Abstract
Soils hold more carbon (C) in soil organic matter (SOM) than vegetation and the atmosphere combined, and only a small loss of this C can exacerbate climate change. Recent advances highlight the importance of root C inputs and interactions between roots, microbes, and soil minerals in forming stable SOM. Yet, despite understanding these general mechanisms, we still have limited understanding of the role of root systems and their strategies, and the microbial identities that process belowground root litter and exudate inputs. Moreover, we do not know how these interactions respond to a changing climate. Here, we will resolve these knowledge gaps by connecting recent advances in our understanding of SOM stabilisation with recent advances in root economics to conceptualise and test how plants with different root systems affect the formation and stabilisation of soil organic matter (SOM). Our overarching aim is to advance our fundamental understanding of the role of root systems, microbes, soil mineralogy and aggregation in the formation and stabilisation of soil organic C, and to apply this understanding in real-world grassland systems. Using Dutch grasslands as a model system, we will identify agronomically relevant grassland species and species assemblages that increase the stabilisation of SOM and minimise greenhouse gas emissions, under current and future climates. We will do this by setting up – together with farmers and stakeholders – a network of field experiments in Dutch grasslands, combined with a range of mechanistic experiments. The resulting fundamental understanding, combined with results from the field experiments, will allow for regional- and national-scale projections of soil C sequestration rates and greenhouse gas emissions under current and future climates.
Netherlands