Ronny Berndtsson
Professor, Dep Director, MECW Dep Scientific Coordinator
Soil water content and salinity determination using different dielectric methods in saline gypsiferous soil
Author
Summary, in English
Abstract in Undetermined
Measurements of dielectric permittivity and electrical conductivity were taken in a saline gypsiferous soil collected from southern Tunisia. Both time domain reflectometry (TDR) and the new WET sensor based on frequency domain reflectometry (FDR) were used. Seven different moistening solutions were used with electrical conductivities of 0.0053-14 dS m(-1). Different models for describing the observed relationships between dielectric permittivity (K-a) and water content (theta), and bulk electrical conductivity (ECa) and pore water electrical conductivity (ECp) were tested and evaluated. The commonly used K-a-theta models by Topp et al. (1980) and Ledieu et al. (1986) cannot be recommended for the WET sensor. With these models, the RMSE and the mean relative error of the predicted theta were about 0.04 m(3) m(-3) and 19% for TDR and 0.08 m(3) m(-3) and 54% for WET sensor measurements, respectively. Using the Hilhorst (2000) model for ECp predictions, the RMSE was 1.16 dS m(-1) and 4.15 dS m(-1) using TDR and the WET sensor, respectively. The WET sensor could give similar accuracy to TDR if calibrated values of the soil parameter were used instead of standard values.
Measurements of dielectric permittivity and electrical conductivity were taken in a saline gypsiferous soil collected from southern Tunisia. Both time domain reflectometry (TDR) and the new WET sensor based on frequency domain reflectometry (FDR) were used. Seven different moistening solutions were used with electrical conductivities of 0.0053-14 dS m(-1). Different models for describing the observed relationships between dielectric permittivity (K-a) and water content (theta), and bulk electrical conductivity (ECa) and pore water electrical conductivity (ECp) were tested and evaluated. The commonly used K-a-theta models by Topp et al. (1980) and Ledieu et al. (1986) cannot be recommended for the WET sensor. With these models, the RMSE and the mean relative error of the predicted theta were about 0.04 m(3) m(-3) and 19% for TDR and 0.08 m(3) m(-3) and 54% for WET sensor measurements, respectively. Using the Hilhorst (2000) model for ECp predictions, the RMSE was 1.16 dS m(-1) and 4.15 dS m(-1) using TDR and the WET sensor, respectively. The WET sensor could give similar accuracy to TDR if calibrated values of the soil parameter were used instead of standard values.
Department/s
- Division of Water Resources Engineering
Publishing year
2008
Language
English
Pages
253-265
Publication/Series
Hydrological Sciences Journal
Volume
53
Issue
1
Document type
Journal article
Publisher
Taylor & Francis
Topic
- Water Engineering
Keywords
- soil salinity
- gypsiferous soils
- time domain reflectometry (TDR)
- frequency domain reflectometry (FDR)
Status
Published
ISBN/ISSN/Other
- ISSN: 0262-6667