Determination Of Water Content Of Soil By Oven Drying Method

The water content also called moisture content is the amount of water present in the soil. In this blog post, we discuss the determination of the water content of soil by the oven drying method.

Water Content Of Soil

The water content of the soil is defined as the ratio of the mass of water to the mass of solids. The water content of the soil is expressed as small w.

The water content of the soil is represented in the percentage.

Thus the water content of the soil formula is w = (M_w / M_s) .100

The water content in the soil is very important because the behavior of the soil is controlled by the water content which is present in the soil.

The moisture content in the soil is determined by seven methods which are listed below.

Methods Of Determining Water Content In Soil

1. Oven Drying Method
2. Sand Bath Method
3. Pycnometer Method
4. Alcohol Method
5. Radiation Method
6. Calcium Carbide Method
7. Torsion Method

Let’s talk about the determination of water content through the Oven Drying Method.

Oven Drying Method

The oven-drying method is the laboratory method that is widely used for the moisture content determination of soil.

The determination of the water content of soil by the oven drying method is a very simple and accurate process.

Apparatus Required for Oven Dry Method

• Weighing balance.
• Oven with temperature 110^o± 5^o C.
• Air-tight container of non-corrodible material with a lid.
• Tongs.
• Desiccator.

Procedure Of Oven Dry Method

1. The first step is collecting moist soil samples by removing the top layer of soil. The soil sample quantity depends on the gradation, maximum size of soil particles, and degree of wetness.

2. Now the empty container is weighted as M₁.

3. The moist soil sample is put into an empty container and weighted as M₂.

4. The container with moist soil ( inorganic soil ) sample is placed in the oven and set the oven temperature at 110^o± 5^o C for 24 hours to complete the evaporation of water but the temperature for the organic soil is about 60^o-80^o C.

5. After 24 hours the oven is turned off and the container is taken out from the oven using tongs.

6. After Around one hour leave the container to cool down and after cooling down, the container is weighed as M₃.

Observations Table For Oven Drying

S.No.	Sample	Trial 1	Trial 2	Trial 3
1	M1 mass of the empty container	–	–	–
2	M2 mass of the container with moist soil	–	–	–
3	M3 mass of the container with dry soil	–	–	–

Calculations

The calculations of water content are done from the following equation-

The formula for calculation of water content through the oven-drying is w= (M₂-M₃ / M₃-M₁).100.

Here w is water content, M₂ is the mass of the container with moist soil, M₁ is the mass of the empty container, and M₃ is the mass of the container with dry soil.

Calculations Table

S.No.	Sample	Trial 1	Trial 2	Trial 3
	w= (M2-M3 / M3-M1).100	-%	-%	-%

Result- The natural moisture content of the soil sample is—

Advantages Of The Oven Drying Method

The main advantage of the oven drying method for water content determination of soil is that this method has a very simple procedure and there is no need for more technical knowledge to perform oven drying experiments.

And the oven-drying method gives a very accurate value of the water content of the soil.

Disadvantages Of Oven Drying Method

The main disadvantage of the oven drying method for water content determination of soil is it takes more time around 24 hours to get the amount of the water content of the soil.

In the oven drying if the temperature is below or above 110^o± 5^o C then it may break down the crystalline structure of soil or not cause complete evaporation of water.

It is not portable because the size of the oven is big, and it is heavy too.

Frequently Asked Questions(FAQ)