Shainberg, I., Inst. of Soils & Water, ARO, The Volcani Center, Bet Dagan, Israel.
Singer, M.J., Inst. of Soils & Water, ARO, The Volcani Center, Bet Dagan, Israel.

Depositional crusts form when turbid water infiltrates into soils. These crusts may reduce water infiltration rates. The effect of four concentrations of fine particles (0, c 0.25, c 0.5, and c 1.0%) and two electrolyte concentrations (0.001 M and 0.005 M Cl -) on water infiltration rate was studied. Infiltration and hydraulic conductivity (HC) of two nonsodic soils were not affected by leaching with the salt solutions because the electrolyte concentration in the percolating water was sufficient to prevent clay dispersion and swelling in the soils. The clay and silt that deposited at the soil surface decreased the water infiltration rate. The HC of the depositional crust was 2 and 3 orders of magnitude less than the HC of bulk soils in the 0.005 M solutions, respectively. The rate of crust formation and the decrease in infiltration rate increased with increase in the solids concentration. Applying a -1.5-kPa potential reduced crust HC but had no effect on soil HC. The effect of a potential was more pronounced on the crust deposited from the 0.005 M suspensions than on crust deposited from 0.001 M suspensions. -Authors