Deck 15: The Geography of Soils

Question 1

Farmers are concerned with soil from the standpoint of

A) geomorphology.
B) pedology.
C) edaphology.
D) plantology.

Answer 1

C

Question 2

The surface of the Moon is covered with loose rock debris and fine particles. Given this, and what you know about the Moon, the surface material

A) could be considered a soil because regolith is present.
B) could be considered a soil because physical weathering processes occur.
C) could not be considered a soil because no organic matter is present and no organic processes occur.
D) both A and B

Answer 2

C

Question 3

What material in the soil serves a similar role to that of clay because of its ion exchange capacity, ability to store water, and ability to bind particles together?

A) calcium carbonate
B) humus
C) caliche
D) plinthite

Answer 3

B

Question 4

The A horizon is usually ________ underlying layers because ________.

A) darker than; it is made of dark-colored, mafic minerals
B) darker than; it contains humus
C) lighter than; it is made of light-colored, felsic minerals
D) lighter than; it contains little humus, but a considerable amount of mineral particles

Question 5

Which of the following is false regarding soils?

A) They usually require centuries or millennia to form.
B) Their development is affected by climate and organisms.
C) Their properties are affected by the type of rock from which they form.
D) Older soils usually have fewer horizons than younger soils.
E) Soils rich in organic matter are usually dark in color.

Question 6

The E horizon is dominated by ________, whereas the B horizon is dominated by ________.

A) eluviation; illuviation
B) eluviation; podzolation
C) illuviation; eluviation
D) laterization; illuviation

Question 7

A soil horizon that is 20 to 30 percent or more organic matter is labeled

A) A.
B) B.
C) C.
D) O.

Question 8

A pedon is imagined as

A) a soil profile.
B) a hexagonal column encompassing from 1 m² to 10 m² in surface area.
C) a basic sampling unit in soil surveys.
D) All of these are correct.

Question 9

The basic sampling unit in soil surveys is called

A) a polypedon.
B) a pedon.
C) the A horizon.
D) a horizon.

Question 10

A mixture of decomposed organic matter in soil that is usually dark in color is called

A) regolith.
B) polypedon.
C) humus.
D) mineral matter.

Question 11

As with many areas of interest to geographers, soil science is a/n ________ concerned with ________.

A) sharply limited and defined subject; memorization of facts about Earth
B) sharply limited and defined subject; spatial distributions and processes
C) multidisciplinary subject; memorization of facts about Earth
D) multidisciplinary subject; spatial distributions and processes

Question 12

Horizons develop in soil because of

A) leaching.
B) capillary action.
C) eluviation and illuviation.
D) all of the above
E) None of the above-the parent material is already layered at the time soil formation begins and all subsequent development involves only chemical transformation within the pre-existent horizons.

Question 13

If humus were lost from the soil due to excessive farming or soil erosion, which of the following could occur?

A) loss of soil structure
B) loss of fertility
C) loss of water holding capacity
D) all of the above
E) A and B only

Question 14

The basic soil unit used in preparing soils maps, i.e., in identifying a series of soils in an area, is the

A) polypedon.
B) profile.
C) A horizon.
D) pedon.

Question 15

The science that deals with the origin, classification, and distribution of soils is known as ________, whereas the science that deals with soil as a medium for plant growth is called ________.

A) pedology; edaphology
B) edaphology; pedology
C) pedology; geomorphology
D) geomorphology; edaphology

Question 16

The general name for any distinct layer in a pedon is

A) plate.
B) eluviation zone.
C) illuviation zone.
D) horizon.

Question 17

Which of the following is correct regarding soil?

A) Soil is an inorganic by-product of geological processes.
B) Soil is composed of mineral matter only.
C) Soil is a dynamic natural body composed of both mineral and organic matter.
D) Soil science is called geomorphology.

Question 18

Soil is

A) a physical, geological product.
B) ground-up rock.
C) a dynamic, natural body.
D) composed only of mineral particles.

Question 19

Which of the following soil horizon designations is in correct sequence from the surface to bedrock?

