Know more

Context and issues

The recycling of exogenous organic matter (EOM) in agriculture, in raw form or after treatment, is strongly encouraged by the European Union in the framework of a circular economy. Indeed, these EOMs present amending and/or fertilizing properties and can therefore improve the physical, chemical and biological properties of soils, with moderate implementation costs. However, these EOMs can also be a source of contaminants, impact the quality of crops, water (leaching of NO ^-) or air (GHG emissions, NH ). All these effects are simultaneous and need to be evaluated over the long term with repeated applications in order to provide decisive information on the sustainability of the sector.

To evaluate the practice as a whole, we developed a multi-criteria method (Obriot et al., 2016) based on results acquired from a field trial (QualiAgro) in which different types of EOM are applied every 2 years at a rate of 4t C/ha, and 15 years after its implementation. More specifically, we developed and calculated 7 soil quality indices (biodiversity, biological activities, physical properties, soil fertility, C storage, "total" health status, "available" health status) and a crop quality index. These indices were constructed from parameters selected by experts and statistical methods. This approach made it possible to assess the effects of repeated applications of EOMs by targeting different functions that reflect different ecosystem services or disservices and to differentiate between EOMs. The different qualities of these EOMs led to different responses for each impact category, which can be used to develop an approach for selecting EOMs to be used according to an objective of improving a component of soil and/or crop quality.

Although this tool gives interesting results, it was built from a large initial number of parameters obtained on a long-term trial dedicated to research and which will be difficult for farmers to acquire on a routine basis (time-consuming analyses, too high costs). A first phase of work therefore aims to test the effects of the number and type of indicators in the different indices on the final results.

This tool also needs to be tested on other long-term trials dedicated to the study of the impacts of repeated applications of EOMs on soil and crop quality. It could be tested on other French and European sites, which have been identified by Belgian colleagues within the EOM4Soil project, in order to diversify the pedoclimatic contexts and the type of EOMs.

Depending on the data available on the different sites, this tool could be further completed and improved by taking into account other relevant indicators and/or indices.

Tasks of the post-doctoral fellow

1. Test the reduction of the number of indicators by selecting in a random or targeted way a limited number of indicators within each index category and by studying the impact on the results
2. Test the tool in other soil and climatic contexts and with other EOMs after a first phase of analysis of existing long-term European trials and data available on these different sites (in collaboration with other project actors and site managers)
3. Enrich the tool by considering other indicators in the existing indices (e.g. GHG emissions to assess the climate regulation service, microplastics in contaminants…) and/or by developing other indices

The mission will also consist in valorising the work in the form of scientific article(s).

Work context

This post-doctorate is part of the EJP Soil EOM4Soil project and more particularly of WP3. It will be carried out at the INRAE-AgroParisTech ECOSYS UMR "Functional ecology and ecotoxicology of agroecosystems" (https://www6.versailles-grignon.inrae.fr/ecosys) located in Palaiseau (91, France). This unit hosts approximately 110 permanent agents, including about 50 researchers and teacher-researchers. The UMR's work aims to address the functioning of agroecosystems and their relations with the environment. ECOSYS is organised into two scientific divisions: Soil Science-Ecotoxicology and Ecophysiology-Physicochemistry of Vegetation-Atmosphere Interactions. The skills and scientific and technical approaches of the different teams are mobilised and pooled to work on transversal themes corresponding to the different ecosystem services provided by agroecosystems. These structuring themes are i) Management, production and recycling of biomass, ii) Climate change and agroecosystems: mitigation and adaptation, iii) Exposure and effects of contaminants in agroecosystems, iv) Diversity from plot to landscape for a resilient agroecosystem with limited impact. 

Work conditions

The person recruited will work with L. Vieublé Gonod and S. Houot (UMR ECOSYS) and A. Michaud (UMR INRAE-Institut Agro "Sol, Agro et hydrosystèmes, Spatialisation" of Rennes) who are involved in the EOM4Soil project. The position will be based at ECOSYS 22, Place de l'Agronomie 91120 Palaiseau.

The contract (full time) will last 12 months and will start in April-May 2023. The salary will be approximately €2700 per month.

Candidate profile

Minimum level: PhD (with or without post thesis experience)

Technical and scientific skills: agronomy, soil science and/or environment Computer skills: Office pack, R, statistics and data analysis.

Language skills: English (fluent)

Other skills: scientific curiosity, dynamism, rigour, autonomy, capacity for analysis and synthesis

Application

Send CV and cover letter to Laure Vieublé Gonod (laure.vieuble@inrae.fr), Sabine Houot (sabine.houot@inrae.fr) and Aurélia Michaud (aurelia.michaud@inrae.fr) before 10/03/2023, to take up the position in April-May 2023.