CATCHMENT AGRONOMY: PROCESSES, MITIGATION MEASURES AND INDICATORS TO PROTECT WATER QUALITY

While many scientific studies show the influence of agricultural landscape patterns on the water cycle and water quality, only few of these have proposed scientifically-based and operational methods to improve water management. Territ'eau' is a framework developed to adapt agricultural landscapes to water quality protection, using components such as farmers' fields, semi-natural areas or human infrastructures. The nitrogen (N) module is presented here. This enables the estimation of nitrate fate scores: i) at plot level, integrating them on the length of the crop rotation, taking into account environmental drivers (soil, climate) easily available by regional data sets; ii) at catchment level, identifying and qualifying functional semi-natural areas in terms of denitrification and dilution, and assessing their limits and functions, finally calculating nitrate fate scores per headwater catchment. This N module is integrated in a holistic method which allows us to objectivise the functions of the landscape components, and constitutes an established approach for adapting them to new environmental constraints. This framework helps in proposing different approaches for changing agricultural landscape, acting on agricultural practices or systems, and/or conserving or re-building semi-natural areas in controversial landscapes.