The French National Research Institute for Agriculture, Food, and the Environment (INRAE) is a public research establishment under the dual authority of the Ministry of Agriculture and the Ministry of Research.
It is a major player in research and innovation created on 1st of January 2020. INRAE is a research institute resulting from the merger of INRA and IRSTEA. It is a community of 12,000 people with more than 200 research units and 42 experimental units located throughout France.
The institute is among the world leaders in agricultural and food sciences, in plant and animal sciences, and is 11th in the world in ecology and environment. INRAE’s main goal is to be a key player in the transitions necessary to address major global challenges. In the face of the increase in population, climate change, scarcity of resources and decline in biodiversity, the institute develops solutions for multiperformance agriculture, high quality food and sustainable management of resources and ecosystems.
You will join the ECOSYS (Functional ecology and ecotoxicology of agroecosystems) Joint Research Unit, which studies the integrated functioning of agroecosystems and associated ecosystem services. You will be at the interface of two structuring themes of this Unit ("valorisation of organic residues" and "climate change") and will work for the Soil team. You will find skills in biogeochemistry of organic matter, microbial ecology and modelling in this team. You will benefit from the unit's environmental analytical platform for using stable isotopes, facilities for conducting experiments under controlled conditions, long-term field experimental facilities managed by the unit. Beyond the unit, you will work closely with specialists in the upstream treatment of organic residues (INRAE Narbonne and Rennes) and also researchers from ENS Ulm developing approaches for the energetic characterization of organic materials.
Soil organic matter is the source of many ecosystem services, such as carbon storage in soils and the provision of nutrients to plants. With the evolution of cropping systems and the diversification of biomass recovery techniques, organic inputs in soils are more diversified, ranging from unprocessed plant biomass (crop residues, intermediate crops) to highly transformed materials upstream (composts, digestates, biochars, etc.). This raises the question of whether upstream transformations of organic residues modify the processes and dynamics of their incorporation and stabilization in soils. In this context, it is necessary to (i) assess the relationship between the characteristics of the organic inputs, microbial biomass assimilation yields and incorporation into soil organic matter; (ii) estimate the consequences on their fate in the short-, medium- and long-term, including mineralization and nitrogen emission flows; and (iii) determine the best compromise between the degree of upstream transformation and the associated services after addition to soils. “Model chains" of more or less transformed organic residues for soil application will be made from 13C and 15N labelled material (crop residues, faeces, compost, digestates of methanisation, biochars obtained by pyrolysis). You will study their incorporation into fractions of soil organic matter indicative of kinetic compartments, their soil microbial biomass assimilation yields and their mineralization kinetics by linking them to the characteristics of the materials supplied (chemical nature, degree of stability and energy characteristics). You will carry out quantitative assessments of carbon and nitrogen throughout the chains studied including gaseous emissions. The processes identified using these "model chains" will then be quantified in "real chains" of transformation and contribution within long-term experimental sites.
You have a PhD or equivalent, ideally with proven experience in organic or isotopic biogeochemistry and knowledge of soil sciences.
Candidates should have a good command of English, and long-term international experience would also be desirable. Successful candidates who have not yet acquired this experience abroad will be required to do so after their probationary period (1st year).