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Numerical analysis of the fate of nitrogen in the profile root zone of an agricultural field

Abstract:

The fate of nitrogen in the soil is of major concern because of the potential hazard that nitrogen, applied in excess of the natural decomposing capacity of the soil, contaminates shallow and deep aquifers. For the pbkp_rediction of the nitrogen behaviour in soils simulation models are frequently used. In this study the transport and fate of nitrate within the soil profile was analysed by comparing historic field data with the simulation results of two mathematical models, i.e. the WAVE and DRAINMOD model. Comparison between experimental measured and simulated state variables indicate that the nitrate concentrations in the soil is controlled by the fertiliser practice, the initial conditions and the rainfall depth and distribution. Furthermore, the study reveals that the models used give a fair description of the nitrogen dynamics in the profile root zone at field scale. From the comparative analysis between experimental data and simulation results it can also be concluded that both models after calibration are useful tools to optimise as a function of the combination 'climate-crop-soil-bottom boundary condition' the nitrogen application strategy resulting, from environmental point of view, in an acceptable level of nitrate leaching.