Question 1

All but a few nematodes are pests, attacking either economic or wild plants.

Accepted Answer

A) True 
 B)False  False

Question 2

Soil microorganisms often compete with higher plants for mineral nutrients, such as nitrogen.

Accepted Answer

A) True 
 B)False  True

Question 3

Termites tend to enrich soils in the tropics much the same way as earthworms do in temperate region soils.

Accepted Answer

A) True 
 B)False  False

Question 4

In nature, beneficial mycorrhizae form with the roots of _____.

Accepted Answer

A)  coniferous trees 
B)  grasses 
C)  legumes 
D)  broad leaf trees 
E)  all of the above 
A)  coniferous trees 
B)  grasses 
C)  legumes 
D)  broad leaf trees 
E)  all of the above

Question 5

Oxidation or reduction of inorganic soil constituents such as iron and sulfur is carried out by members of which group(s) of microorganisms.

Accepted Answer

A)  actinomycetes 
B)  bacteria 
C)  fungi 
D)  A and C 
E)  all of the above 
A)  actinomycetes 
B)  bacteria 
C)  fungi 
D)  A and C 
E)  all of the above

Question 6

Research has shown that most herbicides and insecticides used in agriculture drastically reduce the numbers of living meso- and microorganisms in soils for several years after the application of these chemicals.

Accepted Answer

A) True 
 B)False

Question 7

Plant roots are an important source of carbon for many soil organisms which are beneficial to plants.

Accepted Answer

A) True 
 B)False

Question 8

Members of this (these) microbial group(s) are responsible for a major proportion of the nitrogen fixed globally in symbiosis with higher plants.

Accepted Answer

A)  actinomycetes 
B)  bacteria 
C)  fungi 
D)  A and B 
E)  all of the above 
A)  actinomycetes 
B)  bacteria 
C)  fungi 
D)  A and B 
E)  all of the above

Question 9

Certain soil fungi and actinomycetes are known to produce specialized organic compounds that inhibit or kill other, competing microorganisms in the soil, but so far scientists have not been able to put any of these compounds to practical use.

Accepted Answer

A) True 
 B)False

Question 10

Mycorrhizae do not normally kill their host plants, but merely reduce the efficiency of the plant root system.

Accepted Answer

A) True 
 B)False

Question 11

Algae are single-celled plants that function principally as primary producers in the soil ecosystem.

Accepted Answer

A) True 
 B)False

Question 12

Compared to the bulk soil in which the earthworms live, earthworm casts contain ____.

Accepted Answer

A)  less of most plant-available nutrients 
B)  more nitrogen but less of other plant-available nutrients 
C)  more of most plant-available nutrients 
D)  more sand and silt 
E)  less organic matter 
A)  less of most plant-available nutrients 
B)  more nitrogen but less of other plant-available nutrients 
C)  more of most plant-available nutrients 
D)  more sand and silt 
E)  less organic matter

Question 13

Actinomycetes tend to dominate soils that are either very acid, very cold, or very dry.

Accepted Answer

A) True 
 B)False

Question 14

In most soils the overall population (numbers) of microorganisms changes with time, generally following changes in the _____.

Accepted Answer

A)  supply of decomposable organic matter 
B)  supply of oxygen 
C)  porespace 
D)  availability of root infection sites 
E)  concentrations of antibiotics 
A)  supply of decomposable organic matter 
B)  supply of oxygen 
C)  porespace 
D)  availability of root infection sites 
E)  concentrations of antibiotics

Question 15

Soil detritivores feed principally on ___.

Accepted Answer

A)  smaller organisms 
B)  plant roots 
C)  larger, but defenseless animals 
D)  dead tissues 
E)  microorganisms 
A)  smaller organisms 
B)  plant roots 
C)  larger, but defenseless animals 
D)  dead tissues 
E)  microorganisms

Question 16

Meso- and macrofauna contribute to organic matter decomposition primarily by ______.

Accepted Answer

A)  enzymatic digestion of plant residues 
B)  enhancement of microbial activity 
C)  predation 
D)  synthesis of humus 
E)  none of the above 
A)  enzymatic digestion of plant residues 
B)  enhancement of microbial activity 
C)  predation 
D)  synthesis of humus 
E)  none of the above

Question 17

Disease suppressive soil often results from _____.

Accepted Answer

A)  Fumigation with a volatile chemical. 
B)  Heating the soil by natural solarization or steam heat. 
C)  Repeated tillage to keep the soil bare for at least one full year. 
D)  Adding organic materials to the soil that stimulate diverse microorganisms. 
E)  All of the above. 
A)  Fumigation with a volatile chemical. 
B)  Heating the soil by natural solarization or steam heat. 
C)  Repeated tillage to keep the soil bare for at least one full year. 
D)  Adding organic materials to the soil that stimulate diverse microorganisms. 
E)  All of the above.

Question 18

Which of the following organisms can commonly be seen with the unaided eye in organic matter-rich soils?

Accepted Answer

A)  fungi 
B)  bacteria 
C)  nematodes 
D)  actinomycetes 
E)  none of the above 
A)  fungi 
B)  bacteria 
C)  nematodes 
D)  actinomycetes 
E)  none of the above

Question 19

Which of the following groups is not considered to include important primary consumers in the soil ecosystem?

