The ecotron as a surrogate for reality. Too good to be true? (invited talk)

Finding solutions to adapt to the impact of global change is still one of the most important challenges of the 21st century. While huge modelling advances have been made and experimental methods to study the earth system are diversifying, a major problem to find those solutions remains: the unclosed gap between spatial and temporal scales. Results from controlled experiments in pots or greenhouses are sometimes difficult to relate to observations at the field and landscape scale due to the complex interplay of various processes. In addition, it has been hard to reproduce the future effects of climate change experimentally, leading to an inevitable extrapolation of model predictions to zones where no validation is possible.
Ecotrons provide unprecedented possibilities to study the soil-vegetation-microbiome-atmosphere continuum in highly controlled conditions and this under any climate scenario of interest. In this presentation, we will present the new Ecotron facility of the TERRA Research Center in Gembloux, Belgium designed to submit six mesocosms (small ecosystems) installed on lysimeters (2m² X 1,5m), to any climatic conditions desired and see how it can reproduce (or not) the current and future in-nature reality. In addition to the controlled variables, instrumentation is set up to monitor energy and water budget and ecosystem functions (yield and production quality, GHG mitigation and C storage, water retention capacity and leaching quality, soil fertility,…)
In the first experiment planned, we will compare the behavior of winter wheat plots submitted to present and future climatic conditions. The present conditions will mimic the situation already recorded on the Lonzee ICOS site. The future scenario will represent a typical year of the 2050-2070 period (drift of the mean annual value and increase of the temporal variabiity) and chosen for its ability to produce a contrasting crop yield.
The results will also give us information about the ability of ecotrons to reproduce a realistic ecosystem functionning and expose which aspects of plant growth and soil behavior are well and not well reproduced in the artificially generated climatic conditions. This phase is essential to demonstrate the actual potential and shortcomings of this cross-cutting research infrastructure