Exploring human-nature relationships in academic literature on the nitrogen cycle

The nitrogen (N) cycle is a familiar concept. As is the much simplified, often diagrammatic, representation commonly used to illustrate the scale, importance and interconnectedness of this global cycle that links air, water, rocks and living beings. However, in this representation, humans are often presented as a seemingly minor entity or not explicitly shown at all. This can obscure the idea that humanity is both a direct beneficiary of the nitrogen cycle (through food and resources) and an increasingly significant influence on its function. This study sought to understand how diverse Human-Nature relationships (HNR) are expressed in recent academic literature on the nitrogen cycle. A sample of peer-reviewed literature, containing explicit and inferred examples of HNR and the nitrogen cycle, was analysed using two approaches: 1) network analysis, identifying and illustrating all quantifiable links made between components of the nitrogen cycle, and 2) content analysis to understand how different kinds of terminology were being used to describe relationships between components in the cycle. The network analysis revealed diverse links between 'human' and 'non-human nature'. The content analysis found some explicit use of relational terms, most commonly 'depend*'. Both approaches highlighted strongly reciprocal links within the 'human' realm and the explicit centrality in which this is held across the corpus. We demonstrate the utility of combining quantitative and qualitative analysis to understand nuanced relationships in the nitrogen cycle and explore the utility this has to increase the acknowledgement and appreciation of HNR in science communication and science-policy interface work. A network analysis of nitrogen flows empirically quantified in the scientific literature showed a prominence of human components in the nitrogen cycle and how they are connected to different atmospheric, aquatic and terrestrial non-human components.A qualitative content analysis of the same scientific literature also showed the prominent role of human activities within the nitrogen cycle, while revealing a wide acknowledgement of relationships between humans and non-human nature.Integrated knowledge on the strength and nature of those relationships is still needed to better inform policy.Our mixed approach can be applied for other biogeochemical cycles that are key for global ecosystem functioning.