Tensior T8 - Eijkelkamp Agrisearch Equipment

7.5 Length of the refilling tubes
Keep the refilling tubes as short as possible. Caused by the thermal expansion
of air, any air inside the tubes will affect the readings when temperature
changes. Preferably, insulate the refilling tubes or install them isothermal into
the soil.
7.6 Jacket tubes
Jacket tubes are useful with shafts longer than 2 m, in pebbly soils or gravel,
and for horizontal installations from inside a well or pit hole. The jacket tube
should end 30 to 50 cm away from the cup so leaking or condensation water is
not conducted to the cup. The inner diameter of the jacket tube should be at
least 35 mm.
7.7 Ideal condition for installation
For the installation of Tensiometers, the ideal conditions are:
- Frost-free soil.
- Coarse clay or loess.
- In soil types loess, coarse clay, loam or clay as well as in highly organic soils
(humus) preferably with a water tension close to saturation (moist).
- In sandy or pebbly soils with a water tension over 100 hPa (rather dry).
- Low skeletal structure (gravel). The more gravel in a soil the more often
the drilling has to be repeated to reach the required depth.
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