Question

Lateritic soils are ....... and Podzolised soils are .......
(i) Sesquioxides leached soils and Sesquioxides enriched soils respectively
(ii) Sesquioxides leached soils and Silica enriched soils respectively
(iii) Silica enriched soils and Sesquioxides enriched soils respectively
(iv) Sesquioxides enriched soils and Silica enriched soils respectively
Choose the correct answer from the given below options:

• A. (i) and (ii) only
• B. (i) and (iii) only
• C. (i) only
• D. (iv) only

Hint:

To remember this:
- Tropical Laterites leach silica out \( \rightarrow \) Enriched in Sesquioxides (Fe and Al, giving them a red color).
- Cool temperate Podzols leach sesquioxides out \( \rightarrow \) Enriched in Silica (giving them an ash-gray, sandy appearance).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Laterization and Podzolization are two distinct soil-forming processes (pedogenic regimes) that occur under different climatic conditions and vegetation covers, resulting in contrasting soil chemical profiles.

Step 2: Detailed Explation:
Let's alyze the chemical weathering processes in both soil types:
1. Laterization (Lateritic soils): This process occurs in warm, humid tropical climates characterized by high rainfall and high temperatures.
Under these conditions, intense weathering leads to the rapid dissolution and leaching of silica (\( \text{SiO}_2 \)) down the soil profile (desilication).
Conversely, iron and aluminum oxides, collectively known as sesquioxides (\( \text{Fe}_2\text{O}_3 \) and \( \text{Al}_2\text{O}_3 \)), are highly insoluble under these conditions.
These sesquioxides accumulate in the upper horizons, making lateritic soils sesquioxides-enriched soils.
2. Podzolization (Podzolised soils): This process occurs in cool, humid temperate climates, often under acid-litter producing coniferous forests.
The acidic organic matter forms soluble complexes with iron and aluminum (sesquioxides) and leaches them out of the upper A horizon (eluviation).
Silica is highly resistant to acid leaching and remains behind, leaving the upper A horizon highly enriched in silica.
Thus, podzolised soils are silica-enriched soils in their eluvial horizons.
Therefore, statement (iv) correctly describes both soil types, which matches Option (D).

Step 3: Fil Answer
Lateritic soils are sesquioxides-enriched, and podzolised soils are silica-enriched, as stated in statement (iv).