| Irrigation of arid and semi-arid agricultural regions has produced waterlogging and salinization problems. This research investigates the simulation of how management alternatives control drainage quantity and quality and demonstrates an improvement over the use of the conceptual models, leaching fraction and leaching requirement.;HYDRUS_2D, a two-dimensional Windows-based modeling environment, is used here to simulate solute transport under the influence of alternative irrigation management practices for an alfalfa crop. HYDRUS_2D uses a finite element technique that numerically solves the Richards equation for saturated and unsaturated flow, and the Fickian-based advection/dispersion equation for solute transport in variably saturated porous media. The response to management alternatives (depth of irrigations, using water sources of varying quality in irrigating a soil with varying salinity) allows managers to evaluate the influences on the mass flux of salts in drainage water and concentrations in the soil profile before they put a new approach into practice. |
