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Soil water characteristic

Video: The principle of the measurement: illustration experiment (50 sec)
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Video: Sampling and preparation (38 sec.)
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Measurement of the soil water characteristic
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Parametrization of the soil water characteristic
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The water retention curve defines the relationship between the water saturation (water content) and the pressure in the soil water. It is characteristic for a given soil and allows to infer the pore size distribution. A moist soil sample is put on a water-saturated ceramic plate in a closed pressure chamber. The water reservoir below the porous plate is connected to the atmosphere, keeping the pressure in the soil water at atmospheric pressure. Increasing the air pressure in the chamber increases the pressure difference between soil water and soil air.

The pressure inside the chamber is stepwise increased, which stepwise drains the sample. After each step, the sample is weighted. The chamber pressure is then plotted against water content (water saturation). This defines water retention curve. The term soil moisture characteristic is a synonym for the water retention curve.

 

 

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