Simulation of nitrate movement in the subsoil profile of agricultural systems

Models are important tools in assessing the effect of agricultural practices on the quality of surface and ground waters. In this work, the model RZWQM (Root Zone Water Quality Model) is used in estimating nitrate concentration in the subsoil profile of an agricultural field cultivated with corn, under different fertilization and irrigation practices. The model was applied in a field near Kimmeria Village in Xanthi for year 2008. Meteorological data from the station of the Laboratory of Ecological Engineering and Technology, located in the area, were used. Three scenarios were evaluated with the model: the scenario of current condition, scenario 1 with double fertilization applied compared to the current condition, and scenario 2 where a different irrigation program was applied compared to scenario 1. In the top subsoil layer (depth 15cm), increased nitrate concentrations were predicted under scenario 2. In depths 60 cm, 90 cm, and 120 cm increased nitrate nitrogen concentrations 72 μg/g, 64 μg/g and 45 μg/g, respectively, were observed under scenario 1. RZWQM is a useful model for the estimation of impact of agricultural activities on ground water.