T8 Manual - UMS

Useful notes
If there will be rain before the soils reaches -15 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, after day
20).
Interpretation Interpretation Messwerte of readings unter below 10 bar 10 in bars tieferen
Bodenschichten
in a greater depth
10000
Soil water Wasserspannung
tension (hPa)
1000
100
10
Soil Bodenwasserspannung
water tension
Tensiometermesswert reading
1
0 5 10 15 20 25 30 35
Time Zeit
Abb. 7.2 Tensiometer readings with tensions to -10 bars
Other problems that can be recognized by checking the data:
Soil water tension 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 malfunction.
With T8 and T4e Tensiometers, unsteady signals might also be
caused by solar radiation on the refilling tubes. This would require
the use of thermal insulation - see chapter 3.1.4.
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