Soil moisture determination using the dielectric sensor TDR300 in porous media with increased salinity

In the present study, the impact of bulk soil electrical conductivity (EC_b) on water content determination using the dielectric sensor TDR300 was investigated in a sandy porous medium.
The study included different water content regimes varying from completely dry to saturation, as well as several electrical conductivity levels of wetting solution (EC_w). It was shown that the relation between volumetric water content (θ) and the square root of relative dielectric permittivity (ε_r) was linear up to 0.5 dS m^-1 of EC_b. It was also proved that for EC_b values exceeding 0.5 dS m^-1, the relationship between θ and logarithmic dielectric permittivity becomes linear.
Thus it is apparent that apart from the water content and permittivity values, the bulk electrical conductivity value is necessary to obtain correct water content measurements.
In conclusion, the accurate determination of porous media water content using TDR300 dielectric sensor can be resolved relatively easily even at high electrical conductivity values using the porous media specific calibration.

VI International Conference on Landscape and Urban Horticulture

G. Kargas, N. Ntoulas, P.A. Nektarios, A. Kladou

calibration, bulk electrical conductivity, dielectric permittivity

https://doi.org/10.17660/ActaHortic.2017.1189.51