Angular tensiometer

Structure and principle of operation of the apparatus: The mechanical tensiometer is made up of a plastic tube with a transparent part in its upper segment, whereas a porous ceramic dome is connected to its bottom end. Into its uppermost end is screwed a mechanical vacuum meter in the shape of a watch with a hand.

In the standard tensiometer of Ami Tens, the vacuum meter has a ¼” thread in the back which screws into a plastic adaptor within which there is a special seal that prevents the vacuum from leaking out of the apparatus. In order to fill in or add water, it is necessary to manually remove the vacuum meter and to close using force at the end of the procedure. The ceramic is inserted into the area of the roots whereas its outside is in close contact with the soil and its inside is in contact with the water in the tube. In order to install in detached substrates that are located in shallow vessels, or in any case in which one wants to measure a thin layer of soil, we provide an angular tensiometer (‘L’ configuration) in which the ceramic is in a horizontal position and is inserted laterally into the container into which the plant is planted. In cases in which the soil is especially permeable (e.g., coconut), it is possible to choose to use a ceramic with a length that is twice as long (12 cm). The dryer is the soil, the greater will be the tension of the water (sub-pressure) inside the tube and we read the data. The vacuum meter indicates the tension in units of negative pressure, that is, centibars in the following values: 0 -- for saturated soil, up to 100 -- for totally dry soil, or in millibars in the following values: 0 -- for saturated soil up to 250 -- for land that is totally dry. After irrigating or rain, the tension of the water will decrease. By following up continuously, the farmer can decide when and how much to irrigate in the most efficient manner.

Since the angular tensiometer enters laterally into the vessel in which the plant is planted, the length of the tube after the angle is fixed at 20 cm.