Question

What are the different types of water?

Answer 1

The different types of water present in soil can be classified as:

1. Gravitational water: The water which percolates deep in the soil, due to gravity is called ‘gravitational water’. This water goes beyond the reach of roots of most of the plants, thus is not available to plants for absorption.
2. Hygroscopic water: Hygroscopic water refers to the thin film of water that tightly adheres to soil particles due to adsorption forces. This type of water is usually not available to plants because it is held too firmly by the soil particles. Hygroscopic water is the moisture that clings to the surface of soil particles through adsorption. 
3. Combined water: Water present in the form of hydrated oxides of silicon, aluminium, etc., is called ‘combined water’. It is also not available to plants for absorption.
4. Capillary Water: Capillary water refers to the moisture that is retained in the soil and is held around the soil particles by capillary forces. This type of water is essential for plant growth as it is the primary source of water available to plant roots. Capillary water is the water that remains in the soil after gravitational water has drained away. It is held in the small pores of the soil due to surface tension and adhesion to soil particles.