Description

This logger sensor is based on measuring the
vacuum pressure in a tensiometer. A tensiometer
is a closed tube with a special ceramic part in
its end. The tensiometer is filled with water and
put in the soil. If the soil is dry, water goes out by
diffusion through the ceramic holes and vacuum
pressure is created in the tensiometer. When
we wet the soil, the vacuum in the tensiometer
pulls water into the tensiometer and the vacuum
decreases. This is why soil moisture is measured
in pressure level.