Sub-millimeter distribution of labile trace element fluxes in the rhizosphere explains differential effects of soil liming on cadmium and zinc uptake in maize

Erik Smolders, Stefan Wagner, Thomas Prohaska, Johanna Irrgeher, Jakob Santner

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

6 Zitate (Scopus)


Trace element concentrations in the rhizosphere were quantified to better understand why soil liming often fails to reduce cadmium (Cd) uptake by plants. Maize seedlings were grown on a soil with natural background levels of Cd and zinc (Zn). Soil liming increased soil pH from 4.9 to 6.5 and lowered the soil solution free ion activities by factor 7 (Cd) and 9 (Zn). In contrast, shoot Cd concentrations were unaffected by liming while shoot Zn concentrations were lowered by factor 1.9. Mapping of labile soil trace elements using diffusive gradients in thin films (DGT) in combination with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) revealed an almost complete depletion of Cd in the rhizosphere in all soil treatments, showing that Cd uptake is controlled by diffusion. The flux of Cd from soil to the DGT, with direct contact between the soil and the binding gel, was unaffected by liming whereas it decreased by factor 3 for Zn, closely mimicking the contrasting effects of liming on Cd and Zn bioavailability. This evidence, combined with additional flux data of freshly spiked Cd and Zn isotopes in soil and with modelling, suggests that the diffusive transport of Cd in unsaturated soil is more strongly controlled by the labile adsorbed metal concentration than by its concentration in solution. This is less the case for Zn because of its inherently slower desorption compared to Cd.
FachzeitschriftScience of the total environment
Ausgabenummer10 October
Frühes Online-Datum18 Juni 2020
PublikationsstatusVeröffentlicht - 10 Okt. 2020

Bibliographische Notiz

Funding Information:
ES wrote the manuscript during a sabbatical leave to the University of Natural Resources and Life Sciences, Vienna (BOKU), supported by grant K801219N from FWO -Vlaanderen. Technical assistance by Gerlinde Wieshammer, Sarah Mühlbacher and Christine Opper is greatly appreciated. This study was co-funded by the Austrian Science Fund (FWF): P30085-N28 (TP) and the Austrian Science Fund (FWF) and the Federal State of Lower Austria P27571-BBL (JS).

Publisher Copyright:
© 2020 The Authors

Dieses zitieren