Tensiometers for direct measurement of the soil water tension
All water movements in soils are directly depending on the soil water tension, as water - in soils as well as on surface - will always move from areas of higher potential to areas of lower potential.Main water movements occur at low tensions which only Tensiometers measure directly and precisely.
Naturally embedded soils are heterogeneous. Thus, soil water processes are not only affected by precipitation and evapotranspiration, but also by texture, grain size, cracks, compactness, aggregation, roots and cavities. Tensiometer measurements are not directly influenced by the soil heterogeneity.
How does it work?
pF / WC - correlation
Soil water and Tensiometer water have contact through the porous ceramic as a wetted porous ceramic creates an ideal pore/water interface. The soil water tension is directly conducted to the pressure transducer which offers a continuous signal. The atmospheric reference pressure is provided through a membrane on the cable, a distinctive patented method.
Taking spot readings with the INFIELD7
Measuring site at the Zurich airport
Applications
- Spot readings:
T1 or T3 - Low-cost-applications:
T1 or T3 - Irrigation control:
T3 - Environmental monitoring:
T4, T8 or TS1 - Lysimeter sites:
T4, T8 or TS1 - Punctiform, pot or laboratory measurements: T5
Benefits
- Tensiometers are functional up to 85 kPa, correspondingly pF 2.9
- The unique T5x can reach 200 kPa
- Tensiometers T1, T3, T4 and T5 have a common calibration: kPa = 0 mV to +85 kPa= +85 mV
- Tensiometers T8 and TS1 have an amplified linear signal output
Virtually unbreakable homogenous sinter ceramic cup on T4, T8
Limits
- T1, T3 and T5 must be protected from frost
- Dry soil draws off the water
Contact
Georg von UnoldTel: +49 89 12 66 52 - 15
Fax: +49 89 12 66 52 - 20
E-Mail: gvu@ums-muc.de
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