Mapping Phosphorus Availability in Soil at a Large Scale and High Resolution Using Novel Diffusive Gradients in Thin Films Designed for X-ray Fluorescence Microscopy

Claudia Moens, Enzo Lombi, Daryl L. Howard, Stefan Wagner, Justin L. Payne, Peter M. Kopittke, Casey L. Doolette

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung


A novel binding layer (BL) as part of the diffusive gradients in thin films (DGT) technique was developed for the two-dimensional visualization and quantification of labile phosphorus (P) in soils. This BL was designed for P detection by synchrotron-based X-ray fluorescence microscopy (XFM). It differs from the conventional DGT BL as the hydrogel is eliminated to overcome the issue that the fluorescent X-rays of P are detected mainly from shallow sample depths. Instead, the novel design is based on a polyimide film (Kapton) onto which finely powdered titanium dioxide-based P binding agent (Metsorb) was applied, resulting in superficial P binding only. The BL was successfully used for quantitative visualization of P diffusion from three conventional P fertilizers applied to two soils. On a selection of samples, XFM analysis was confirmed by quantitative laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The XFM method detected significant differences in labile P concentrations and P diffusion zone radii with the P fertilizer incubation, which were explained by soil and fertilizer properties. This development paves the way for fast XFM analysis of P on large DGT BLs to investigate in situ diffusion of labile P from fertilizers and to visualize large-scale P cycling processes at high spatial resolution.
Seiten (von - bis)440-448
FachzeitschriftEnvironmental science & technology
PublikationsstatusVeröffentlicht - 18 Dez. 2023

Bibliographische Notiz

Funding Information:
This research was performed on the XFM beamline at the Australian Synchrotron, part of ANSTO. This work was funded by the Grains Research and Development Corporation (GRDC), Project USA1910-001RTX. The authors acknowledge funding provided to S.W. by the Austrian Science Fund (FWF, P30085-N28, project lead: Thomas Prohaska). They thank Professor Jakob Santner for his advice on the polyurethane DGT preparation. They also acknowledge Susie Ritch for technical assistance and Dr. Euan Smith for providing the 3D printed materials for DGT assemblies.

Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society.

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