A 1:50,000 scale soil map for the Saclay plateau

Project team: Joël Michelin, Ophélie Sauzet, Ottone Scammacca, Olivier Fontenas and David Montagne (ECOSYS)

The health and well-being of human populations depend on the multiple services provided by nature. In continental environments, soils contribute directly or regulate the levels of provision of many services (production of biomass, drinking water, regulation of global and local climates, regulation of water quality, etc.). Even though soils are receiving more and more attention, they remain particularly poorly understood, especially at the territorial level, where a need for knowledge is being expressed more and more frequently by local authorities, farmers and the general public.

The objective of the 1:50,000 soil mapping project is to characterize, synthesize in the form of a digital map and finally share the diversity, spatial distribution and condition of soils on the Saclay plateau. The project was coordinated and implemented by the Soil Science team of the ECOSYS joint research unit. It benefited from the results acquired during preliminary work, including the project for the creation of a pedological trail supported by La Diagonale Paris-Saclay in collaboration between the UMR Université Paris-Saclay/CNRS GEOPS, the UMR Université Paris-Saclay/INRAE/ AgroParisTech ECOSYS and the association Terre et Cité.

The soil mapping project synthesizes, in digital form, fundamental knowledge about soils that can be used by a wide range of stakeholders, including land-use planners, farmers, natural resource managers (water, biodiversity, etc.) and educational and research stakeholders.

The soils of 3,400 hectares of natural agricultural or forest areas have been mapped, i.e. 82% of the Natural, Agricultural and Forest Protection Zone (ZPNAF) of the Saclay plateau. On this surface, 15 soil mapping units have been identified for a total of 33 soil typological units. The 33 soil typological units are characterized by a representative soil profile that has been systematically described and, for the most abundant units, by analytical characterizations of their main physico-chemical properties (texture, pH, Cationic Exchange Capacity (CEC), organic carbon, nitrogen, phosphorus and limestone concentrations, etc.).

The project leader explains the project and its RESULTS in VIDEO (LabEx BASC scientific days, December 2020)

The knowledge acquired on the soil resource of the Saclay plateau has already been (re)mobilized in i) various research projects including the ASSETS and DRAIN-ACT projects supported by LabEx BASC; ii) numerous training courses, in particular the Master 2 course in Soil Management and Ecosystem Services (GSSE) at the University of Paris-Saclay and the AgroParisTech engineering course; and finally iii) the territorial development of the plateau (experimental agricultural device on the edge of the Corbeville ZAC, Marnières site, etc.).

As a representation of one of the essential components of the natural capital, the 1:50,000 map of the soils of the Saclay plateau could constitute the basis of a future observatory of the local environment of the Saclay plateau, the objective of which would be to centralize environmental information for bio-monitoring or for the management, elaboration and monitoring of public policies. In this perspective, the first characterizations of soil biodiversity (microorganisms, earthworms) were launched in 2019.

Publications

> Choquet P., Gabrielle B., Chalhoub M., Michelin J., Sauzet O., Garnier P., Baveye P.C. and Montagne D., 2021. Comparison of empirical and process-based modelling to quantify soil supported Ecosysem Services on the saclay Plateau (France). Ecosystem Services. Accepted.