The diffusive gradients in thin-films (DGT) technique was originally developed for use in natural waters to measure the elusive “free” trace metal ion. It was quickly adapted for use in aquatic sediments and soils to measure trace metal and phosphorus fluxes, and the first scientific article reporting its use in soils was submitted for publication 25 years ago. The technique showed early promise as a reliable measurement of plant available trace metal in soils and it was first used for that purpose on Aotearoa soils in the late 2000s. It has since been adapted to measure a variety of different analytes, in expanded dimensionality and simultaneously with measurements of other dynamic soil variables (e.g. pH, enzyme activity). The insight gained in the last quarter of a century of DGT research will be used to re-examine some of the early assumptions about the information it can provide. The presentation will go on to highlight some new and interesting applications for both applied and theoretical soil scientists in Aotearoa. There are clearly important challenges to understanding what the results of DGT measurements in some soils represent. However, increased knowledge of processes that influence the supply of nutrients and trace elements to DGT presents new opportunities to investigate biogeochemical cycling in soils in ways that are not possible with most other techniques. This provides interesting prospects for future soil research where the technique can play a unique and important role
