Soil Salinity and Sodicity Impacts on Soil Hydrologic Properties.

Soil salinity and sodicity are problematic in North Dakota from ground waters and soil parent materials high in soluble salts and sodium. Our objective was to evaluate solution salinity and sodicity impacts on soil hydraulic properties during simulated groundwater wetting. Four soil types were saturated from below with salt solutions of varying electrical conductivity (EC) and sodium adsorption ratio (SAR) values. The saturated and unsaturated hydraulic conductivities and water retention were then measured on these soils. Hydrologic properties were fitted with the van Genuchten and dual porosity water retention models. Soil hydrologic properties were affected by salt solution composition only when soils were near saturation, as expected. The water retention models described the measured data well and were similar across solution compositions when multiple measurement methods were used.  However, model fits began to deviate when some measurement methods were excluded for soils containing either high sand content or high levels of solution EC.