Soil Moisture and Soil Water Infrastructure

What is the best measure of moisture?

Determining the optimum moisture level for plant growth and soil health is a crucial aspect of soil management. Various methods are available to measure soil moisture, each with its strengths and limitations.

Volumetric Moisture Content

Expresses moisture as a percentage of the soil volume.
Accurate and widely used in research and precision agriculture.
Requires specialized equipment, such as time domain reflectometry (TDR) or capacitance probes.

Gravimetric Moisture Content

Measures moisture as a percentage of the soil weight.
Straightforward and inexpensive, requiring only drying and weighing of soil samples.
Less sensitive to small changes in moisture content compared to volumetric methods.

Tensiometer

Measures soil water tension, which indicates the force with which water is held in the soil.
Provides a continuous record of soil water status.
Requires careful calibration and maintenance.

Neutron Probe

Uses a radioactive source to measure the moderation of neutrons in the soil.
Provides deep soil moisture measurements in situ.
Requires specialized equipment and safety precautions.

Soil Water Potential

Measures the free energy of soil water, which reflects both soil moisture and solute concentration.
Useful for studying water movement and plant-water relations.
Requires specialized equipment, such as tensiometers or pressure plates.

The choice of soil moisture measurement method depends on the accuracy and resolution required, the depth of soil to be measured, and the availability of resources. A combination of methods may be used to obtain a comprehensive understanding of soil moisture dynamics.