Fluxes and forcing in the Critical Zone "F2ZC" Team - iEES Paris

The research is conducted in landscapes subject to particularly intense land use changes, with two major objectives:

on the one hand, the characterization of the biophysical processes of soil structuring, that is to say the characterization of the physical and biological mechanisms of soil aggregation and disaggregation, on which many soil properties depend (storage and transfer of Water and solutes, in particular); it is a question of understanding the spatial and temporal variations of these processes within landscapes subject to changes in use.
On the other hand, the evaluation of the effects of changes in biophysical processes on the provision by the soil of ecosystem services: primary production and climate regulation services by carbon sequestration, regulation of floods and erosion under its different shapes; it is a question of assessing the repercussions at the level of the plot, the catchment area, or the terroir, of changes in the nature or intensity of local biophysical processes.

This project is declined in three complementary axes:

The first axis analyzes the landscape and soil dynamics resulting from changes in use.

It relies on long-term observatories, such as the watersheds of the MSEC (MultiScale Environmental Changes) system to:

Identify the determinants of changes in use;

• Evaluate the effects of agricultural practices on:
• The diversity of plant cover, its fragmentation;
• Plant biodiversity and soil fauna;
• The surface conditions of the soil, in the different elements of the plant mosaic, which influence the partition of rainwater between infiltration and runoff.
• The second axis is central to the project, as it aims to understand the links between changes in land use and their impacts on soil functioning. Through field and laboratory experiments, it is a question of analyzing the influence of biotic and abiotic factors and their interactions on the hydro-structural properties of the soil, using the tools of the Alysés platform. at Bondy, in particular the retractometer, geophysical and isotopic measurement devices.

The third axis assesses the impacts of changes in use on flows; in other words, it seeks to integrate local biophysical processes into the functioning of soil-plant, soil-atmosphere and watershed systems. He is particularly interested in the hydric functioning of the soil and in the productivity of tree crops, in relation to the development of root systems, using geophysical tools.
The study of the growth of fine roots in depth is continued because of their contribution to the water supply of plants.
We are also trying to model water flows and particle emissions to the atmosphere and hydrographic networks as a function of the evolution of the hydro-structural properties of soils.
Finally, we assess the health risks resulting from changes in use in Asia, by monitoring the bacterial quality of soil and water.

The Forcing and Flow in the Critical Zone (F2ZC) team is made up of 10 researchers, 2 of whom are posted in Africa, and 6 IRD engineers and technicians, attached to the IRD Center Fle-de-France delegation. in Bondy (93) including 3 affected in Africa or Asia.