Question

The soil having the maximum water holding capacity is:

• A. Clayey
• B. Sandy
• C. Loamy
• D. Gravelly

Hint:

Water holding capacity is inversely related to particle size. The smaller the soil particles, the larger the surface area and the higher the water holding capacity. The order is: Clay>Silt>Loam>Sand>Gravel.

Answer 1

The Correct Option is A

Step 1: Relate water holding capacity to soil properties. Water holding capacity is the ability of a soil to hold water against the force of gravity. It is primarily determined by the soil's texture, which dictates the size and number of pores, and the total surface area of the soil particles.
Step 2: Compare the properties of the given soil types.
- Gravelly and Sandy soils: Have large particles, large pore spaces (macropores), and low surface area. Water drains through them very quickly, resulting in low water holding capacity.
- Loamy soils: A mixture of sand, silt, and clay, having a moderate water holding capacity.
- Clayey soils: Composed of very fine particles (\textless 0.002 mm). This results in a vast number of small pore spaces (micropores) and an extremely large total surface area. These properties allow clay soils to hold a large amount of water through adhesion and cohesion.
Step 3: Conclude which soil has the maximum capacity. Due to its fine texture, large surface area, and micropore structure, clayey soil has the highest water holding capacity among the given options.