Biogeochemical activity in soil is concentrated in hotspots created by living roots, decomposing residues, fungal networks, soil fauna, biopores, aggregates and mineral surfaces. These domains are not fixed. They emerge, overlap, shift between oxic and anoxic states, and can persist after the original plant input has ceased. The central challenge is no longer only to locate hotspots. We also need to explain how they develop, what triggers functional shifts, and when brief hot moments leave lasting effects on soils and plants.

This session focuses on feedbacks among plant inputs, microbial physiology and succession, and the physical and chemical soil environment. We welcome experimental and modelling studies of the rhizosphere, detritusphere, biopores, aggregates and other soil microhabitats, including links among them.

How do root exudates, litter and microbial residues regulate carbon and nutrient flows?

How do soil structure, water, oxygen and redox cycles control microbial growth, enzyme activity, priming and greenhouse-gas formation?

How do plant development and root death, day–night cycles, wetting and drying, climate extremes, pollution and management reshape hotspot resistance, recovery and legacy effects?

We particularly encourage spatially and temporally resolved work using enzyme and chemical imaging, microsensors, isotope tracing, tomography, microfluidics, single-cell methods, metabolomics, multi-omics or synthetic communities. Process-based and data-driven models that connect hotspot dynamics with root systems, soil profiles, fields and ecosystems are equally welcome. Contributions from agricultural, forest, grassland, wetland and restored soils are invited. Together, these contributions will help explain when short-lived, local interactions lead to persistent changes in carbon storage, nutrient availability, soil structure, greenhouse-gas emissions, plant health and ecosystem resilience.