Modeling the spatial evolution of nitrogen pollution in groundwater and the amount of nitrogen leached under potato crops in the Khemis Miliana Plain

The maximum concentration of nitrates in drinking water admitted by the World Health Organization is 50 mg nitrate per liter of water. Europe recommends a standard content of 25 mg NO3- / l according to the interdisciplinary research program on the environment (2009). The present work quantifies spatially the evolution of this pollution and determines and estimates the influence of agricultural practices "calendars of irrigation and fertilization" on the quantity of nitrates leached under the potato crops towards the groundwater of the Khemis-Miliana plain using a new model Pilote N. The spatial evolution of the average nitrate concentrations above the norms in the groundwater of the Khemis-Miliana plain represents 80% of the total area of the plain. The transfer of nitrates through the unsaturated zone was simulated by the PiloteN model giving an estimate of the amount of N leached under the potato crops, which represents, according to the model, 50% of the total nitrogen supplied (300 KgN / ha) on the ground. According to the model, the nitrogen leaching period is greater and coincides with the days of fertigation. In this context, a field study was conducted to get an idea of these agricultural practices (time, doses of fertigation ...) brought to the soil of the Khemis-Miliana plain in order to know, on average, the quantities of nitrogen leached by calculating the nitrogen balance at the potato plot scale using an empirical method and the PiloteN model.