Coupling easily numerical models using the VSoil modelling platform

Located at the interface between the groundwater table and the atmosphere, soil lies at the core of the critical zone. It is a complex, dynamic environment sustaining essential ecosystemic services and biodiversity. Numerical simulation models of soil processes are invaluable tools for tackling the complex issues involved in understanding and predicting physical, chemical and biological cycles, in relation to agricultural production, soil protection and adaptation to climate change. To provide a detailed representation of soil functioning, it is necessary to couple a large number of models that represent the various processes taking place within it. Modelling platforms help to do this by facilitating the development and use of coupled models of soil processes. A key requirement of such platforms is to be able to integrate existing, already validated, models without major difficulties.

To this aim, we present the VSoil modelling software platform (https://vsoil.hub.inrae.fr/) developed at INRAE (France’s National Research Institute for Agriculture, Food and Environment) since 2009 in close collaboration between scientists and software engineers. VSoil is an open-source platform designed to aid the development of numerical models at the soil profile scale describing physical, chemical and biological processes in soil and its interactions with climate and plants but also anthropic activities. The user-friendly workflow of VSoil simplifies the development and use of models, making them accessible even to scientists with limited experience in computer programming. The VSoil software suite comes with a range of already developed models and is designed to guide users as much as possible in addressing their scientific questions, by providing tools for: i) defining and describing pertinent soil processes and their interactions through their input and output variables, ii) developing elementary models, called modules, which are numerical representations of the processes, iii) assembling and coupling these modules into more or less complex models, and iv) parametrising and executing the resulting models, and visualising results. The VSoil team provides user support and regularly adds new features to meet the needs of the user community. VSoil currently offers key features, including: i) model exploration tools (sensitivity analysis and parameter estimation) along with the ability to run models on several sets of input data, ii) the possibility to run models, in a reproducible way, on a remote computing environment (server or cluster), iii) the connection to INRAE's national agroclimatic database. VSoil fosters collaboration between scientists from various disciplines and facilitates the sharing and use of new developments within the platform's user community.

VSoil is being used by scientists from various countries to address very diverse questions such as the fate of persistent fluorinated pollutants in soils, the impact of treated wastewater on soil, the use of geophysics for non-destructive characterisation of soil hydraulic properties, the fate of pesticides at the landscape level, the simulation of soil carbon dynamics, or the optimisation of forestry machinery operations to mitigate soil degradation and compaction.