Study of the flux of water and nitric nitrogen under roots on two catchment areas in the Val de Saône: experimentation with porous cups and modelling with AgriFlux

Abstract

Experiments were conducted on two catchment areas located in a flood plain in order to determine the nitrate concentrations under roots. A network of 15 agricultural sites representative of the diversity of soils and cropping systems was equipped with porous cups. This article aimed to give the main results obtained halfway through the study. The installation of the porous cups generated disturbances during the first monitoring period. The use of the AgriFlux model gave satisfactory results: simulated concentrations were similar to the measured values. The main factor determining the nitrate fluxes was the soil type: soil texture was a good criterion on which to assume the risks, which were more important in sandy than in clayey or loamy soils. Permanent grassland remained an effective filter protecting the groundwater. If rainfall played a driving part in the nitrate leaching, flooding seemed to have almost no influence.