Environmental Studies · Geography

Soil Science

1,537 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
  1. Red soil

  2. Black soil

  3. Alluvial soil

  4. Laterite soil

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Black soil (Regur) is formed from the weathering of volcanic rocks, particularly basalt from ancient lava flows. This soil is rich in iron, aluminum, and magnesium, giving it characteristic dark color and high fertility for cotton. The Deccan Plateau's extensive black soil regions originated from volcanic activity millions of years ago.

Multiple choice
  1. Regur

  2. Bhabar

  3. Bangar

  4. Khadar

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Regur (black cotton soil) is formed from the weathering of volcanic basalt rocks, primarily in the Deccan Plateau region. In contrast, Bhabar, Bangar, and Khadar are all alluvial soil types formed by river deposition in the Indo-Gangetic plains. The three alluvial soils share a similar depositional origin, while Regur has a completely different formation mechanism from volcanic parent material.

Multiple choice
  1. Brown soil

  2. Black soil

  3. Wheatish soil

  4. None of these

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Black soil (regur soil) is ideal for cotton because it has high clay content, excellent moisture retention, and becomes sticky when wet but cracks when dry. These properties allow cotton roots to penetrate deeply while maintaining adequate moisture. Cotton is traditionally the main crop in black soil regions of Deccan plateau.

Multiple choice
  1. exhaustible renewable resource

  2. exhaustible non-renewable resource

  3. inexhaustible resource

  4. inexhaustible non-renewable resource

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Soil is an inexhaustible resource.

Multiple choice
  1. red soil

  2. black soil

  3. laterite soil

  4. alluvial soil

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The northern plains of India (Indo-Gangetic plains) are formed by alluvial deposits brought by rivers like Ganga, Indus, and Brahmaputra. Alluvial soil is highly fertile and ideal for agriculture. Red soil, black soil, and laterite soil are found in other regions (peninsular India, Deccan plateau).

Multiple choice
  1. Regur

  2. Kallar

  3. Chernozemi

  4. Usar soil

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Black cotton soil is a type of black soil found in the Deccan Plateau region of India. It is known as Regur because of its high clay content and characteristic color. This soil is ideal for cotton cultivation due to its moisture-retention properties.

Multiple choice
  1. Sandy clay

  2. Alluvial clay

  3. Red clay

  4. Red and Black mixed

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alluvial soil is the predominant soil type in Uttar Pradesh, covering most of the Gangetic plains. This soil is formed by the deposition of sediments by the Ganga and its tributaries over thousands of years, making it extremely fertile for agriculture.

Multiple choice
  1. Black

  2. Alluvial

  3. Sandy

  4. Red

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Red soils are typically less fertile, acidic, and deficient in nitrogen, phosphorus, and organic matter, making them difficult to cultivate without substantial fertilization. Black soil (regur) is actually very fertile, ideal for cotton. Alluvial soil is the most fertile, deposited by rivers. Sandy soil has low water retention but is not as hard to cultivate as red soil.

Multiple choice
  1. Climate

  2. Soil gravity

  3. Magnitude of the soil dimension

  4. Rock cover

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Climate (temperature, rainfall, and seasonal variations) is the most important factor in soil formation as it influences weathering rates, organic matter decomposition, and chemical processes. Different climates produce different soil types (e.g., laterite in tropical areas, chernozem in grasslands). Soil gravity, rock cover, and soil dimension are not primary factors in pedogenesis (soil formation).

Multiple choice
  1. ascorbic acid

  2. iron

  3. ferrite

  4. potash

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Red soil gets its characteristic color from iron oxide (Fe2O3) content, which forms through extensive leaching in tropical and subtropical regions. The iron accumulates in the soil profile, creating the reddish hue. Ascorbic acid is vitamin C, not a soil component. Ferrite is a magnetic iron compound but not the coloring agent. Potash is potassium, unrelated to soil color.

Multiple choice
  1. Snake

  2. Lichen

  3. Lion

  4. Deer

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lichens are pioneer organisms that secrete acids to break down rocks into soil particles, initiating soil formation in barren landscapes. Animals like snakes, lions, and deer live in developed ecosystems but do not contribute to creating soil from parent rock material.