Environmental Studies · Biology

Soil Science and Fertilizers

1,509 Questions

Soil science focuses on soil formation, classification, and fertility management using fertilizers and organic amendments. Agricultural and environmental science exams heavily feature questions on biofertilizers, mycorrhiza, and phytoremediation. Practice these questions to build a strong understanding of soil nutrient cycles.

Phytoremediation techniquesOrganic soil amendmentsBiofertilizers and mycorrhizaNitrous oxide emissionsIn-situ soil remediationGreen manuring effects

Soil Science and Fertilizers Questions

Multiple choice

Which of the following functions is not performed by roots?

  1. Taking minerals from soil.

  2. Helping in the prevention of erosion.

  3. Making food for plant.

  4. Giving strength to the plant.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Roots perform several essential functions: they absorb water and minerals from soil (option A), anchor the plant and provide strength (option D), and help prevent soil erosion (option B). However, roots do NOT make food - that function is performed by leaves through photosynthesis. Therefore, making food for the plant is the correct answer as it is NOT a root function.

Multiple choice

Legume plants are important for atmosphere because they

  1. help in NO2 fixation

  2. do not help in NO2 fixation

  3. increase soil fertility

  4. Both (1) and (2)

  5. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Legume plants are important for atmosphere because they help to increase the fertility of soil by fixing nitrogen in the soil. 

Multiple choice

Bioremediation is the use of microbes to clean up contaminated soil and groundwater. Which among the following fern is used as a potential bioremediation plant for absorbing arsenic from the soil?

  1. Vegetable fern

  2. Licorice fern

  3. Brake fern

  4. Tree ferns

  5. C-fern
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Brake fern was discovered to have the ability to "hyperaccumulate" (absorb large amounts of) arsenic from soil. The fern was growing at a central Florida site contaminated with large amounts of copper arsenate in the soil. The discovery may lead to the use of this fern as a potential bioremediation plant.

Multiple choice

Which of the following statements is/are correct?

a. In the gaseous cycle, the main reservoir of nutrients is the atmosphere and the ocean. b. In the sedimentary cycle, the main reservoir is the soil and the sedimentary and other rocks of Earth’s crust. c. These biogeochemical cycles are largely energised by solar insolation.

  1. a only

  2. b only

  3. c only

  4. a and b

  5. a, b and c
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct answer as all the given statements are correct.

Multiple choice

Select the biofertilizer in the following

  1. Compost

  2. Ammonium sulphate

  3. Cattle dung

  4. Algae and blue-green algae
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Algae and blue-green algae (cyanobacteria) are biofertilizers as they fix atmospheric nitrogen and enrich soil fertility. Compost and cattle dung are organic manures, not biofertilizers. Ammonium sulphate is a chemical fertilizer. Biofertilizers are living microorganisms that enhance nutrient availability.

Multiple choice

Maximum biological activities occur in ________ of the soil.

  1. horizon A

  2. horizon B

  3. horizon O

  4. horizon C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Horizon A (topsoil) contains the highest organic matter, humus, and root density, supporting maximum biological activity including decomposition, nutrient cycling, and soil organism activity. This is where most plant roots and soil organisms are concentrated.

Multiple choice

Legitimately, an average garden soil consists of

  1. 70% minerals, 10% water and 10% organic matter

  2. 50% minerals, 40% organic matter, 10% water and 20% H2O

  3. 40% minerals, 25% water, 10% organic matter and 25% air

  4. Any of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ideal garden soil composition includes approximately 45% minerals, 25% water, 25% air, and 5% organic matter. Option C with 40% minerals, 25% water, 25% air, and 10% organic matter is closest to this standard. Options A and B have incorrect percentages, and option D is vague.

Multiple choice

A balance fertilizer for plants is

  1. urea

  2. super phosphate of time

  3. ammonium sulphate

  4. compost
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Compost is considered a balanced fertilizer because it contains a mix of essential nutrients (nitrogen, phosphorus, potassium) and organic matter that improves soil structure. Urea, super phosphate, and ammonium sulfate are single-nutrient fertilizers, lacking the complete balance plants need.

Multiple choice

Which of the following statement is/are false? a. Dark coloured soils are rich in organic matter than the light coloured soils. b. The difference in soil colour does not depends on the geographical location of the soil. c. Microorganisms cause the decomposition of dead plants and animals and release the minerals back to the soil.

  1. Only a

  2. a and b

  3. Only b

  4. a and c

  5. Only c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The difference in soil colour does not depend on the geographical location of the soil, is a false statement. Hence, it is the correct option.

Multiple choice

Which one of the following stands for the symbol pH?

  1. Phosphorus and hydrogen content in soil

  2. Percentage of Hydrogen in soil

  3. Proportion of potash and hydrogen in soil

  4. Concentration of hydrogen ions in the soil
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The symbol pH stands for 'potential of Hydrogen'. It is a logarithmic scale used to specify the acidity or basicity of an aqueous solution, based on the concentration of hydrogen ions (H+).

Multiple choice

Cattle-bone powder is used as fertilizer as it is rich in

  1. sodium

  2. phosphorus

  3. nitrogen

  4. potassium
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cattle-bone powder, often called bone meal, is a slow-release organic fertilizer. It is highly valued for its high phosphorus content, which is essential for root development and flowering in plants.

Multiple choice

Which of these is not a nutrient for plants?

  1. Water

  2. Mineral ions

  3. Carbon dioxide

  4. Nitrogen gas
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Although nitrogen is an essential nutrient, most plants cannot utilize nitrogen gas (N2) directly from the air. They must absorb nitrogen from the soil in the form of nitrates or ammonium ions.