A small-scale matric potential sensor based on time domain reflectometry

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Measurements of soil matric potential (Psi) are needed in many soil science applications. In the present study, a small matric potential sensor having a length of 30 mm and a diameter of 9.6 mm was developed. The sensor consists of two coils made of lacquer-coated copper wires embedded in gypsum. The dielectric constant of the gypsum (K-gypsum) was measured with time domain reflectometry (TDR). The gypsum probes were tested in a sandy loam soil using a pressure extractor to obtain the relationship between K-gypsum and Psi, allowing inference of the soil Psi in equilibrium with the sensor. It was shown that the gypsum probe could give Psi estimates with a root mean square error (RMSE) of around 50 kPa in the range of -20 to -1500 kPa. Most of the sensitivity of the sensor was in the -50- to -1000-kPa range.


Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Water Engineering
  • Geotechnical Engineering
Original languageEnglish
Pages (from-to)533-536
JournalSoil Science Society of America Journal
Issue number2
Publication statusPublished - 2006
Publication categoryResearch

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