How does the sensor station measure soil moisture?

How does the sensor station measure soil moisture?

We use Irrometer's Watermark sensors & Sentek's Drill & Drop sensors to measure moisture.

Each Watermark sensor station contains between up to 5 Irrometer Watermark soil moisture sensors, which have been used & trusted by growers for nearly 40 years. The sensors measure how hard the crop has to work to extract water out of the soil. They electronically read the amount of moisture absorbed through a special mix of precisely composed materials.

Each Sentek sensor station has a Sentek Drill & Drop probe that is capacitance-based & measures volumetric soil moisture. Volumetric soil moisture content is expressed as a percentage. Unlike the Watermark sensor, which measures soil moisture at a single location, the Sentek Drill & Drop probe measures soil moisture & soil temperature every 4" along the length of the probe, starting at 2". So, if you have a Drill & Drop probe that is 2 feet long, the sensor measures soil moisture & temperature at depths of 2", 6", 10", 14", 18", & 22".