• Skierucha, W.
• Szerement, J.
• Szypłowska, A.
• Lewandowski, Arkadiusz
• Kafarski, M.
• Wilczek, A.
• Włoszczyk, Aleksandra

Abstract

Dielectric sensors operating in time and frequency domain can be used to determine soil moisture content. There isstill a need for developing new sensors for determination of soil water content, in order to further improve measurementaccuracy, lower the price or adapt the equipment for specialapplications. For example, many of the existing soil moisture probes do not allow accurate measurement of dielectric properties in a small volume because of their construction. The paper presents the evaluation of a seven-rod probe for an accurate determination of soil water content in a small sample volume. Firstly, digital simulations for sensitivity zone of the tested probe were performed. Next, the prototype probe was tested for two soils with various texture and moisture content inthe range from air dry to near saturation. The values ofdielectric permittivity (frequency domain) and apparentdielectric permittivity (time domain) were calculated from the measured S11 parameters. The obtained data was comparedwith the reference Topp’s equation. It was concluded that the tested probe is able to measure soil moisture in a small volume(about 8 cm3) in the range of frequencies from 20 MHz to 200 MHz.

Topics

• impedance spectroscopy
• simulation
• texture