In wet equatorial climates, the removal of silica from the soil is termed:

The correct option is Desilication.

Explanation

In wet equatorial climates, the combination of high temperatures and heavy rainfall leads to intense chemical weathering and leaching. These conditions facilitate the removal of specific minerals from the soil profile while concentrating others.

Analysis of Options:

• Desilication (Correct): This process involves the removal of silica (SiO₂) from the soil. Under conditions of high rainfall and temperature, silica becomes soluble and is leached away by percolating water. This leaves behind soils rich in iron and aluminium oxides, a process closely associated with laterization.
• Calcification (Incorrect): This refers to the accumulation of calcium carbonate in the soil layers. It typically occurs in arid and semi-arid regions where evaporation exceeds precipitation, preventing the leaching of carbonates.
• Salinization (Incorrect): This is the accumulation of water-soluble salts (such as sodium, potassium, and magnesium) in the soil. It is characteristic of arid regions or areas with poor drainage and high evaporation rates.
• Humification (Incorrect): This is the process of decomposing organic matter into humus. While it occurs in various climates, it refers to organic transformation rather than the leaching of mineral silica.

Key Takeaway: Desilication is the dominant pedogenic process in hot, wet equatorial regions, resulting in the loss of silica and the concentration of sesquioxides (iron and aluminium) in the soil.