Volumetric Method of Soil Moisture Measurement

The volumetric method of soil moisture measurement is a straightforward and widely utilized technique for determining the water content of soil samples. This method involves the following steps:

Materials Required

  • Fresh soil sample
  • Weighing scale
  • Metal cans or weighing containers
  • Drying oven

Procedure

Step 1: Weighing the Soil Sample

An undisturbed soil sample is weighed using a weighing scale immediately after collection. This measurement represents the total weight of the soil sample, including both water and soil particles.

Step 2: Drying the Soil Sample

The soil sample is transferred into a metal can or weighing container. The container is then placed in a drying oven maintained at 105 degrees Celsius for 24 hours to evaporate all moisture.

Step 3: Reweighing the Soil Sample

After drying, the container and the dried soil sample are reweighed. This provides the dry weight of the soil.

Step 4: Calculating Soil Moisture Content

The soil moisture content is calculated by subtracting the dry weight from the initial weight of the soil sample and dividing the result by the dry weight. The formula for calculating volumetric moisture content (θ) is:

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θ = [(Weight of wet soil – Weight of dry soil) / Weight of dry soil] x 100%
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Advantages of Volumetric Method

  • Simple and straightforward
  • Does not require specialized equipment
  • Reliable and accurate
  • Suitable for a wide range of soil types

Applications

The volumetric method of soil moisture measurement finds applications in various fields, including:

  • Agriculture: Monitoring soil moisture levels for crop irrigation
  • Environmental science: Quantifying water availability in soil ecosystems
  • Geotechnical engineering: Evaluating soil stability and bearing capacity