I have great pleasure in inviting you to my defense of my habilitation to supervise research at the University of Paris-Saclay on Monday 3 June 2024 at 2 pm in amphitheatre C2.0.37 (Building C2) at the Agro Paris Saclay Campus (22 place de l'Agronomie, Palaiseau, https://www.agroparistech.fr/venir-au-campus-agro-paris-saclay).

The presentation can also be followed by video via: https://inrae-fr.zoom.us/j/92581220587

I will present my work, dealing with « Characterizing and assessing ammonia volatilisation in the field in order to preserve air quality and optimise recycling and fertilisation »

The jury is composed of:

Dominique Courault, Research Director, INRAE, UMR EMMAH

Gaëlle Uzu, Research Director, IRD, IGE

Dominique Serça, University Professor, Université Paul Sabatier, LAERO

Valérie Gros, Research Director, CNRS, LSCE

Sylvain Pellerin, Research Director, INRAE, UMR ISPA - AgroEcoSystem Department

Benoît Gabrielle, Professor, AgroParisTech, UMR EcoSys

Abstract:

Reducing anthropogenic, and thus agricultural, ammonia emissions addresses several challenges: agronomic and therefore economic for the agricultural sector, on the one hand, and environmental, health and therefore also economic, but concerning the population as a whole, on the other hand. Ammonia volatilisation represents a significant loss of nitrogen for agriculture, and specifically for waste management and crop nutrition practices. Atmospheric ammonia also contributes to the degradation of air quality: after deposition, it is involved in acidification, eutrophication and the decline in biodiversity; it is also a precursor of fine particulate matters that are highly dangerous for human health.

My research activities aim at producing fundamental knowledge on ammonia volatilisation in the field, and cognitive and operational tools for their use in supporting research, technological eco-design, and public policy. They follow a trajectory that starts with the characterisation, understanding and modelling of a local and fugitive process, and goes all the way through to the evaluation of the associated agricultural practices in a context of increasingly prevalent context of climate change.

My work is based on the three pillars of acquiring experimental data, integrating knowledge into modelling and contributing to the acquisition of knowledge on this process. Measurement under actual farming conditions, in agronomic trial networks and under controlled laboratory conditions has required major metrological development, leading to the production of tools such as micrometeorological methods, wind tunnels and the Caract'Air disposal. These systems are used in a complementary way in order to acquire references on the effects on ammonia volatilisation of different categories of factors: agricultural practices including the fertiliser type, the application and/or abatement method, the plant cover status, as well as soil type and status, and meteorological conditions. I have also been deeply involved in mechanistic modelling: the Volt'Air model that I co-developed relies on the explicit representation of a set of processes. It takes into account the factors known to influence ammonia volatilisation on the spatial and temporal scales of a volatilisation event. Integrative of knowledge, it is well-suited for research. We use it as a complement to experimental observations to analyze them and provide interpretation keys. I also use more stochastic approaches: they enable us to propose more operational modelling with the view of interoperability with integrative tools, in particular agroecosystem models. To understand volatilization at larger scales, we have developed the Cadastre_NH₃ tool: it specifically combines Volt'Air with detailed, dynamic and georeferenced databases to calculate emissions related to the fertilisation of each crop in each small agricultural region at hourly time steps, covering the whole of France and of the crop year. Using this bottom-up inventory as a substitute for the top-down inventories of the national air quality forecasting platforms makes it possible to improve the calculations and target the practices to be promoted in terms of reducing background pollution and avoiding seasonal peaks in fine particulate matter pollution.

My scientific project continues and aims to be more ambitious, for two reasons. I would like to extend my contributions to the characterization of a coherent set of emissions into the environment: I plan to broaden them (i) to other nitrogen and carbon gaseous emissions, typically pollutants and greenhouse gases, and (ii) to cropping systems integrating other substrates, typically legumes and crop residues. At the same time, I would like to embed our evaluation work in a framework of more complex challenges by responding to a new perspective on questions concerning agricultural ammonia, particularly with a stronger focus on the emerging context of Global Health.

Looking forwards to seeing you!