Question

The water held tightly to the surface of soil particles by adsorptive forces is called:

• A. Capillary water
• B. Hygroscopic water
• C. Gravitational water
• D. Free water

Hint:

Think of soil water in terms of availability to plants: - \textbf{Gravitational water:} Drains away too quickly. - \textbf{Hygroscopic water:} Held too tightly. - \textbf{Capillary water:} Just right (this is the "plant available water").

Answer 1

The Correct Option is B

Step 1: Define the different forms of soil water.
Soil water is classified based on how it is held in the soil pores.
- Gravitational water: Water that drains freely from the soil under the influence of gravity.
- Capillary water: Water held in the micropores of the soil by surface tension (capillary forces). This is the primary water source for plants.
- Hygroscopic water: Water that forms a very thin film around individual soil particles and is held so tightly by adhesion and adsorption forces that it is unavailable to plants.
Step 2: Match the definition to the question. The question describes water "held tightly to the surface of soil particles by adsorptive forces." This directly corresponds to the definition of hygroscopic water. This water can only be removed by heating the soil.