Modelling the fate of nitrogen following pig slurry application on a tropical cropped acid soil on the island of Réunion (France)

A comprehensive field study was conducted to determine the fate of nitrogen in pig (Sus scrofa) slurry applied to an acid tropical andic soil of Réunion with the aim of estimating drainage and nitrogen leaching below the root zone. Water movement and nitrate dynamics were monitored during two successive cropping seasons on a plot (PSP) treated with liquid manure, with an input of 264 kg N ha−1 the first year and 185 kg N ha−1 the second year, in comparison to levels recorded in a unfertilized control plot (CP). The field was cropped with rainfed maize (Zea mays L.) The process-based WAVE field-scale model was used to simulate water flow and nitrogen transport in the unsaturated zone and highlight the main processes controlling water and N fate. A calibration procedure was performed one year, while the prediction capability of the model was assessed during another cropping year. A sensitivity analysis was performed to address some critical parameters.