0

Soil Microbiology and Ecology

Description: This quiz covers the fundamental concepts of soil microbiology and ecology, including the role of microorganisms in nutrient cycling, soil structure, and plant growth.
Number of Questions: 15
Created by:
Tags: soil microbiology ecology nutrient cycling soil structure plant growth
Attempted 0/15 Correct 0 Score 0

What is the primary role of microorganisms in soil?

  1. Decomposing organic matter

  2. Producing oxygen

  3. Fixing nitrogen

  4. All of the above


Correct Option: D
Explanation:

Microorganisms play a vital role in soil by decomposing organic matter, producing oxygen, and fixing nitrogen, which are essential for plant growth and soil fertility.

Which of the following is NOT a beneficial effect of microorganisms in soil?

  1. Nutrient cycling

  2. Soil structure improvement

  3. Plant disease suppression

  4. Greenhouse gas production


Correct Option: D
Explanation:

While microorganisms play a crucial role in nutrient cycling, soil structure improvement, and plant disease suppression, greenhouse gas production is a negative impact associated with certain microbial activities.

What is the process by which microorganisms break down organic matter in soil?

  1. Nitrification

  2. Denitrification

  3. Decomposition

  4. Mineralization


Correct Option: C
Explanation:

Decomposition is the process by which microorganisms break down organic matter into simpler compounds, releasing nutrients back into the soil.

Which group of microorganisms is primarily responsible for nitrogen fixation in soil?

  1. Bacteria

  2. Fungi

  3. Protozoa

  4. Algae


Correct Option: A
Explanation:

Nitrogen-fixing bacteria, such as Rhizobium and Azotobacter, are responsible for converting atmospheric nitrogen into a form that can be utilized by plants.

What is the term for the process by which microorganisms convert organic nitrogen into inorganic forms?

  1. Nitrification

  2. Denitrification

  3. Ammonification

  4. Mineralization


Correct Option: C
Explanation:

Ammonification is the process by which microorganisms convert organic nitrogen into ammonia, which is then further converted into nitrate and nitrite through nitrification.

Which soil horizon is typically the most fertile and contains the highest concentration of organic matter?

  1. O horizon

  2. A horizon

  3. B horizon

  4. C horizon


Correct Option: B
Explanation:

The A horizon, also known as the topsoil, is the most fertile layer of soil and contains the highest concentration of organic matter, nutrients, and microbial activity.

What is the term for the process by which microorganisms convert nitrate into nitrogen gas?

  1. Nitrification

  2. Denitrification

  3. Ammonification

  4. Mineralization


Correct Option: B
Explanation:

Denitrification is the process by which microorganisms convert nitrate into nitrogen gas, which is released into the atmosphere.

Which of the following is NOT a factor that influences microbial activity in soil?

  1. Temperature

  2. Moisture

  3. pH

  4. Gravity


Correct Option: D
Explanation:

Temperature, moisture, and pH are key factors that influence microbial activity in soil, while gravity does not directly affect microbial processes.

What is the term for the symbiotic relationship between certain fungi and plant roots?

  1. Mycorrhizae

  2. Rhizobia

  3. Actinomycetes

  4. Cyanobacteria


Correct Option: A
Explanation:

Mycorrhizae are symbiotic associations between certain fungi and plant roots, where the fungus helps the plant absorb nutrients from the soil in exchange for carbohydrates.

Which group of microorganisms is primarily responsible for the decomposition of cellulose in soil?

  1. Bacteria

  2. Fungi

  3. Protozoa

  4. Algae


Correct Option: B
Explanation:

Fungi, particularly white-rot fungi, are the primary decomposers of cellulose, a major component of plant cell walls, in soil.

What is the term for the process by which microorganisms convert organic phosphorus into inorganic forms?

  1. Phosphorization

  2. Dephosphorization

  3. Mineralization

  4. Immobilization


Correct Option: C
Explanation:

Mineralization is the process by which microorganisms convert organic phosphorus into inorganic forms, making it available for plant uptake.

Which soil horizon is typically the most compacted and contains the highest concentration of clay and minerals?

  1. O horizon

  2. A horizon

  3. B horizon

  4. C horizon


Correct Option: C
Explanation:

The B horizon, also known as the subsoil, is typically the most compacted layer of soil and contains the highest concentration of clay and minerals.

What is the term for the process by which microorganisms convert organic sulfur into inorganic forms?

  1. Sulfurization

  2. Desulfurization

  3. Mineralization

  4. Immobilization


Correct Option: C
Explanation:

Mineralization is the process by which microorganisms convert organic sulfur into inorganic forms, making it available for plant uptake.

Which group of microorganisms is primarily responsible for the decomposition of lignin in soil?

  1. Bacteria

  2. Fungi

  3. Protozoa

  4. Algae


Correct Option: B
Explanation:

Fungi, particularly brown-rot fungi, are the primary decomposers of lignin, a complex organic compound found in plant cell walls.

What is the term for the process by which microorganisms convert organic potassium into inorganic forms?

  1. Potassiumization

  2. Depotassification

  3. Mineralization

  4. Immobilization


Correct Option: C
Explanation:

Mineralization is the process by which microorganisms convert organic potassium into inorganic forms, making it available for plant uptake.

- Hide questions