STELZNER® agricultural measurement systems

Analogue measurement of the suction tension

A tensiometer is used to measure suction tension. The porous cell of the tensiometer uses capillary action to transport water outwards into the drier soil. A negative pressure is then created within the closed pipe. This negative pressure is an indication of the moisture. Suction tension is a force measuring the tension with which the water is held to the soil or its availability.
Plant roots must expend this force in order to absorb water. The decisive factors in creating this force are the fine pores and capillaries in the soil. This soil characteristic which the tensiometer measures is critical for plant growth. One advantage this instrument has over electrical meters is that it does not need to be calibrated.

The value of the suction tension increases as long as the substratum is capable of transferring the water and as long as the moisture differential is maintained. If the surroundings become more moist, the the process reverses itself. Close contact with the substrate is needed to get a quick tensiometer reaction and to get a value for certain soil and substratum types.

The Blumat plug-in tensiometer is designed as a low-cost but stable probe (with a tube diameter
of 25 mm); it is designed to be used exclusively in combination with the digital manometer. It is a reliable moisture sensor for taking soil measurements at common depths for locations which are not too dry. (Also refer to the Premium plug-in tensiometer.)

Please order the digital manometer separately.