Development of the OC_VGEN model: simulation of soil carbon dynamics

Scientific leaders: Sophie Cornu <sophie.cornu@inrae.fr> (INRAE, UMR CEREGE, Aix-en-Provence) and Hamza Chaif <hamza.chaif@inrae.fr> (INRAE, UMR CEREGE, Aix-en-Provence).

The OC_VGEN model has been developed in the VSoil platform to simulate soil carbon dynamics over time.

Details of the work carried out under this theme are presented below.

• Saba Keyvanshokouhi (PhD student from 2014 to 2017)

Saba Keyvanshokouhi (Ghent University, Aix-Marseille University) developed the OC_VGEN model during her PhD. This model uses modules for the transfer of water, heat, solutes, gases and colloids in the soil that are already available in VSoil, some of which have been very slightly adapted to the problem. Several modules have been developed: carbon dynamics in the soil (inspired by RothC) and for mulch, geochemistry, solute extraction, chemical or physical alteration of minerals, two approaches to bioturbation and tillage. The evolution of density as a function of organic carbon content was implemented in a module with feedback on various mechanisms. An evolution of VSoil has been to implement an adaptive mesh to take account of compartments that become too thick or too dense over time. This model still needs to be adapted to achieve its objectives of predicting changes in soil characteristics over time, but it has already produced published results on changes in carbon profiles.

Reference article:

Saba Keyvanshokouhi, Sophie Cornu, Lafolie, F., Balesdent, J., Guenet, B., Moitrier, N., Moitrier, N., Nouguier, C., Finke, P. Effects of soil process formalisms and forcing factors on simulated organic carbon depth-distributions in soils. Science of The Total Environment, 2019, 652, pp.523-537. https://doi.org/10.1016/j.scitotenv.2018.10.236, https://hal.inrae.fr/hal-01904523v1