This dataset includes measurements of carbon-14 transfer from plants to soil within mesh cores. Measurements were taken in roots, shoots, soil and from respiration. Mesh cores were either static or rotated to provide plus and minus mycorrhizal mycelial systems. Carbon-14 was traced through cores as respiration using KOH (Potassium hydroxide) traps. The experiment was carried out at the University of Sheffield using soil from the NERC Soil Biodiversity site in Scotland. The work was part of the NERC Soil Biodiversity Thematic Programme, which was established in 1999 and was centred upon the intensive study of a large field experiment located at the Macaulay Land Use Research Institute (now the James Hutton Institute) farm at Sourhope in the Scottish Borders. During the experiment, the site was monitored to assess changes in above-ground biomass production (productivity), species composition and relative abundance (diversity). Full details about this nonGeographicDataset can be found at https://doi.org/10.5285/39b8bd96-af67-4f61-a040-0682043df938