Nitrogen fertilization management in agriculture: Environmental issues and agronomical prospects for the French territory

Nitrogen bioavailability remains one of the main factors regulating plant production in agriculture. During the last 30 years the use of nitrogen fertilizers has stabilized in France in parallel with a substantial increase in the production of the main plants, indicating better efficiency of these fertilizers. However, during this same period water contamination by nitrogenous compounds has risen sharply. Despite the identification of signs of stabilization or improvement over the last decade, water pollution by nitrates remains highly worrisome. Limiting nitrogen inputs to the sole needs of vegetation seems a mode of reasoning capable of containing this pollution. Applying the mineral nitrogen balance-sheet method as a general tool for predicting nitrogen fertilization requires further calibrations according to local contexts. In parallel to its generalized application it is necessary to continue research on production methods allowing a reduction of nitrogen losses from agricultural ecosystems.