Tensiometers are soil water measuring devices that are sensitive to soil water change and useful for irrigation scheduling. Irrigation scheduling is a process to determine when to irrigate and how much water to apply. Applying too little or too much water in an untimely manner can result in yield reductions. Over irrigation wastes water, costs money to pump, and may leach nutrients beyond the root zone. Irrigation scheduling is important and can be achieved by monitoring soil water status with tensiometers.
Plant roots undergo tension as they pull the water out of a soil matrix.
Tensiometers are devices that measure the soil water tension by acting like a mechanical root. This mechanical root is equipped with a gauge that continuously registers how hard the root must work to extract water from soil. Tensiometers are particularly accurate at low tensions, which is the wettest part of the soil water range. They are popular with growers of high-value crops, such as vegetables and fruits on sandy soils. A tensiometer is a sealed, water-filled tube equipped with a vacuum gauge on the upper end and a porous ceramic tip on the lower end.