Question

Laterisation involves the following

• A. Removal of $\text{Fe}$ and $\text{Al}$ complexed with humus from upper to lower horizon
• B. Removal of silica from soil
• C. Removal of silica and accumulation of sesquioxides in soil
• D. Accumulation of sesquioxides in soil

Hint:

Remember the key distinction:
- Laterization $\rightarrow$ Desilication (silica leached, sesquioxides remain).
- Podzolization $\rightarrow$ Translocation of sesquioxides and humus, leaving silica in the upper horizon.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Laterization is a soil-forming process (pedogenesis) that occurs in warm, humid tropical and subtropical regions characterized by rapid weathering and high leaching rates.

Step 2: Detailed Explanation:
- Under conditions of high rainfall and warm temperatures, primary silicate minerals weather rapidly.
- High leaching rates dissolve and remove basic cations and silica ($\text{SiO}_2$) from the soil profile (a process called desilication).
- In contrast, iron ($\text{Fe}$) and aluminum ($\text{Al}$) oxides (collectively termed sesquioxides) are highly insoluble under these conditions. They remain in the upper horizons, forming a highly weathered, reddish, and structurally stable soil residue.
- Thus, laterization is defined by both the leaching of silica and the relative accumulation of iron and aluminum sesquioxides.

Step 3: Final Answer:
Laterisation involves the removal of silica and accumulation of sesquioxides in soil.