BIONUT GROUP :
Context of the research
The focus of the "Biogeochemistry of Nutrients" (BIONUT) team is on answering the question of how to sustainably manage nutrients (mainly nitrogen and phosphorus) to ensure agricultural and forest production while limiting environmental impacts. The team studies a variety of ecosystems ranging from field crops and cultivated grasslands to forests. The ecosystems studied are located in the Aquitaine region and throughout France. The team also has numerous collaborations on study sites around the world (Belgium, Brazil, Canada, Madagascar, New Zealand, Morocco, Siberia, Switzerland...).
The main objective of the BIONUT team is to improve our understanding of ecosystem functioning and biogeochemical cycles through:
- (i) the quantification of nutrient stocks and flows at different scales (plot, field, region, world)
- (ii) a mechanistic modelling of physico-chemical and biological processes.
Ultimately, it is about producing scientific knowledge, but also advice and good practices for managers of agricultural and forest ecosystems.
The team's three main themes are:
- The study and modelling of soil-plant relationships and soil functioning in response to nutrient bioavailability within terrestrial ecosystems. In particular, our team is studying the role of agricultural practices, biodiversity and climate change on the productivity and ecosystem services provided by terrestrial ecosystems.
- The study and modelling of the long-term functioning of biogeochemical cycles in terrestrial ecosystems. In particular, the team is studying how the coupling between nutrient and carbon cycles from small scales (microorganisms, roots) to much larger scales (regional, global).
- Modelling of phosphorus flows at encompassing scales. The team is studying here the determinants of phosphorus resource use and their impact on soil bioavailability on a global scale.
Approaches and Tools
One of the main characteristics of the team is to approach the biogeochemistry of nutrients from small to large scales by combining both experimentation and modelling.
The processes we are studying relate to soil functioning (transfer processes at the soil-solution interface, nutrient bioavailability, microbial and mycorrhizal communities), plant functioning (uptake of minerals by the root system, assimilation and allocation of carbon and mineral elements between organs, symbiotic nitrogen fixation) and the impact of management practices (agronomy and silviculture).
The main tools used are:
- Experimentation under controlled conditions on soil samples or plants grown in pots to assess nutrient bioavailability, soil functionning or uptake nutrients and growth of plants.
- In situ field experimentation to evaluate our models, identify species/forms of P (speciation) and quantify compartments and flows in the biogeochemical cycle.
- Mechanistic (or sometimes statistical) modelling as a conceptual framework to organize and formalize our research to produce numerical models. These are used for prediction, to develop and test scenarios, to quantify and prioritize the relative weight of modelled processes according to the contexts and scales considered, to produce or feed decision support tools.
- Analysis and use of statistical, bibliographical databases, to understand flows at inclusive scales, and to assess recycling opportunities.
Some important publications
Nadeem M, Mollier A, Morel C, Shahid M, Aslam M, Zia-ur-Rehman M, Wahid MA, Pellerin S. 2013. Maize seedling phosphorus nutrition: Allocation of remobilized seed phosphorus reserves and external phosphorus uptake to seedling roots and shoots during early growth stages. Plant and Soil 371: 327–338.
Gonzalez M, Augusto L, Gallet-Budynek A, Xue J, Yauschew-Raguenes N, Guyon D, Trichet P, Delerue F, Niollet S, Andreasson F, et al. 2013. Contribution of understory species to total ecosystem aboveground and belowground biomass in temperate Pinus pinaster Ait. forests. Forest Ecology and Management 289: 38–47.
Morel C, Ziadi N, Messiga A, Bélanger G, Denoroy P, Jeangros B, Jouany C, Fardeau J-C, Mollier A, Parent L-E, et al. 2014. Modeling of phosphorus dynamics in contrasting agroecosystems using long-term field experiments. Canadian Journal of Soil Science 94: 377–387.
Brédoire F, Bakker MR, Augusto L, Barsukov PA, Derrien D, Nikitich P, Rusalimova O, Zeller B, Achat DL. 2016. What is the P value of Siberian soils? Soil phosphorus status in south-western Siberia and comparison with a global data set. Biogeosciences 13: 2493–2509.
Regan JT, Marton S, Barrantes O, Ruane E, Hanegraaf M, Berland J, Korevaar H, Pellerin S, Nesme T. 2017. Does the recoupling of dairy and crop production via cooperation between farms generate environmental benefits? A case-study approach in Europe. European Journal of Agronomy 82, Part B: 342–356.