Herbicide Soil Leaching & Groundwater Breakthrough

Herbicide pollution rarely stays where it's sprayed. This simulator models a real solute-transport process: a pulse of herbicide applied at the soil surface advects downward with infiltrating rainwater while continuously partitioning between dissolved and soil-bound phases, exactly as described by the linear equilibrium sorption model used in hydrogeology. Switch between four real herbicides spanning three orders of magnitude in soil affinity (dicamba, 2,4-D, atrazine, glyphosate), tune organic-carbon content and rainfall, and watch the retardation factor decide whether the plume reaches the water table in weeks or effectively never leaves the topsoil.