### Theory:

When water is poured into the soil, the water will be absorbed by the soil to a certain extent. After saturation, water will not be absorbed further by the soil.

The quantity of water absorbed by the soil when a certain amount of water poured into the soil is its absorption capacity.

Absorption capacity of soil can be calculated using the following experiment.

Take a Plastic funnel and a filter paper or any newspaper. Place the folded filter paper inside the plastic funnel. Take a beaker and keep the funnel in it as shown in the figure. Take \(50\)g of soil and pour it on the filter paper. Now take some water in a measuring cylinder and note down the amount of water (U) in it and run it as drop by drop, all over the filter paper's soil. Until water started to flow out of the funnel, pour the water continuously.

After the experiment, note down the amount of water in the measurement cylinder( \(V\)).

Weight of soil = \(50g\)

Initial volume of water in the measuring cylinder in mL = U

Final volume of water in the measuring cylinder in mL = V

Therefore, the volume of water absorbed by the soil in mL = (U – V)

Weight of water absorbed by the soil in g = (U – V)

**Note:**(\(1\ mL\) of water has a weight equal to \(1\ g\))

Percentage of water absorbed = (U - V) / \(50\) × \(100\%\)

In general, we can write,

Percentage of water absorbed \(=\) \(\frac{(U-V)}{W}\times 100\%\)

where,

\(U\) - Mass of the initial volume of water in the measuring cylinder in g

\(V\) - Mass of final volume of water in the measuring cylinder in g

\(W\)- Mass of sand in g

Percentage of water absorbed \(=\) \(\frac{(U-V)}{W}\times 100\%\)

where,

\(U\) - Mass of the initial volume of water in the measuring cylinder in g

\(V\) - Mass of final volume of water in the measuring cylinder in g

\(W\)- Mass of sand in g

Volume of water absorbed by the soil {U-V [mL]} is the amount of water retained in the soil. If you do this experiment with different soils, the percentage of water absorbed will differ for each soil.

Lower percolation rate of soil has high water retention capacity and vice versa. Soil having a lower percolation rate can hold water for more time, i.e., the soil's absorption rate is high while soil with higher percolation rate can hold water for less time, i.e., the absorption rate is less.

Lower percolation rate of soil has high water retention capacity and vice versa. Soil having a lower percolation rate can hold water for more time, i.e., the soil's absorption rate is high while soil with higher percolation rate can hold water for less time, i.e., the absorption rate is less.