Question

Match List-I with List-II

List-I (Nature of reaction) & List-II (Nature of the process)
(A) Reduction of iron in waterlogged soil & (I) Argilliation
(B) Leaching of dispersed particles & (II) Podsolisation
(C) Intermixing of soil horizon & (III) Gleisation
(D) Eluviation of oxides of Fe, Al & Humus & (IV) Pedoturbation

• (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
• (A) - (I), (B) - (IV), (C) - (III), (D) - (II)
• (A) - (I), (B) - (II), (C) - (IV), (D) - (III)
• (A) - (III), (B) - (I), (C) - (IV), (D) - (II)

Hint:

To remember soil processes: 'Glei-' means blue-gray clay (gleisation/waterlogging), 'Argi-' refers to clay (argilliation), and 'Turb-' means disturbance or mixing (pedoturbation).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Pedogenesis (soil formation) involves both fundamental and specific chemical, physical, and biological processes that differentiate soil horizons over time.

Step 3: Detailed Explanation:
Let us analyze and match each reaction from List-I with its corresponding process in List-II:
- (A) Reduction of iron in waterlogged soil: Under anaerobic conditions caused by waterlogging, anaerobic bacteria use ferric iron ($\text{Fe}^{3+}$) as an electron acceptor, reducing it to soluble ferrous iron ($\text{Fe}^{2+}$).
This process produces a characteristic bluish-gray soil matrix and is known as Gleisation. Therefore, (A) matches with (III).
- (B) Leaching of dispersed particles: The physical downward movement and accumulation of dispersed silicate clay particles from upper horizons (E or A) to lower horizons (B) is called clay illuviation or Argilliation. Therefore, (B) matches with (I).
- (C) Intermixing of soil horizon: The biological, physical, or mechanical mixing of soil horizons (by burrowing animals, plant roots, or frost action) is known as Pedoturbation. Therefore, (C) matches with (IV).
- (D) Eluviation of oxides of Fe, Al & Humus: Under highly acidic, cool, and humid conditions, organic acids chelate and leach iron and aluminum oxides down the soil profile, leaving a bleached, sandy silica-rich E horizon. This process is known as Podsolisation. Therefore, (D) matches with (II).
This gives the match combination: (A) - (III), (B) - (I), (C) - (IV), (D) - (II).

Step 4: Final Answer:
The correct matching sequence corresponds to option (D).