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

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A small-scale matric potential sensor based on time domain reflectometry. / Persson, Magnus; Wraith, JM; Dahlin, Torleif.

In: Soil Science Society of America Journal, Vol. 70, No. 2, 2006, p. 533-536.

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T1 - A small-scale matric potential sensor based on time domain reflectometry

AU - Persson, Magnus

AU - Wraith, JM

AU - Dahlin, Torleif

PY - 2006

Y1 - 2006

N2 - 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.

AB - 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.

U2 - 10.2136/sssaj2005.0209N

DO - 10.2136/sssaj2005.0209N

M3 - Article

VL - 70

SP - 533

EP - 536

JO - Soil Science Society of America Journal

JF - Soil Science Society of America Journal

SN - 0361-5995

IS - 2

ER -