What are the Different Types of Soil Water

Despite the fact that soil particles are frequently close to one another, there is always some angular space between them. Pore space is a term used to refer to all of these spaces in the soil as a whole.The pore space in the soil is a relatively constant volume (40-60 percent of the total soil volume) that remains filled with water and gasses in different proportions throughout its life cycle. In a “dry” soil, water occupies a very small proportion of the total amount of space available for plant growth. The majority of the available area in a “wet” soil is taken up by water. The soil, in fact, serves as a reservoir for the water required by plants.The ability of soil to retain moisture that would otherwise be available for plant growth and development for functions such as irrigation and land use is a critical component in plant growth and development. One of the most important tasks of soil is to collect and hold water during periods of heavy rainfall and to store it for later use.

Types

Soil water can be categorised into three categories based on the interaction of water molecules with the soil – aqueous, saline, and acidic.

• Water that is attracted by gravity
• Water in the capillaries
• Water with a high hygroscopicity
• Soil Water – Different Types
• Water that is attracted by gravity

Gravitational water

This is a free-flowing kind of water that is only weakly held in the soil. Gravitational force has the potential to readily remove this water. The macropores of the soil are the most common location for them. Unless the soil is particularly compact, just a small amount of gravitational water is made accessible to plants since they swiftly drain water down the table in all but the most compact of soils. As a result, plants are unable to utilise as much water as they would otherwise since they are moving swiftly out of the soil.

Capillary water

It is the water that is contained within the soil’s micropores, or more specifically, within the soil pore spaces. This water, which is what makes up the soil solution, is held loosely in place around the soil particles. This type of water is the most readily available to plants for use since it is the most readily available water form. Because plants are imprisoned in the soil solution, it is the primary source of water available to them. Capillary action (force) is responsible for the retention of capillary water in the soil, which is less than the atmospheric pressure.

Because the soil micropores’ surface tension qualities (adhesion and cohesion) are greater than the gravitational attraction or gravitational force, capillary water is held in the soil as a result. Nonetheless, because soil has a tendency to dry out, the size of the pore expands, and gravity begins to convert the capillary water into gravitational water, causing it to flow downward.

Hygroscopic Water

This type of water creates a fine layer over water particles, and it is often not readily available to plants due to its low availability. It can be found not just in soil pores, but also on the surfaces of soil particles, indicating that it is ubiquitous. These are strongly bound to the soil and cannot be removed except by drying the soil to 105 degrees Celsius.

Because of the adhesion capabilities of soil, hygroscopic water is tightly attached to it, resulting in some water being eaten solely by the roots of plants. Due to the fact that this type of water is found on soil particles rather than in pores, only certain types of soils with numerous pores (such as clays) will have a significant amount of it.

Chemically Combined Water

Water is present in the chemical compounds found in the soil particles because they are water-soluble. Chemically mixed water is the term used to describe this. The plants are likewise unable to use this resource.

Atmospheric Humidity

Because of the presence of hygroscopic hairs and spongy velamen tissues, the epiphytes’ hanging roots are able to collect moisture from the surrounding air.

Soil Layers and Substrates

The soil profile is made up of a succession of horizons or layers of soil that are stacked one on top of the other to form a layered structure. The letters O, A, E, C, B, and R are used to indicate the various strata or horizons.

The O-Horizon is a directional indicator.

When it comes to soil, the O horizon is the uppermost layer of topsoil that is primarily formed of organic elements such as dried leaves, dead leaves, small rocks, twigs, surface creatures, fallen trees, and other decomposed organic matter. This horizon of soil is frequently black brown or dark brown in colour, and this is mostly due to the presence of organic matter in the soil profile.

The A-Horizon, often known as topsoil

The humus layer is a stratum of the earth that contains a high concentration of organic material. This layer is made up of organic stuff as well as other degraded materials, such as wood. The topsoil is soft and porous, allowing it to retain sufficient amounts of air and water.

This layer is responsible for the germination of seeds and the formation of new roots, which eventually result in the formation of a new plant. This layer is made up of microorganisms such as earthworms, fungi, bacteria, and other microbes.

The E-Horizon is a directional indicator.

This layer is made up of nutrients that have leached out of the O and A horizons, respectively. This layer is more widespread in forested areas and contains less clay than the previous layer.

The B-Horizon, often known as the subsoil

It is the subsurface horizon, which is found immediately below the topsoil and above the bedrock. It is also known as the subsurface zone. It is tougher and more compact than topsoil, and it has a longer shelf life. It has a lower concentration of humus, soluble minerals, and organic materials. It is a place where certain minerals and metal salts, such as iron oxide, are deposited and formed.

Because of the presence of clay soil, this layer retains more water than the topsoil and has a lighter brown colour than the topsoil. When plowing the fields, the dirt from horizon-A and horizon-B is frequently mixed together.

The C-Horizon, also known as the Saprolite

Unlike the previous layers, this one is devoid of biological stuff and is composed entirely of shattered bedrock. The saprolite layer is another name for this stratum. The geological material found in this zone has been bonded together.

The R-Horizon is a directional indicator.

It is a layer that has been compacted and cemented. Granite, basalt, and limestone are among the different types of rocks that may be found here.

Conclusion

Soil water is responsible for transporting food ingredients necessary for plant growth.The amount of moisture in the soil impacts the yield of a crop in a certain region.It is essential in maintaining the temperature of the soil.Moisture in the soil serves as a source of nutrients.It is necessary for the production of soil.A moist soil is suitable for the growth of a wide variety of plants that require a large amount of water (Ex: Rice)The biological activities of soil microorganisms are catalysed by moisture in the soil.Photosynthesis in plants is dependent on water as its principal energy source.