Effect of clay dispersion on infiltration into bare soils: Multi-stage infiltration equations

A correct description of the infiltration process into soil is important in hydrologic and soil erosion studies. Often, rainfall simulators are used to obtain measurements of infiltration. The objective of this paper is to report results of infiltration measurements from laboratory experiments making use of a rainfall simulator and a soil flume and to present infiltration equations that can account for breaks in infiltration rate. The soil material used was from a saline and sodic regolith profile developed on marine marls in a badland area of S.E. Spain. Breaks in infiltration rate can occur due to, for example, solute release and transfer into overland flow, or changes in soil texture and structure. The simplified, empirical, multi-stage infiltration equations proposed in this study, based on the Horton equation, were fitted to the experimental data. These equations describe adequately infiltration under the referred laboratory conditions.