Overview: ‘Global change effects on terrestrial biogeochemistry at the plant-soil interface’ 

Abstract. ‘Global change’ significantly alters organic matter and element cycling, but many of the underlying processes and consequences remain poorly understood. The interface of plants and soil plays a central role, coupling atmosphere, biosphere and lithosphere and integrating biological and geochemical processes. The contributions to this special issue tackled questions on both biotic and abiotic interactions underlying responses of terrestrial biogeochemical cycling to a range of global changes, including increases in atmospheric CO₂ concentrations, warming, drought and altered water regimes. In this this overview we provide insights into the empirical, conceptual, and modelling-based studies featured in this special issue. In the following, we synthesize key findings covering 1) responses of plants to elevated CO₂, 2) the role of soil organisms in modulating responses to warming, 3) impacts of global change on soil organic carbon, nitrogen, and mineral nutrient availability and 4) the influence of altered water table-depth caused by global change on greenhouse gas emissions (Figure 1). We showcase studies conducted in regions from the arctic to the tropics and highlight the manifold impacts of global change on various ecosystem components controlling biogeochemical processes occurring at the plant-soil interface. This understanding is crucial for deciphering feedbacks of terrestrial ecosystems to the climate system.