Pierre Cellier

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The stomatal compensation point of ammonia (χs) is a major factor controlling the exchange of atmospheric ammonia (NH3) with vegetation. It is known to depend on the supply of nitrogen and to vary among plant species, but its seasonal variation has not yet been reported for grassland. In this study, we present the temporal variation of apoplastic NH4 +(More)
Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate–carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO2 exchange with the atmosphere(More)
Arable soils are a significant source of nitric oxide (NO), most of which is derived from nitrogen fertilizers. Accurate estimates of NO emissions from these soils are essential to devise strategies to mitigate the impact of agriculture on tropospheric ozone production and destruction. This paper presents the implementation of a soil NO emissions submodel(More)
Arable soils are a significant source of nitric oxide (NO), a precursor of tropospheric ozone, and thereby contribute to ozone pollution. However, their actual impact on ozone formation is strongly related to their spatial and temporal emission patterns, which warrant high-resolution estimates. Here, we combined an agro-ecosystem model and geo-referenced(More)
Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depended on improved methodologies, while ongoing challenges include(More)
A new study to address the biosphere-atmosphere exchange of ammonia (NH3) with grasslands is applying a European transect to interpret NH3 fluxes in relation to atmospheric conditions, grassland management and soil chemistry. Micrometeorological measurements using the aerodynamic gradient method (AGM) with continuous NH3 detectors are supported by bioassays(More)
Croplands mainly act as net sources of the greenhouse gases carbon dioxide (CO2) and nitrous oxide (N2O), as well as nitrogen oxide (NO), a precursor of troposheric ozone. We determined the carbon (C) and nitrogen (N) balance of a four-year crop rotation, including maize, wheat, barley and mustard, to provide a base for exploring mitigation options of net(More)