Addendum; Typical Measuring Curves - UMS HYPROP Operation Manual

Addendum

Typical measuring curves

The following typical curves were kindly provided by Prof. Dr. Wolfgang Durner.
Sandy loam (Ls3)
Site: Wolfenbüttel; soil type: slightly sandy loam. Ls3 (S 35%, U 48%, T 17%); measurements in win-
ter 2011 at "Geoökologische Labormethoden 2011", TUBraunschweig. Evaporation: 2,75 mm/d,
temperature: 21°C
Description of the measuring process
The measurement process is typical of clay with wide pore size distribution
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The water tensions rise almost two days continuously, but at a moderate slo-
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pe. This reflects large pore fraction in clay of almost 10%
From about 50 hPa (pF 1.7), the tensio shafts are far enough away to allow for
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the determination of hydraulic conductivities.
After two days the tensio shafts are now moving with a greater slope, but still a
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rather weak curvature continues. The measurement limit is already reached
a day later. This indicates a limited and simultaneously diversified porosity.
The spreading of tension values is moderate, which indicates a relatively high
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hydraulic conductivity in this area.
The measurement is completed by the (almost too early) failure of the upper
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tensio shaft after three days. At the time the sample is removed about 17%
water.
83 | Addendum