Table of Contents
Advertisement
Useful notes
7 Useful notes
7.1 Maximum measuring range and data
interpretation
The measuring range of Tensiometers is limited by the boiling point
of water. At a temperature of 20°C the boiling point is at 2,3 kPa over
vacuum. So with 20°C and an atmospheric pressure of 95 kPa the
Tensiometer cannot measure a tension below -92,7 kPa, even if the
soils gets drier than that. The readings remain at a constant value
(fig. 7.1, between day 10 and 16).
Interpretation Messwerte bis über 15 bar nahe der
100000
10000
1000
100
10
1
0
2
Fig. 7.1: Tensiometer readings with tensions to -15 bars
If the soil will get even drier and reaches -15 bar, the ceramic's
bubble point is reached. The cup water will run out quickly and the
reading of the air filled cup will go to zero (fig. 7.1, day 16 to 19)
Interpretation of readings below 15 bars
and close to surface
Bodenoberfläche
Soil water tension
Tensiometer reading
4
6
8
Time
44/58
Bodenwasserspannung
Tensiometermesswert
10
12
14
Time
Zeit
16
18
20
Advertisement
Table of Contents
