Observation des concentrations et flux d’azote atmosphériques dans le bassin versant de Kervidy-Naizin Une contribution au projet Européen ‘NitroEurope’ Christophe Fléchard, Yannick Hamon, Yannick Fauvel, Patrick Durand INRA / UMR SAS http://www.nitroeurope.eu/

NitroEurope (NEU): 65 instituts ou universités, ~20 pays (2006-2010)

NitroEurope objectives: To establish robust datasets of N fluxes and net greenhouse-gas exchange (NGE) in relation to C-N cycling of representative European ecosystems, as a basis to investigate interactions and assess long-term change, To quantify the effects of past and present global changes (climate, atmospheric composition, land-use/land-management) on CN cycling and NGE, To simulate the observed fluxes of N and NGE, their interactions and responses to global change/land-management decisions, through refinement of plot-scale models, To quantify multiple N and C fluxes for contrasting European landscapes, including interactions between farm-scale management, atmospheric and water dispersion, and consideration of the implications for net fluxes and strategies, To scale up Nr and NGE fluxes for terrestrial ecosystems to regional and European levels, considering spatial variability and allowing assessment of past, present and future changes, To assess uncertainties in the European model results and use these together with independent measurement/inverse modelling approaches for verification of European N2O and CH4 inventories and refinement of IPCC approaches. These objectives are met by a programme that integrates: an observing system for N fluxes and pools [Component 1] a network of manipulation experiments [Component 2] plot-scale C-N modelling [Component 3] landscape analysis [Component 4] European up-scaling [Component 5] and uncertainty and verification of European estimates [Component 6].

C1 C2

C3 C4

C5 C6

Kervidy-Naizin: 1 site ‘Paysage’ parmi 6 dans NEU-C4 (Bretagne, Danemark, Ecosse, Italie, Pays-Bas, Pologne) Modélisation intégrée des transferts d’azote à l’échelle du paysage, dans les 3 volets: agronomique hydrologique atmosphérique Dispositif atmosphérique: Réseau de 30 capteurs NH3 ‘ALPHA’(concentrations mensuelles) Suivi mensuel des flux NH3 végétation/atmosphère: 2 sites (prairie et céréale) Suivi mensuel des émissions de N2O: 4 sites (prairie, zone humide, culture de printemps, céréale d’hiver), 5 répliques par site. En collaboration avec l’UMR INRA/AgroParisTech EGC de Grignon Période 2007-2009

Dispositif atmosphérique Kervidy-Naizin

Badges ALPHA – concentration mensuelle en NH3 atmosphérique

Concentration en NH3 (mg m-3) modélisée par LADD

Trains d’échantillonnage DELTA – concentration mensuelle en NH3, HNO3, SO2, HCl, aerosol NH4+, NO3-, Ca2+, Mg2+, Na+, Cl- Air

Flux d’NH3 végétation/atmosphère Mesure par système TAG (‘time-averaged gradient’)

Flux de N2O par chambres statiques