UMS T5 User Manual page 37

Useful notes
If there will be rain before the soils reaches -2 bars, the Tensiometer
cup will suck up the soil water. However, the soil water includes
dissolved gas which will degas as soon as a dry soil again will
increase the tension. This will result in a poor response, the signal
curve will get flatter and readings will only slowly adapt to the actual
soil water tension. Depending on the size of the developed bubble
readings will get less close to the maximum (fig. 7.2).
10000
1000
100
10
1
0 5
Fig. 7.2 Tensiometer readings with tensions below -2 bar
Soil water tensions normally change only slowly. Therefore, a signal
curve with lot of jumps could be an indicator for example for loose
contacts, moisture in defective cables or plugs, poor power supply or
data logger malfunctions.
Interpretation Messwerte unter 2 bar
Interpretation of readings below -2 bars
Soil water tension Bodenwasserspannung
Tensiometer reading
Tensiometermesswert
10 15
Time
37/48
20 25
Ze t i
30 35