The Irrometer tensiometer measures the moisture tension in the soil by using a sealed water tube with a porous tip and vacuum gauge. The instrument acts as a "false root" by measuring a higher reading on the gauge as the soil dries and lower reading when irrigation or rain occurs. The Irrometer works the same on sandy soils as clay soils with no calibration needed. With the use of the Irrometer growers can save on water usage and be more precise with their water scheduling. Generally two different depth instruments are used per location as shown in the picture to monitor the moisture throughout the root zone. IRROMETER Model “SR” — has threaded replaceable tip, for general use with row, tree and field crops. * Includes reservoir, air free gauge chamber and hermetically sealed IRROMETER vacuum gauge with dual scale of centibars and kilopascals (0 -100 cb [kPa] range).