Abstract
Tensiometers are instruments that measure the matrix potential or matrix tension of the soil. This is an indirect measure of soil moisture and is caused by the forces that hold water in the capillaries and on the soil particles.
When the soil dries, there is an increase in the matrix tension (the tensiometer reading rises), while when it is moistened, there is a decrease (the tensiometer reading drops), being able to reach values close to zero when the soil becomes saturated with Water.
A tensiometer consists of a tube that ends in a porous ceramic tip (ceramic capsule). The tube is completely filled with water and hermetically sealed at the top. During installation, the ceramic capsule is inserted into the ground, completely surrounded by soil particles and micropores. The ceramic communicates the water in the interior with the soil solution.