Critical Zone Processes and Observatories for Advancing Soil Security

Critical Zone Science (CZS) provides an integrated understanding of interactions among soil, water, rock, atmosphere and biota, while Soil Security offers a complementary framework for evaluating soils through the dimensions of Capability, Condition, Capital, Connectivity and Codification. However, the relationship between Critical Zone (CZ) processes and these dimensions, and the extent to which Soil Security is represented within Critical Zone Observatories (CZOs), remain insufficiently articulated. This review examines relationships between major Critical Zone processes and the five Soil Security dimensions, assesses their documented representation across 62 CZOs and associated long-term monitoring-site entries, and identifies opportunities for strengthening their integration. The study combined a conceptual synthesis of the relevant literature with a structured desk-based assessment using an established historical inventory of 62 entries, supplemented by information from individual CZOs and institutional websites and associated publications. Each entry was evaluated against predefined evidence criteria for the five Soil Security dimensions using binary coding. Condition was documented most frequently (55/62; 88.7%), followed by Capital (42/62; 67.7%), Capability (33/62; 53.2%), Connectivity (32/62; 51.6%) and Codification (7/62; 11.3%). The findings show that CZOs activities provide substantial process-based evidence relevant to the biophysical dimensions of Soil Security, while societal and institutional dimensions, particularly Codification, are less consistently documented. Integrating Soil Security with CZOs research can therefore complement established strengths in long-term CZ observation by strengthening interpretation of soil functions and natural capital and by promoting greater attention to stakeholder engagement, knowledge exchange, stewardship and pathways for translating scientific evidence into institutional decision-making. This integration provides a basis for connecting understanding of how the CZ functions with how soil resources are valued, stewarded and governed.