A new approach for estimating pore water electrical conductivity of saturated soils

Soil salinity is commonly assessed by measuring the electrical conductivity of the soil saturated paste extract, i.e., pore-water electrical conductivity of saturated soils (σ_ps), yet its accurate determination remains challenging. While Hilhorst (2000) established a linear relationship between bulk soil electrical conductivity (σ) and dielectric constant (K_a) using σ_ps as a parameter, its applicability across diverse soil textures requires further examination. The objectives of this study are to evaluate the σ-K_a relationship for σ_ps estimation σ_ps across a broad texture spectrum, and to develop a generalized relationship between the formation factor (F_s, the ratio of pore-water electrical conductivity σ_p and σ) and porosity (n) for σ_ps estimation at room temperature (25 ± 1 °C). The model was validated using independent datasets spanning clay content from 0 to 0.47 g g⁻¹ and σ_ps values from 0 to 20 dS m⁻¹. Comparing to exiting methods, the new approach achieved superior performance with an average root mean square error of 0.44 dS m⁻¹. The proposed method enables reliable σ_ps estimation using only n and saturated bulk electrical conductivity measurements, offering practical advantages for field-scale soil salinity monitoring.