Impacts of Intensive Irrigation on Low Conductivity Soils Near Coastal Areas: Experiments and Modeling

In this work we present the experimental and modeling approach using steady-state centrifugation for the study of contaminant transport of nutrients derived from agriculture related activities.  The extensive use of inorganic fertilizers can lead to serious environmental and health hazards.  The research focuses on the understanding of the impacts of nitrate and phosphate nutrients derived from fertilizers when applied to semi-arid regions of soils with low hydraulic conductivity under unsaturated conditions.  The experimental setup uses a steady-state centrifugation (SSC) Unsaturated Flow Apparatus (UFA), where centrifugation force is used to shorten the time required for nutrients to migrate in a low permeability soil, such as clay, and to control saturation level.  This study further aims to extend the application of current computer models, which simulate contaminant transport in unsaturated soils, to include centrifugation effects and centrifugation derived hydraulic characteristics.  The results of the extended application of the model are compared against the data from this experiment.