The datasets originate from a field experiment designed to assess the mobility and longevity of DNA in a soil environment. We applied radish DNA - in the form of leaves (solid treatment) and PCR product (liquid treatment) to experimental plots in southern Iceland. We sampled the soil from different depths under the plots over a period of 15 months, looking for traces of radish DNA. The dataset encompasses 1) DNA metabarcoding data (plants) derived from soil samples; 2) a survey of extant plant communities; 3) a record of near-surface soil temperatures for the duration of the experiment; and 4) data quantifying the decomposition of radish leaves applied to the plots. The radish DNA was applied to six experimental plots in June 2023; soil samples were collected from below the plots in May 2024 (M24) and October 2024 (O24). DNA extraction and PCR was conducted by Dr Doreen Huang (University of Southampton). DNA from the soil samples was sequenced by a commercial third party (Novogene). Full details about this dataset can be found at https://doi.org/10.5285/7c6cbb74-96ad-4269-bad7-51025963ef23