) In terms of pedogenic regimes, the process that concentrates salts in soils in climates with
high evapotranspiration is
A) laterization.
B) salinization.
C) calcification.
D) podzolization.
E) gleization.
50) Salinization is likely to occur
A) in the tropics.
B) in areas of high potential evapotranspiration rates.
C) in humid climate regions.
D) in areas characterized by coniferous forests.
51) In terms of pedogenic regimes, the process that produces an illuviated accumulation of
calcium carbonate in continental climates is
A) laterization
B) salinization.
C) calcification.
D) podzolization.
E) gleization.
52) Calcification is likely to occur
A) in areas with Vertisols.
B) in areas with Mollisols and Aridisols.
C) in tropical climate regions.
D) in areas characterized by coniferous forests.
53) In terms of pedogenic regimes, soil acidification associated with forest soils in cool climates
is
A) laterization.
B) salinization.
C) calcification.
D) podzolization.
E) gleization.
54) Podzolization is likely to occur
A) in the tropics.
B) in areas with broadleaf forests.
C) in humid climate regions.
D) in areas characterized coniferous forests.
55) In terms of pedogenic regimes, the process that results in an accumulation of humus
overlaying a thick, water saturated layer of clay in cold, wet climates with poor drainage
conditions is
A) laterization
B) salinization.
C) calcification.
D) podzolization.
E) gleization.
56) Which of the following is among the most mature soils on Earth?
A) Andisols
B) Inceptisols
C) Entisols
D) Oxisols
57) Oxisols have a ________ cation-exchange and, therefore, ________ fertility.
A) high; high
B) low; high
C) low; low
D) high; low