Biochar: a climate smart tool for agricultural soils?
Soils play a crucial role in adaptation and mitigation to climate change that originates from anthropogenic greenhouse gas emissions (GHG). The agricultural sector, which corresponds to about 11% of the GHG emissions in both Belgium and the world (2016), has the potential to reduce its emissions through carbon storage in soils and increasing biomass productions.
The CHAR project, conducted at the University of Liege, investigates soil management practices that allow for the decrease in GHG emissions and for the improvement of crop performance while decreasing fertilizer inputs. This project studies the effects of charcoal accumulation (a carbon rich solid phase produced by pyrolysis) in the soil on the carbon storage, nutrient and water cycles and agronomical performance.
During the 18thcentury in Wallonia, the production of charcoal was greatly developed in order to provide energy for pre-industrial steel industry. During this period, 75% of the deforested land in Wallonia was dedicated to the production of charcoal, resulting in numerous black patches (called aires de faulde) still visible today in agricultural field. This charcoal enrichment (biochar) leads to modifications in biogeochemical and hydrodynamic properties of Walloon soils.
Many studies have shown that biochar increases fertility and water holding capacity in soil in addition to increase carbon stocks. However, most of the research has been carried out in tropical and equatorial contexts during short-term experiments. In order to consider biochar as a sustainable and efficient agro-technology, it is necessary to better understand its long-term effects on the soil-plant system. This interdisciplinary project focuses on agronomical and environmental effects of century-old biochar amendment to define the efficiency and sustainability of this agro-technology.
This project, characterized by an interdisciplinary and multi-scale approach, has implemented an observatory based on a fully instrumented experimental set-up. This observatory is unique in Europe due to its implementation in a currently cultivated field (farm managed by Alexandre Godfrind) and its high frequency monitoring of physical and chemical variables within black patches, enriched in century-old biochar. This interfaculty ARC-ULiège project is based on the work of 2 PhD students (Ramin Heidarian Dehkordi and Victor Burgeon) and a postdoctoral fellow (Julien Fouché), and gathers three research environments from the groups « Echanges Eau-Sol-Plante » from Gembloux Agro-Bio Tech (Prs. S. Garré et J-T Cornelis ; biogeochemical processes affecting water, carbon and nutrient cycles), "Urban and Environmental Engineering" for the faculty of Applied Sciences (Pr. F. Nguyen ; spatialization of the hydrodynamic behaviour using geophysic imaging techniques) and "Eau Environnement Développement" from the faculty of sciences in Arlon campus (Pr. B. Tychon ; crop yield monitoring using remote-sensing). This holistic approach built on an outstanding field site will highlight the agro-ecosystem responses to biochar enrichment at different spatial and temporal scales (from micrometrical soil pores to the field crop scale).