A) O, R, C, B, A
B) A, B, C, O, R
C) S, O, I, L
D) O, A, E, B, C, R

Question 20

The physical and chemical weathering of the upper lithosphere produces

A) soil.
B) materials from which soils can develop.
C) true soil with no further organic activity.
D) soil fertility.

Question 21

Rounded peds have ________ space between them than other peds, and are therefore ________.

A) less; worse for plant growth
B) less; better for plant growth
C) more; worse for plant growth
D) more; better for plant growth

Question 22

Which of the following sets of descriptors is correctly matched with the soil moisture condition indicated?

A) wet - little adherence of particles; capable of being rolled into a thin strand
B) moist - friable; firm
C) dry - loose; soft; hard; extremely hard
D) All of the above are correctly matched.

Question 23

Which of the following is false regarding the C horizon?

A) It is equivalent to regolith.
B) It lacks clay concentrations.
C) It is generally made up of carbonates, gypsum, or soluble salts.
D) Although it may be deep, it lies within the realm of significant biological influences.
E) Roots rarely reach this layer.

Question 24

White to pale hues in soils are generally associated with

A) iron oxides.
B) silicates and aluminum oxides.
C) humus.
D) plant matter.

Question 25

An individual unit of soil aggregates (a lump of soil) is termed a

A) solum.
B) separate.
C) pedon.
D) ped.

Question 26

Oxidation of minerals in the B horizon produces

A) red and yellow colors.
B) white colors.
C) black colors.
D) blue-gray colors.

Question 27

A cation has a ________ charge, and an anion has a ________ charge.

A) positive; negative
B) negative; positive
C) positive; neutral
D) neutral; positive

Question 28

The R horizon refers to

A) unweathered sediment or consolidated bedrock.
B) soils redeveloped through reclamation.
C) a zone of eluviation in the soil horizon.
D) the basic mapping unit of soils in an area.

Question 29

Weathered bedrock or weathered parent material (regolith), excluding the unweathered bedrock itself, is designated the ________ horizon.

A) A
B) B
C) C
D) R

Question 30

A roughly equal mixture of sand, silt, and clay is called

A) humus.
B) regolith.
C) solum.
D) loam.

Question 31

Texture refers to ________, whereas structure refers to ________.

A) soil particle size; the aggregation of soil particles into "dirt clods"
B) the aggregation of soil particles into "dirt clods"; soil particle size
C) soil fertility; soil productivity
D) soil productivity; soil fertility

Question 32

B horizons tend to

A) accumulate humus.
B) accumulate clay, iron and aluminum.
C) lose materials by leaching.
D) be dominated by eluviation processes.

Question 33

Which of the following is true of soil color?

A) Color does not reflect composition or chemical makeup.
B) Dark soils always indicate high organic content.
C) For consistency of description, a soil color chart is employed by soil scientists.
D) Soil color is restricted to the top horizon of the soil pedon.

Question 34

Soil consistency refers to

A) the uniformity of particle size.
B) the uniformity of ped types.
C) the soil's resistance to breaking and manipulation under different moisture conditions.
D) the soil's ability to consistently maintain a given level of soil moisture.

Question 35

Which of the following does not increase porosity?

A) worms
B) root growth
C) laterization
D) ped formation

Question 36

Ped formation benefits soils because it enhances

A) soil texture.
B) porosity.
C) permeability.
D) both B and C

Question 37

Soil separates refer to

A) differing soil colors in a pedon.
B) individual mineral particles, such as sand, silt, and clay.
C) the different soil horizons.
D) the larger pebbles, gravels, and cobbles.

Question 38

True solum is made up of

A) a combination of the A, E, and B horizons.
B) layers of soil from the surface all the way to bedrock.
C) the A horizon only.
D) the surface of the soil body.

Question 39

Which of the following soil layers would usually contain the greatest amount of clay in a well-developed soil?

A) A
B) B
C) C
D) R
E) E

Question 40

B horizons are often ________ in color because of ________.

A) dark; accumulation of humus
B) dark; it is made of dark colored, mafic minerals
C) reddish or yellowish; the minerals they contain are often chemically oxidized
D) reddish or yellowish; the minerals they contain are often chemically reduced

Question 41

Which subsurface diagnostic horizon is used as brick because it is so hard?

