Analysis of the saturated unsaturated hydraulic conductivity in a mixed sodium calcium soil system

Russo, D.; Bresler, E.

Soil Science Society of America Journal 41(4): 706-710


ISSN/ISBN: 0361-5995
DOI: 10.2136/sssaj1977.03615995004100040017x
Accession: 004744253

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A model is developed to diagnose the effect of Na/(Ca)1/2 ratios and soil solution concentrations on the hydraulic conductivity for an unsaturated soil. The model takes into account the porous nature and the electrical properties of the soil. Interactions between ions in the exchange phase and in the liquid phase are expressed quantitatively by the diffuse double-layer theory. Experimental data on the effect of soil solution and soil-water pressure on clay-platelet organization and structure were considered in the model. A test is made of the sensitivity of the model to variations in the various input parameters. The model is found to be sensitive to the relationship between the number of platelets per clay particle, and the ESP [Exchangeable Sodium Percentage] of the soil. The diagnostic model is compared with experimental data for 3 soils of different texture. The model approximates the hydraulic conductivity function for many practical combinations of Na/(Ca)1/2 ratios and soil solution concentrations for the ranges of soil water content in which most of the water flow occurs.