Document Type : Research Article
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Abstract
With increasing population and scarcity of fresh water,one of possible solutions is, using marginal waters (saline and sodic water). Using marginal waters should be taken into consideration and special studies. Since most processes related to soil and water, take place in unsaturated field condition, The purpose of this research is evaluation of saline and sodic water effect on diffusivity and unsaturated hydraulic conductivity.for this purpose, two soil types include loamy and sandy, two levels of SAR, 5 and 20, two levels of EC, 4 and 12 ds/m and distilled water were used. NaCl, CaCl2 and MgCl2 salts at Ca:Mg=2:1 were used to prepare treatments. Diffusivity was measured by one step out flow method at the suction of 15 bar. Unsaturated hydraulic conductivity calculated by using the diffusivity and the slope of the soil moisture charactristic curve. At both soils with increasing SAR and decreasing EC, diffusivity and unsaturated hydraulic conductivity decreased and this reduction was more at low moistures. Sandy soil was affected less than loamy soil. In comparison of treatments that cause the least and the most dispersion, diffusivity and hydraulic conductivity for loamy soil, decreased 100% and for sandy soil at low moistures, diffusivity and hydraulic conductivity decreased about 91% and 99%, respectively.
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