A) argillic
B) plinthite
C) spodic
D) salic

Question 42

Which diagnostic epidpedon is associated with the fertile soils of the central U.S., is dark in color, humus-rich, and has good structure?

A) ochric
B) histic
C) mollic
D) plaggen

Question 43

A high CEC means that

A) soil colloids can store and exchange more cations.
B) activity between colloids and the soil solution is high.
C) the soil is probably fertile.
D) All of these are correct.

Question 44

The principal natural soil-forming factors

A) are both dynamic and passive in nature.
B) include climate, parent material, topography, biotic processes and time.
C) are all inorganic.
D) include peds, separates, solums, and horizons.
E) Both A and B are related soil forming factors.

Question 45

A soil order characteristic of the Amazon Basin is a/an

A) Alfisol.
B) Aridisol.
C) Spodosol.
D) Oxisol.

Question 46

Salinization is likely to occur

A) in the tropics.
B) in areas of high potential evapotranspiration and low actual evapotranspiration.
C) in humid climate regions.
D) in areas characterized by sandy soils and coniferous forests.

Question 47

Which pedogenic regime is associated with tropical soils?

A) calcification
B) podzolization
C) salinization
D) laterization

Question 48

Which of the following is true?

A) Both the direct and indirect costs of soil erosion is estimated at hundreds of billions of dollars worldwide.
B) Soil that has eroded could take centuries to be replaced.
C) Loss of soil, combined with exponential population growth, could lead to serious food shortages.
D) Fertilizers can maintain soil fertility and productivity into the distant future-even if the soil is eroding.
E) All of the above.

Question 49

Which pedogenic regime tends to occur in cool, coniferous forests, and results in acidification of the soil?

A) laterization
B) salinization
C) podzolation
D) calcification

Question 50

Soil erosion in the United States

A) is virtually under control given all the conservation practices implemented.
B) is causing over 30 percent of farmlands in this country to erode faster than the soil can be replaced.
C) has not been adequately mapped by the Soil Conservation Service.
D) is highest in the northeastern states.

Question 51

The ability of certain soil particles to transfer mineral ions between their surfaces and the soil solution is referred to as

A) soil acidity.
B) soil alkalinity.
C) colloidal action.
D) cation-exchange capacity.

Question 52

Broadleaf trees tend to make the soil more ________, whereas conifers tend to make it more ________.

A) acidic; alkaline
B) alkaline; acidic
C) acidic; neutral
D) neutral; acidic

Question 53

At present, which of the soil orders of Soil Taxonomy occupy the most land area in the United States?

A) Oxisols
B) Aridisols
C) Mollisols
D) Spodosols

Question 54

Which of the following is false?

A) Soil erosion is occurring throughout most of the densely inhabited regions of the world.
B) Soil that has eroded could take centuries to be replaced.
C) Loss of soil, combined with exponential population growth, could lead to serious food shortages.
D) Fertilizers can maintain soil fertility and productivity into the distant future-even if the soil is eroding.
E) Both the direct and indirect costs of soil erosion is estimated at hundreds of billions of dollars worldwide.

Question 55

Important soil components that are involved in the retention of ions formed by clay and organic particles are called

A) peds.
B) separates.
C) colloids.
D) pH holders.

Question 56

Which of the following is false regarding soil erosion?

A) It takes 5 years to mature a few centimeters of soil.
B) 35% of farmland is losing soil faster than it can form.
C) Soil erosion can be controlled by planting on the contour.
D) Soil losses cost the U.S. $25 billion each year.
E) Thirty-five percent of farms worldwide are losing soil faster than it is being formed.

Question 57

Which pedogenic regime occurs in cool, wet climates in areas of poor drainage, and results in the accumulation of humus-as well as a water-saturated layer of gray clay?

A) laterization
B) salinization
C) podzolation
D) gleization

Question 58

The soil at the base of a hillslope is likely to be ________ compared to the soil on the slope.

