Overview
- The study published June 12, 2026 used more than 16,000 soil cores and machine learning to produce the first global map of arbuscular mycorrhizal hyphal density in the top 15 cm of soil.
- Researchers report an average of about four meters of fungal hyphae per cubic centimeter of topsoil and estimate a total length of roughly 110 billiarden kilometers if laid end to end.
- The living hyphae hold an estimated ~300 million tonnes of carbon and the broader fungal networks are estimated to bind about one billion tonnes of carbon in the upper 15 cm.
- Grasslands and wetlands emerged as the densest hotspots, while agricultural soils show an average 47.3 percent lower hyphal density likely linked to tillage and fertiliser use.
- The study is limited to the top 15 cm of soil and uses model extrapolation, leaving open questions about deeper pools, ecosystem-specific functions and how land management could protect or restore this hidden infrastructure.