Chemical and physical behavior of two kentucky soils: III. Saturated hydraulic conductivity ‐imhoff cone test relationships

Abstract

Abstract Clay dispersion is considered to be one of the most pronounced causes for reduction in soil hydraulic conductivity. The purpose of this study was to establish the dispersion potential of two Kentucky soils (Pembroke and Uniontown) as a function of solution ionic strength, solution composition (sodium absorption ratio, SAR) and pH through the quantification of a dispersion index (DI) and related the latter to soil relative saturated hydraulic conductivity (RSHC). The study demonstrated that DI increased as the electrolyte concentration decreased and the sodium adsorption ratio (SAR) and pH increased. Furthermore, the DI of the Uniontown soil was more dependent on electrolyte concentration, and SAR changes, but less dependent on pH changes than that of the Pembroke soil. The relationship between RSHC and DI also appeared to be dependent on electrolyte concentration SAR and pH. These components were shown to regulate saturated hydraulic conductivity via two mechanisms: (1) clay dispersion and (2) clay swelling. Clay dispersion was associated more with the Pembroke soil while clay swelling was associated more with the Uniontown soil. These observations were consistent with the thermodynamic exchange parameters of these two soils.