Which of the following type of soil has the highest water retaining capacity?

1. Analyze the question You are asked which soil type holds the most water (highest water retention capacity). This depends on particle size and pore spaces.

2. Explain the concept

• Particle size: Clay has the smallest particles (less than 0.002 mm), silt is medium, and sand has the largest (0.05 to 2 mm).
• Pore spaces: Small particles pack tightly and leave very tiny pore spaces. These tiny spaces hold water by capillary action and surface adhesion, so the water is held strongly and does not drain away quickly.
• Large particles (sand): These leave big gaps, so water drains through quickly (high drainage, low retention).

3. Step-by-step solution

• Sand (D): Coarse particles and large pores give very fast drainage and the lowest water retention.
• Loam (A): A mixture of sand, silt and clay. It retains a moderate amount of water and drains well, which makes it ideal for farming but not the highest in retention.
• Laterite (B): A reddish, iron- and aluminium-rich soil, typically porous and well drained in the tropics. It is not known for high water retention.
• Clay (C): The finest particles with the tiniest pores, so it holds the most water. It is often waterlogged and poorly drained.

4. Answer The soil with the highest water retaining capacity is Clay, option C.

5. Exam tip Remember: "Smaller particles, more water."

• Clay: highest water retention, poorest drainage and aeration.
• Sand: lowest water retention, best drainage.
• Loam: a balanced soil in between.

Questions on soil also often ask about capillarity, so remember that clay has the highest capillarity (water rises through its tiny pores), while sand drains the fastest.