A) thicker
B) wetter
C) nutrient-rich
D) all of these
E) none of these

Question 59

Acidic soils

A) are generally defined as soils with a pH of about 6 or less.
B) cause more rapid weathering and leaching of nutrients.
C) are generally very fertile.
D) all of the above
E) Only A and B are true.

Question 60

Which of the following lists of soil categories gives the proper hierarchy for the Soil Taxonomy system-from the largest grouping to the smallest unit (i.e., from least to most in terms of the number of soils included)?

A) orders, suborders, soil series, small groups
B) soil orders, suborders, great groups, subgroups, families, series
C) pedon, polypedon, horizons, profiles
D) epipedon, subsurface diagnostic horizon

Question 61

Irrigation of Aridisols tends to promote

A) gleization.
B) podzolation.
C) salinization.
D) laterization.

Question 62

Which type of soil is the least developed?

A) Inceptisols
B) Entisols
C) Oxisols
D) Mollisols

Question 63

Oxisols are ________ and ________.

A) highly leached; nutrient-rich
B) highly leached; nutrient-poor
C) poorly leached; nutrient-rich
D) poorly leached; nutrient-poor

Question 64

The great grassland soils of the world are called

A) Spodosols.
B) Aridisols.
C) Ultisols.
D) Mollisols.

Question 65

Ultisols experience ________ leaching and therefore have relatively ________ levels of cations.

A) substantial; high
B) substantial; low
C) limited; high
D) limited; low

Question 66

Recent, undeveloped soils are known as

A) Oxisols.
B) Ultisols.
C) Entisols.
D) Spodosols.

Question 67

At present, which of the soil orders of Soil Taxonomy occupy the most land area worldwide?

A) Oxisols
B) Aridisols
C) Alfisols
D) Ultisols

Question 68

Which soil order would tend to occur in the southeastern U.S., with its high temperatures and humid environment?

A) Ultisols
B) Spodosols
C) Aridisols
D) Mollisols

Question 69

Selenium contamination of western soils is related to

A) the application of chemicals by farmers.
B) reliance of natural precipitation with no irrigation.
C) concentration of a natural element in the soil through irrigation drainage collection.
D) none of the above

Question 70

Gelisols are most likely to be found in

A) Canada.
B) Arizona.
C) Panama.
D) Greece.

Question 71

Which pedogenic regime is associated with Spodosols?

A) calcification
B) podzolization
C) salinization
D) laterization

Question 72

The moist versions of mollisols are the

A) Oxisols.
B) Ultisols.
C) Vertisols.
D) Alfisols.

Question 73

Which of the following soils would have limited horizon development and would be destructive of buildings and roads?

A) Inceptisols
B) Vertisols
C) Mollisols
D) Alfisols

Question 74

Andisols are ________ soils that are ________ in CEC.

A) volcanic; high
B) volcanic; low
C) floodplain; high
D) floodplain; low

Question 75

In a transect across the 98th meridian, from west to east, which of the following gives the correct sequence of soil orders?

A) Alfisols, Aridisols, Ultisols
B) Aridisols, Oxisols, Mollisols
C) Aridisols, Spodosols, Ultisols
D) Aridisols, Mollisols, Alfisols
E) Alfisols, Mollisols, Aridisols

Question 76

Mollisols are associated with

A) the greatest timber harvests in the world.
B) the greatest grain harvests in the world.
C) floodplains.
D) intense leaching.

Question 77

Soils characteristic of the northern coniferous forests are the

A) Spodosols.
B) Aridisols.
C) Alfisols.
D) Mollisols.

Question 78

Prairie soil can contain evidence of processes that date back

A) no more than 50 years.
B) no more than 500 years.
C) no more than 1000 years.
D) at least 15,000 years.

Question 79

Because Aridisols form in arid environments, they are likely to

A) be very thin and poorly developed.
B) contain little organic matter.
C) contain calcic and salic horizons.
D) all of the above
E) none of the above

Question 80

Accumulations of thick organic matter, such as in the beds of former lakes or bogs, are classified as

A) Entisols.
B) Histosols.
C) Vertisols.
D) Mollisols.