The processes upon which we focus concern the exchanges between a plant and its environment (atmosphere, soil) as well as the internal functioning of the plant and the culture-pathogenic complex. The applied concepts and approaches include plant ecophysiology, pathology and biophysics of the environment. We focus more specifically on the mechanisms involved (i) in the use of environmental resources by crops, particularly nitrogen (in different mineral or organic forms) and water, and (ii) in the response of crops to constraints (ozone, diseases). This work is conducted from the perspective of low-input production (fertilization, crop protection) and peri-urban agriculture in particular.

The contribution of ECOSYS involves the development of agroecosystem response functions, based on experimentation under controlled or natural conditions and modeling. The experiments encompass different time scales, ranging from a single episode (deficiency or emergence of nitrogen deficiency, parasite attack, ozone peaks) to the medium or long term (rotation, considering climatic variability). Regarding modeling, the work ranges from the fine process scale (ozone detoxification, host-pathogen interactions, nitrogen uptake, pathogen dispersion) to integrative approaches at the canopy level.

The objectives of this axis were as follows:

• Strengthen work on vegetation cover–atmosphere-soil interactions in agroecosystems, particularly by developing the root component.
• Continue the integration of knowledge into integrative models at the plant cover organization level (CERES- EGC, STICS, FSPM).
• Further extend the introduction of the diversity-heterogeneity factor into work on plant resilience to stress (nitrogen, water, pests).
• Strengthen the consideration of spatial and economic dimensions in considering the impacts of these constraints on production.

The highlights achievements were as follows:

➢          The actions carried out within the contractual projects BREEDWHEAT (2011-2019) and RAPSODYN (2012-2020), WHEATAMIX (2014-2018), Accaf-CLIF (2013-2017), various projects based on the QualiAgro Observatory (SOERE- PRO) and on ICOS (ECLAIRE).

➢          Consolidation of collaborations within LabEx BASC addressing genetic aspects in the design of wheat variety associations (Plant Genetics Unit of Moulon), integration into new cropping systems (Grignon Agronomy unit) and the dynamics of pathogenic fungi (BIOGER unit).

➢          Internal reflection within the unit regarding the soil-root interfaces and the place of roots in the unit’s project, which resulted in the proposal of a scientist profile and recruitment of a CR (Frédéric Rees) in 2017.

This axis is mainly driven by the Eco&Phy team (addressing topics related to plant ecophysiology and pest dynamics), under which 64% of publications (97 peer-reviewed articles) can be related to the theme of the axis. The transversality of the axis within the unit is demonstrated by the co-signature of 14 articles between at least two different teams. All the publications (and most of the projects) attached to this axis are also related to other axes, showing the interactions between the outputs defining the axes and providing evidence of the need to take into account the trade- offs between services.