Accepted Answer

A)  detritivores 
B)  herbivores 
C)  fungi 
D)  saprophytes 
E)  predators 
A)  detritivores 
B)  herbivores 
C)  fungi 
D)  saprophytes 
E)  predators

Question 20

Most anaerobic organisms in soils are bacteria.

Accepted Answer

A) True 
 B)False

All but a few nematodes are pests, attacking either economic or wild plants.

Soil microorganisms often compete with higher plants for mineral nutrients, such as nitrogen.

Termites tend to enrich soils in the tropics much the same way as earthworms do in temperate region soils.

In nature, beneficial mycorrhizae form with the roots of _____.

Oxidation or reduction of inorganic soil constituents such as iron and sulfur is carried out by members of which group(s) of microorganisms.

Research has shown that most herbicides and insecticides used in agriculture drastically reduce the numbers of living meso- and microorganisms in soils for several years after the application of these chemicals.

Plant roots are an important source of carbon for many soil organisms which are beneficial to plants.

Members of this (these) microbial group(s) are responsible for a major proportion of the nitrogen fixed globally in symbiosis with higher plants.

Certain soil fungi and actinomycetes are known to produce specialized organic compounds that inhibit or kill other, competing microorganisms in the soil, but so far scientists have not been able to put any of these compounds to practical use.

Mycorrhizae do not normally kill their host plants, but merely reduce the efficiency of the plant root system.

Algae are single-celled plants that function principally as primary producers in the soil ecosystem.

Compared to the bulk soil in which the earthworms live, earthworm casts contain ____.

Actinomycetes tend to dominate soils that are either very acid, very cold, or very dry.

In most soils the overall population (numbers) of microorganisms changes with time, generally following changes in the _____.

Soil detritivores feed principally on ___.

Meso- and macrofauna contribute to organic matter decomposition primarily by ______.

Disease suppressive soil often results from _____.

Which of the following organisms can commonly be seen with the unaided eye in organic matter-rich soils?

Which of the following groups is not considered to include important primary consumers in the soil ecosystem?

Most anaerobic organisms in soils are bacteria.

The Soils Around Us

Formation of Soils From Parent Materials

Soil Classification

Soil Architecture and Physical Properties

Soil Water: Characteristics and Behavior

Soil and the Hydrologic Cycle

Soil Aeration and Temperature

The Colloidal Fraction: Seat of Soil Chemical and Physical Activity

Soil Acidity, Alkalinity, Aridity and Salinity

Soil Organic Matter Overview

Nutrient Cycles and Soil Fertility

Practical Nutrient Management

Soil Erosion and Its Control

Soils and Chemical Pollution

Filters

Exam 10: Organisms and Ecology of the Soil

All but a few nematodes are pests, attacking either economic or wild plants.

Soil microorganisms often compete with higher plants for mineral nutrients, such as nitrogen.

Termites tend to enrich soils in the tropics much the same way as earthworms do in temperate region soils.

In nature, beneficial mycorrhizae form with the roots of _____.

Oxidation or reduction of inorganic soil constituents such as iron and sulfur is carried out by members of which group(s) of microorganisms.

Research has shown that most herbicides and insecticides used in agriculture drastically reduce the numbers of living meso- and microorganisms in soils for several years after the application of these chemicals.

Plant roots are an important source of carbon for many soil organisms which are beneficial to plants.

Members of this (these) microbial group(s) are responsible for a major proportion of the nitrogen fixed globally in symbiosis with higher plants.

Certain soil fungi and actinomycetes are known to produce specialized organic compounds that inhibit or kill other, competing microorganisms in the soil, but so far scientists have not been able to put any of these compounds to practical use.

Mycorrhizae do not normally kill their host plants, but merely reduce the efficiency of the plant root system.

Algae are single-celled plants that function principally as primary producers in the soil ecosystem.

Compared to the bulk soil in which the earthworms live, earthworm casts contain ____.

Actinomycetes tend to dominate soils that are either very acid, very cold, or very dry.

In most soils the overall population (numbers) of microorganisms changes with time, generally following changes in the _____.

Soil detritivores feed principally on ___.

Meso- and macrofauna contribute to organic matter decomposition primarily by ______.

Disease suppressive soil often results from _____.

Which of the following organisms can commonly be seen with the unaided eye in organic matter-rich soils?

Which of the following groups is not considered to include important primary consumers in the soil ecosystem?

Most anaerobic organisms in soils are bacteria.

The Soils Around Us

Formation of Soils From Parent Materials

Soil Classification

Soil Architecture and Physical Properties

Soil Water: Characteristics and Behavior

Soil and the Hydrologic Cycle

Soil Aeration and Temperature

The Colloidal Fraction: Seat of Soil Chemical and Physical Activity

Soil Acidity, Alkalinity, Aridity and Salinity

Soil Organic Matter Overview

Nutrient Cycles and Soil Fertility

Practical Nutrient Management

Soil Erosion and Its Control

Soils and Chemical Pollution

Filters