Phosphorus dynamics in the drilosphere: Unraveling earthworm-mediated soil biogeochemistry

The drilosphere, encompassing soil zones influenced by earthworm activities, represents a crucial biogeochemical hotspot for phosphorus (P) cycling and soil health. While earthworms are recognized for their positive impacts on soil P dynamics through feeding, burrowing, and casting activities, comprehensive understanding of P cycling mechanisms within the drilosphere and their relative importance across different soil environments remains limited. This review synthesized recent advances through four interconnected domains. First, we examined drilosphere formation and characteristics, revealing how earthworm ecosystem engineering creates distinct biogeochemical zones through burrow construction, mucus secretion, and cast deposition. Second, we analyzed P transformation mechanisms within the drilosphere, documenting how burrowing and casting pathways mobilize P through competitive adsorption, enzymatic mineralization, and microbial regulation. Third, we characterized the drilosphere’s contribution to terrestrial P cycling, demonstrating distinctive outward P diffusion patterns compared to rhizosphere inward movement and examining ecosystem-scale impacts. Fourth, we discussed emerging imaging techniques that offer unprecedented opportunities to visualize drilosphere P dynamics, though systematic applications remain limited. Our analysis identified critical research frontiers in micro-interfacial characterizations, biogeographical patterns, climate change impacts, and agricultural applications, providing a framework for advancing sustainable soil management strategies that leverage earthworm-mediated P mobilization.