Priming and organic carbon stability in soil parent materials

Over the past decade, both national (UK) and multilateral (EU) climate legislation have significantly accelerated research efforts to mitigate soil carbon emissions, enhance soil organic carbon (OC) sequestration, and promote long-term OC storage. However, these efforts face substantial challenges. Increasing demands on land use and the resulting land-cover changes often lead to significant net losses of OC. Furthermore, climate warming exacerbates OC losses through accelerated decomposition processes. Although the soil carbon reservoir has a finite capacity, its potential is limited by an arbitrary boundary: the lower limit of soil profiles, separating them from the underlying zone of soil parent material. Soil parent materials consist of consolidated substrates (e.g., weathered rock) and unconsolidated ones (e.g., alluvium) from which soils primarily develop. Emerging evidence indicates that soil parent materials has stores of biogenic organic carbon. However, our understanding of the stability of carbon at the interface between soil parent materials and soils remains limited. This presentation explores the stability of organic carbon within soil parent materials, focusing specifically on the effects of priming on OC stability.