Abstract

This paper describes an application of a contaminant transport model (OPUS) to simulate nitrate movement in the unsaturated zone of arable cultivated soil. The OPUS model was calibrated and validated using field experiments. The model reproduces the major trends of flow and transport phenomena and yields a suitable distribution of the water balance components as an output. It also adequately describes the movement of nitrate in the soil and represents closely field site measurements both in time and in space in such a manner as to predict levels of leaching within small margins of error (<1%). The model has an interesting potential, and is recommended as a practical tool for agricultural pollution research and evaluation.