Environmental Studies · Geography

Soil Science

1,499 Questions

Soil Science examines the formation, classification, and properties of soil as a critical natural resource. This hub offers practice questions covering soil horizons, soil types like laterite and black soil, and regional soil characteristics. The content is highly useful for agriculture exams and civil services preparation.

Soil typesSoil horizonsSoil formation factorsAgricultural soil requirementsIndian soilsForest and mountain soils

Soil Science Questions

Multiple choice

Which of the following statement is INCORRECT?

  1. Black soil retains moisture and becomes exceedingly sticky.

  2. Khadar alluvium is fine textured and more fertile.

  3. Khadar alluvium is inferior to Bhangar alluvium.

  4. Black soil is rich in humus.

  5. Alluvial soil is yellow in colour.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Khadar alluvium is superior, not inferior to Bhangar alluvium. Hence, this statement is wrong.

Multiple choice

Which of the following pair is incorrect?

  1. Red soil - Regur soil

  2. Alluvial soil - Riverine soil

  3. Khadar soil - Newer alluvium

  4. Black soil - Black cotton soil

  5. Bhangar soil - older alluvium
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Black soil - Regur soil. This is the correct choice. Black soil is also known as Regur soil.

Multiple choice

By which process are the Laterite soils formed?

  1. Transportation

  2. Denudation of lava-flow

  3. Leaching

  4. Weathering of crystalline and metamorphic rocks.

  5. Humus deposition
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Laterite soil is formed by the process of leaching.

Multiple choice

Which of the following is NOT a correct statement?

  1. Laterite soil is found suitable to grow coffee in Karnataka.

  2. Khadar soil contains pebbles and gravels.

  3. Laterite soil is acidic in nature.

  4. Red soil is formed in situ.

  5. Alluvial soil is rich in Iron
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bhangar, not Khadar soil contains pebbles and gravels. Hence, this statement is wrong.

Multiple choice

Plants which tolerate soil with salt are termed as

  1. xerophyte

  2. halophytes

  3. tropophytes

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

Halophytes are plants that have adapted to grow in saline or salty soil conditions. Xerophytes are adapted to dry conditions, tropophytes adapt to seasonal changes, and saprophytes feed on dead organic matter. Halophytes have specialized mechanisms to tolerate high salt concentrations.

Multiple choice

Which type of soil is rich in humus?

  1. Sandy soil

  2. Clayey soil

  3. Loamy soil

  4. Both sandy and clayey soil
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Loamy soil is a balanced mixture of sand, silt and clay particles, making it ideal for plant growth. It contains high organic matter content in the form of humus, which improves soil structure, water retention and nutrient availability. Sandy soil drains too quickly and has low organic content, while clayey soil is too dense and poorly aerated.

Multiple choice

Which of the following types of soil is gritty and pale brown in colour?

  1. Sandy soil

  2. Clayey soil

  3. Loamy soil

  4. Black soil
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sandy soil consists of large particles that feel gritty when rubbed between fingers. Due to low organic content and large particle size, it appears pale brown, yellowish or light gray in color. Clayey soil feels smooth and is darker in color, while loamy soil is darker due to higher organic matter content.

Multiple choice

Which horizon of soil is called bed rock?

  1. O - horizon

  2. A - horizon

  3. B - horizon

  4. R - horizon
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Soil is divided into horizontal layers called horizons, including O, A, B and C horizons above the bedrock. The R-horizon represents the underlying bedrock from which soil is formed through weathering processes. It consists of unweathered parent rock material and lies below all soil horizons.

Multiple choice

What should be the nature of soil?

  1. Acidic

  2. Basic

  3. Neutral

  4. Depends on the nature of vegetation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Neutral soil (pH around 7) is generally considered ideal for most plants as it allows optimal nutrient availability. Most crops grow best in neutral conditions where essential nutrients are readily soluble and accessible to roots. Highly acidic or alkaline soils can lock up nutrients, making them unavailable to plants regardless of vegetation type.