Contribution of soil organic carbon variations to the life cycle analysis of a farm: case study in Belgium and methodological recommendations

Abstract

Agricultural systems are facing numerous environmental challenges. Increasing soil organic carbon (SOC) content has been suggested as a means to both mitigate and adapt to some of these challenges. Methods assessing environmental impact such as life-cycle assessment (LCA) can provide estimations of the potential of such levers. Yet, there is currently no consensus as to whether and how to account for SOC variation in agricultural LCA. In this study, an LCA of a crop-livestock farm located in southern Wallonia, Belgium was performed out of 16 environmental impact categories. The impacts induced by the entire production of the farm in 2021 as well as the relative contribution of the different farm’s processes have therefore been quantified. Furthermore, a range of the farm’s SOC variation was estimated using data from soil sampling campaigns as well as from two stations of the Integrated Carbon Observation System (ICOS) network, one of these stations being located at the studied farm. The results show that the climate impact of the farm’s animal production amounts to 10,2 kg of CO2-equivalent per kg of liveweight and the associated SOC variation ranges between increasing this footprint by 2% and offsetting it by -22%. This study also highlights the challenges faced with integrating SOC variation into agricultural LCAs.