TADA, a mechanistic model for carbon, nitrogen and water cycles in cropland and grassland ecosystems

It has been several years since Gembloux Agro-Bio Tech manages two eddy covariance sites, one located on a pasture at Dorinne and the other on a 4-year crop rotation at Lonzée. A large dataset is therefore available to run a model able to help us understanding the temporal variability of the greenhouse gases exchanges. In this regard, three master theses aimed to develop an ecosystem model which can simulate the carbon, nitrogen and water cycles of a grassland and a cropland. This model, named TADA (Terrestrial Agroecosystems Dynamics Analysis), is based on the mechanistic 1D model ASPECTS developed for forests and was adapted by including specific phenology, allocation scheme, management and grazing modules proposed in the litterature. During these Msc theses, some processes simulated in TADA (such as photosynthesis, soil evaporation, nitrification, etc.) were calibrated against data obtained on the experimental sites (on winter wheat crop and grazed grassland). We will present the model and highlight the improvements that could be made to improve the processes description as well as the measurements needed for a better calibration of these processes, as this is a long-term project.