Question

What are the forms in which water occurs in the soil?

Answer 1

Hint: Water found in the naturally occurring soil is known as soil water. There are three main types of water occurring in the soil. These types are defined based on the function of the water in the soil. The three types are:
1. Gravitational water
2. Capillary water
3. Hygroscopic water

Complete answer:
Gravitational water: By the force of gravity there is free water moving through soil known as gravitational water. It is found in macro-pores of the soil and very little of it is available to plants as it drains rapidly down the water table in all except the most compact of the soil.
Capillary water: Water held in the micro-pores of the soil is the capillary water. This water composes the soil solution. Because of the surface tension properties (cohesion and adhesion), this capillary water is held in the soil. Cohesion and adhesion are stronger than force of gravity. This water is the main water available to the plants as it is trapped in the soil solution right next to the roots in the plant.
Hygroscopic water: This water is generally not available to the plant. It forms a very thin film surrounding the soil particles. Very little of this water can be taken up by roots as it is bound so tightly to the soil by adhesion properties. This water is found on the soil particles and not in the pores, so certain kinds of soils with few pores contain a higher percentage of hygroscopic water.

Note:
For both plants and soil organisms, water supply through soils is vital. They need water to survive. Soil water is full of nutrients that move into the plant roots when plants take in water. This water enters the soil through large pores called macropores and is stored in many small pores called micropores. For a healthy and productive soil, water is an essential nutrient. Water serves to bind the physical particles in soil structure and it is the medium by which natural chemicals and essential trace element nutrients are transported to plants.