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

At field capacity, the soil contains

  1. capillary and gravitational water

  2. capillary and runaway water

  3. capillary and hygroscopic water

  4. capillary and hygroscopic water
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

At field capacity, the soil contains capillary and hygroscopic water. Field capacity is the amount of soil moisture or water content held in the soil after excess water has drained away and the rate of downward movement has decreased. 

Multiple choice

Directions: For the Assertion (A) and Reason (R) given below, choose the correct alternative. Assertion (A): Black soil is formed from the weathering of igneous rocks. Reason (R): Wheat is the main crop grown in black soil region.

  1. A is true, R is false

  2. A is false, R is true

  3. Both A and R are true, but R is not the correct explanation of A.

  4. Both A and R are true and R is the correct explanation of A.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The black soil region is a rocky region. So, R is false.

Multiple choice

Consider the following statements about the soils of India:

  1. High temperature during most of the year retards formation of humus.
  2. Soils which have humus require regular application of chemical fertilizers to remove nitrogen deficiency.
  3. Titanium salts in basalt impart black colour to the soils of the Indian plateau.
  4. Red soils are confined to the peripheral areas of the Indian plateau. Which of the statements given above are correct?

  1. 1 and 2

  2. 1, 3 and 4

  3. 2 and 3

  4. 2 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

 The decayed leaf material adds much needed humus to soil thereby increasing its fertility. Humus itself decomposes in process known as minerolisation which releases nitrogenous compounds into the soil. So, the soils which have humus should not face nitrogen deficiency.

Multiple choice

Black Cotton Soil is formed from the weathering of which of the following rocks?

  1. Igneous

  2. Metamorphic

  3. Crystalline

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

Black soil is formed by the weathering of igneous rocks and the cooling of lava after a volcanic eruption. They are mainly found in the Deccan Trap/Deccan Plateau, which includes Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh, and parts of Tamil Nadu. These soils have been formed due to the weathering of the lava rocks. This soil is also known as regur soil and black cotton soil. These soils are rich in lime, iron, magnesia and alumina, but lack in the phosphorus, nitrogen and organic matter. 

Multiple choice

Consider the following statements :

  1. The granite and gneisses give rise to red soil through weathering.

  2. The laterite soil contains the hydrated oxides of iron and aluminium.

  3. Both the red and laterite soils are poor in nitrogen, but rich in potash and phosphorus.

Which of the statements given above is/are correct?

  1. 1 and 2 only

  2. 2 only

  3. 1 and 3 only

  4. 1,2 and 3

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

Red soils are derived from crystalline rocks like granite and gneiss. Laterite soils are indeed rich in hydrated oxides of iron and aluminium. Both soil types are typically deficient in nitrogen, phosphorus, and humus, making statement 3 incorrect.

Multiple choice

Consider the following statements :

  1. Chernogem soils originate under tall grass prairie vegetation.
  2. Laterites form under hot and humid climatic conditions. Which of the statements given above is/are correct?

  1. 1 only

  2. 2 only

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chernozem (black earth) soils are indeed associated with temperate grasslands (prairies). Laterite soils form in hot, humid tropical regions where intense leaching occurs.

Multiple choice

Consider the following statements :

  1. The light sandy red and yellow soils in Balaghat, Durg and Raipur districts are of alluvial origin.

  2. In Tamil Nadu, the red soils occupy over two-thirds of its total area.

  3. The red soils of Burdwan, Birbhum and Bankura are derived and transported from Chotanagpur plateau.

Which of the statements given above is/are correct ?

  1. 1 and 2 only

  2. 2 only

  3. 1 and 3 only

  4. 1,2 and 3

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

Statement 2 is correct as red soils cover a significant portion of Tamil Nadu. Statements 1 and 3 are incorrect regarding the origin and transport of those specific red soils.

Multiple choice

Chemical weathering is most predominant in

  1. semi-arid region

  2. humid tropical region

  3. Mediterranean region

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

Chemical weathering is much more common in locations where there is a lot of water. This is because water is important to many of the chemical reactions that can take place.