Water Absorption in Soil: An Experiment and Percolation Rate

Water absorption in the soil is a dynamic mechanism that is helpful in the water uptake of plant roots. Sandy soil is known to aerate but not retain water and has coarser or larger soil particles. Very little aeration and water-holding colloidal particles can be found in clay soils. There is no water between the big rocks. In reality, soil composed of rock particles with no water between them does not promote the proper growth of the root system. 

• This is because the soil can retain water. 
• Most water is retained by loam soil. 
• The capillary gaps and aeration in the loam are sufficient to hold water. 
• The components of humus are sand, clay, and organic material. 
• This soil is regarded as the greatest soil for plant growth since it can hold a lot of water. 
• How well soil absorbs water depends on several factors, including the rate of infiltration, permeability, percolation, and many others.

Key Words: Water absorption, Water, Soil, Sandy soil, Clay soil, loam soil, Percolation, Absorption

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Soil and its Formation

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Soil is generally understood to be the mixture of inorganic and organic components found on the earth's surface. There are different types of soil, including loam, clay sand, silt, and others. Different-sized fine rock fragments make up soil. They are made from sedimentary and worn igneous rocks, which have been subjected to the effects of wind, rain, heat, cold, and other natural variables. As a result, the rock fragments disintegrated into smaller ones, which eventually accumulated on flat or shallow areas to form soil. On this planet, soil formation has been occurring for billions of years and appears to be an ongoing process that will last as long as this planet does.

Soil and its Formation

• Moreover, soil is one of the most significant natural resources.
• Because soil sustains life by delivering water and nutrients to plants and a variety of other living things. 
• Because it serves as the foundation for all agricultural activities. 
• It also provides nourishment for both people and other animals. 
• Soil is that aspect of our existence that is inextricably linked to us.

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Percolation Rate of Water in the Soil

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Percolation is the term used to describe the process of any liquid passing extremely slowly through a substance with tiny pores. So, the slow movement of water out of the soil is referred to as percolation.

• Depending on the kind of soil, different soils absorb water at different rates. 
• The pace at which water percolates through each soil type also varies.
• Because each form of soil has a unique composition,
• The soil can store the water for a longer amount of time if its percolation rate is high.
• In contrast, a low soil percolation rate indicates that the soil will only be able to store the water for a limited time.

Soil Percolation

Percolation Summary

Percolation is therefore - 

• A characteristic of how soil absorbs water.
• The water on the floor will flow down if we dump a bottle of water on the floor.
• But the water that goes in the soil will be absorbed.
• The amount of water absorbed by any soil at any particular time is known as the percolation rate.

The formula for percolation of soil

The formula for percolation of soil is as below

Percolation Rate (ml/min) = amount of water (ml)Percolation time (minutes)

The rate can be computed as follows;

If 200 ml of water percolates through the soil sample in 40 minutes. 

The fact is, using the formula provided above, 200 ml40 minutes = 5 ml/min

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Absorption of Water in the Soil

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Many varieties of soil have different capacities for absorbing water, just like soil percolation rates do. The soil's ability to absorb water is referred to as its water absorption capacity. The formula (U-V) gm. It can be used to calculate how much water is absorbed by soil: where U stands for initial water weight and V for final water weight.

Absorption of Water in Sandy Soil

Sandy soil contains very tiny rocks, which are meant for aeration but not for water retention. Clay soils are very poorly aerated despite having colloidal particles that may store water. There is no water held between the large granite fragments. The growth of a root system is not expected in any soil with rock particles that do not hold water in between them. This is due to the soil's appalling ability to hold water.

Absorption of Water in Loam Soil

Loam is the type of soil that holds the most water. Sand, clay, humus, and decayed organic material, are present in loam because these materials help the soil retain water by creating adequate capillary gaps and efficient aeration. Thus, because it has a good capacity for keeping water, this soil is regarded as the best for the growth of plants. The amount of water that soil can absorb depends on a variety of different variables, including permeability, infiltration rate, percolation, and more.

Water in Soil

The soil contains water in five different forms. These are water vapours, combined water, capillary water, hygroscopic water, and gravitational water. Irrigation or rainfall are the primary sources of all soil water. A small amount of precipitation is drained away from the soil's surface along the slope rather than entering the ground. It is also referred to as run-off or run-away water.

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Experiment on the Absorption of Water by Soil Procedure

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Get filter paper and a plastic funnel (else, a piece of newspaper sheet). Pour 50 grams of dry, powdered soil into the funnel after weighing it. Using a measuring cylinder, now measure a specific amount of water and apply it to the soil drop by drop. For this procedure, a dropper can also be used. Also, keep in mind not to concentrate on the waterfall at one location. Water should be applied evenly to the soil, and should be continued until it begins to drip. Subtract the quantity of water that is still in the measuring cylinder from the initial dose. The amount of water that is retained by the soil is the end consequence. In the method outlined below, record the findings in a notebook.

Calculation

Water absorption can be calculated as follows;

Weight of soil = 50 gm

The initial volume of water in the measuring cylinder = U ml

The final volume of water in the measuring cylinder = V ml

The volume of water that is absorbed by the soil = (U – V) ml

Weight of water absorbed by the soil = (U – V) g (1 ml of water has a weight that is equal to 1 gm) a percentage of water absorbed.

= (U-V)50 X 100

Here 50g is the amount of water that has been absorbed.

The experiment can be repeated using various soil samples. It gives an idea about which types of soil have the highest and lowest percolation rates as well as which types simultaneously retain the most and least water. It also gives information about various soils.

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Things to Remember

• Water absorption in soil depends on the type of soil.
• Soil minerals are created from rocks by weathering and erosive forces of nature.
• Sand, silt, and clay are the three size-related types of soil-forming particles.
• The majority of crop plants thrive in loamy soil because it retains a lot of moisture and air.
• Four categories of soil moisture are gravitational water, capillary water, hygroscopic water, and water vapour.
• The process through which soil absorbs water is known as percolation.
• Percolation makes water move downward through the minuscule spaces between rocks and soil particles.
• Percolation Rate (ml/min) = amount of water (ml)Percolation time (minutes)