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.
This tensiometer has a measuring range from 0 to 600 mbar negative pressure. It comes optionally with an analogue pressure manometer (the Tensiometer Classic) or with a digital pressure sensor (the Tensiometer Digital). Additional versions and lengths are available on request.
It is possible to connect to the EMS 323 event reporting system (page 49) by using the Tensio Trans transmitter or the Tensio Swith transmitter.
Consisting of the EMS 232 event reporting system (article no. 4900), and the tensiometer (article no. 8061), article no. 8085 or the VH 400 soil sensor (article no. 8096).
4900 Event reporting system
8096 VH 400 soil sensor