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

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

  1. C-fern

  2. Tree fern

  3. Brake fern

  4. Vegetable fern

  5. Licorice 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

_________ and __________ is required for growing cotton?

  1. Clayey<font size="2">, </font>oamy soil

  2. Well aerated, loamy soil

  3. Fertile<font size="2">, </font> clayey soil

  4. Organic, inorganic matter
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cotton requires well-aerated, loamy soil that allows good drainage and prevents waterlogging. Loamy soil provides the right balance of sand, silt, and clay. Cotton cannot grow in waterlogged clayey soil and needs proper aeration for root development.

Multiple choice

What are biofertilisers?

  1. Manure

  2. Organisms used to improve fertility of soil

  3. Organic chemicals

  4. Organisms which naturally increases fertility of soil
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Biofertilisers are organisms which increase the nutrient availability in crop plants directly or through soil enrichment.

Multiple choice

Why is phosphorous (P) is not effective in strongly acidic or basic soils?

  1. P reacts with acidic or basic soils to form toxic compounds.

  2. P is insoluble in strongly acidic or basic soils.

  3. High alkalinity or acidity leads to poor absorption.

  4. P gets converted into gas on coming in contact with acidic or basic soil.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

P is insoluble in strongly acidic or basic soils. Phosphorus can react strongly with Fe and Al components of acid tropical soils, thereby becoming unavailable for plant uptake

Multiple choice

Urea is a

  1. sodium fertiliser

  2. phosphatic fertiliser

  3. nitrogenous fertiliser

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

Urea (CO(NH2)2) is a nitrogenous fertilizer containing approximately 46% nitrogen by weight, making it one of the highest nitrogen content fertilizers available. It provides nitrogen in an organic form that plants can convert to usable nitrates. Sodium, phosphatic, and potassium fertilizers provide different nutrients.

Multiple choice

The process of decomposition inside the Earth takes place _____.

  1. in the presence of O2 (oxygen)

  2. in the absence of O2

  3. in the presence of O3 (ozone)

  4. in the absence of CO2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Decomposition takes place deep under the surface of the earth due to the activity of anaerobic bacteria/microorganisms. Absence of oxygen is a pre-requisite for this.

Multiple choice

Decomposition of organic matter is brought about by

  1. protozoa

  2. plants

  3. micro-organisms

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Decomposition of organic matter (dead plants, animals, waste) is primarily carried out by microorganisms including bacteria and fungi. These saprotrophs break down complex organic molecules, recycling nutrients back into the ecosystem. Protozoa contribute to but don't drive decomposition.

Multiple choice

Directions: For this question, select the best of the answer choices given.

Two experimental garden plots were each planted with the same number of tomato plants. Magnesium salts were added to the first plot but not to the second. The first plot produced 20 pounds of tomatoes and the second plot produced 10 pounds. Since nothing else but water was added to either plot, the higher yields in the first plot must been due to the magnesium salts. Which of the following, if true, most seriously weakens the argument above?

  1. A small amount of the magnesium salts from the first plot leached into the second plot.

  2. Tomato plants in a third experimental plot, to which a high-nitrogen fertilizer was added, but no magnesium salts, produced 15 pounds of tomatoes.

  3. Four different types of tomatoes were grown in equal proportions in each of the plots.

  4. Some weeds that compete with tomatoes cannot tolerate high amounts of magnesium salts in the soil.

  5. The two experimental plots differed from each other with respect to soil texture and exposure to sunlight.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The argument incorrectly assumes magnesium salts caused higher tomato yields while ignoring other potential variables. Option E seriously weakens this by showing the plots differed in soil texture and sunlight exposure - factors that significantly affect plant growth. If the plots weren't comparable except for magnesium, the conclusion is invalid. Options A, B, C, and D don't address the core comparability issue: leaching would affect both plots (A), nitrogen fertilizer results don't weaken the magnesium conclusion (B), tomato types being the same supports rather than weakens (C), and weed intolerance doesn't challenge the magnesium effect (D).

Multiple choice

Potassium is taken by plants from the soil in the form of:

  1. potassium chlorate

  2. potassium hydroxide

  3. potassium nitrate

  4. can be in any form
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Plants absorb potassium from soil primarily in the form of potassium ions (K+), commonly found in potassium nitrate (KNO3), potassium phosphate, or other soluble potassium salts. Potassium nitrate is a common fertilizer source. Potassium chlorate is toxic to plants, and potassium hydroxide is too alkaline.

Multiple choice

Characteristic smell of onion bulb is due to the presence of:

  1. lipid content

  2. reserve carbohydrates

  3. sulphur compounds

  4. bad odour of soil in which they are cultivated.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Onions contain organosulfur compounds like allyl propyl disulfide that produce their characteristic pungent smell when cells are damaged. These sulfur-containing compounds are secondary metabolites that give Allium vegetables their distinctive aroma and flavor.