Role of Clay Minerals on Saturated Hydraulic Conductivity in Different Region of Iraq

Abstract

This study aims to found out the effect of exchangeable sodium percentage and salinity on saturated hydraulic conductivity, from the effect of swelling and dispersion process on aggregates of soil. Eleven pedons were selected for this study; two pedons were selected from Salah Al-Deen governate, while in Baghdad governate pedons were four, three pedons from Wasit governate and two pedons from Basra governate. Measured some chemical, physical and mineralogical properties on these samples were taken from the surface and subsurface horizons of each pedon. The results showed that the clay has effect on physiochemical process, especially with high content of ESP, which effecting negative in soil properties (bulk density and saturated hydraulic conductivity). Whereas, the highest value of bulk density (1.47 – 1.66 Mg.m-3) which caused decreased in Ksat (1.22-2.03 cm.h-1) for P3, P4, P5, P7, P11, P8C1, P10C1, where showed high interaction between ESP and clay in case montmorillonite domance. The domance of chlorite mineral in P8AP, P9AP, P9C1 caused to increase Ksat value (4.02–5.90 cm.h-1) while the bulk density was decreased (1.33–1.38 Mg.m-3). Decreasing of ESP (9.19-12.04 %) and domance of chlorite and mica mineral in P6C1, P10AP, caused to increase Ksat value (8.17-10.90 cm.h-1).