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Root induced soil deformation influences Fe, S and P: rhizosphere chemistry investigated using synchrotron XRF and XAS

Root induced soil deformation influences Fe, S and P: rhizosphere chemistry investigated using synchrotron XRF and XAS
Root induced soil deformation influences Fe, S and P: rhizosphere chemistry investigated using synchrotron XRF and XAS
Rhizosphere soil has distinct physical and chemical properties from bulk soil. However, besides root induced physical changes, chemical changes have not been extensively measured in situ on the pore scale.

In this study we couple structural information, previously obtained using synchrotron X-ray computed tomography (XCT), with synchrotron X-ray Fluorescence (SR-XRF) microscopy and X-ray Absorption Near-Edge Structure (XANES) to unravel chemical changes induced by plant roots.
Our results suggest that iron (Fe) and sulfur (S) increase notably in the direct vicinity of the root via solubilization and microbial activity. XANES further shows that Fe is slightly reduced, S is increasingly transformed into sulfate (SO42-) and that P is increasable adsorbed to humic substances in this enrichment zone. In addition, the ferrihydrite fraction decreases drastically suggesting the preferential dissolution and the formation of more stable Fe-oxides. Additionally, the increased transformation of organic S to sulfate indicates that the microbial activity in this zone is increased. These changes in soil chemistry correspond to the soil compaction zone as previously measured via X-ray CT.
The fact that these changes are co-located near the root and the compaction zone suggests that decreased permeability due to soil structural changes acts as a barrier creating a zone with increased rhizosphere chemical interactions via surface mediated processes, microbial activity and acidification.
Fe, S, P, rhizosphere chemistry, synchrotron, X-ray Fluorescence, XANES, sulfate, phosphate
0028-646X
Van Veelen, Arjen
cb6f2c8b-4671-4836-88a0-3987fd2f2d67
Koebernick, Nicolai
118c4e45-02d8-42da-84c8-8ee4fac140ad
Scotson, Callum S.
47901c28-548c-41cc-9cbd-f0429a24c7cb
McKay Fletcher, Daniel
60e9adeb-182b-4dfd-846a-b684f8e2358e
Huthwelker, Thomas
65a9fbba-ce44-4d97-a7d8-57567e622e23
Borca, Camelia N.
2ab1a507-4a9a-458e-98c2-01da8e7c235b
Mosselmans, Fred W.
186e47ae-2987-407b-b8f8-0dc2119adcdd
Roose, Tiina
3581ab5b-71e1-4897-8d88-59f13f3bccfe
Van Veelen, Arjen
cb6f2c8b-4671-4836-88a0-3987fd2f2d67
Koebernick, Nicolai
118c4e45-02d8-42da-84c8-8ee4fac140ad
Scotson, Callum S.
47901c28-548c-41cc-9cbd-f0429a24c7cb
McKay Fletcher, Daniel
60e9adeb-182b-4dfd-846a-b684f8e2358e
Huthwelker, Thomas
65a9fbba-ce44-4d97-a7d8-57567e622e23
Borca, Camelia N.
2ab1a507-4a9a-458e-98c2-01da8e7c235b
Mosselmans, Fred W.
186e47ae-2987-407b-b8f8-0dc2119adcdd
Roose, Tiina
3581ab5b-71e1-4897-8d88-59f13f3bccfe

Van Veelen, Arjen, Koebernick, Nicolai, Scotson, Callum S., McKay Fletcher, Daniel, Huthwelker, Thomas, Borca, Camelia N., Mosselmans, Fred W. and Roose, Tiina (2019) Root induced soil deformation influences Fe, S and P: rhizosphere chemistry investigated using synchrotron XRF and XAS. New Phytologist. (doi:10.1111/nph.16242).

Record type: Article

Abstract

Rhizosphere soil has distinct physical and chemical properties from bulk soil. However, besides root induced physical changes, chemical changes have not been extensively measured in situ on the pore scale.

In this study we couple structural information, previously obtained using synchrotron X-ray computed tomography (XCT), with synchrotron X-ray Fluorescence (SR-XRF) microscopy and X-ray Absorption Near-Edge Structure (XANES) to unravel chemical changes induced by plant roots.
Our results suggest that iron (Fe) and sulfur (S) increase notably in the direct vicinity of the root via solubilization and microbial activity. XANES further shows that Fe is slightly reduced, S is increasingly transformed into sulfate (SO42-) and that P is increasable adsorbed to humic substances in this enrichment zone. In addition, the ferrihydrite fraction decreases drastically suggesting the preferential dissolution and the formation of more stable Fe-oxides. Additionally, the increased transformation of organic S to sulfate indicates that the microbial activity in this zone is increased. These changes in soil chemistry correspond to the soil compaction zone as previously measured via X-ray CT.
The fact that these changes are co-located near the root and the compaction zone suggests that decreased permeability due to soil structural changes acts as a barrier creating a zone with increased rhizosphere chemical interactions via surface mediated processes, microbial activity and acidification.

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Roothairs3_final_accepted_NOMARKUP - Accepted Manuscript
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More information

Accepted/In Press date: 27 September 2019
e-pub ahead of print date: 7 October 2019
Keywords: Fe, S, P, rhizosphere chemistry, synchrotron, X-ray Fluorescence, XANES, sulfate, phosphate

Identifiers

Local EPrints ID: 435449
URI: http://eprints.soton.ac.uk/id/eprint/435449
ISSN: 0028-646X
PURE UUID: 38b57cfd-2d98-4fce-b90f-3aa24e9c8c4f
ORCID for Tiina Roose: ORCID iD orcid.org/0000-0001-8710-1063

Catalogue record

Date deposited: 06 Nov 2019 17:30
Last modified: 18 Feb 2021 17:11

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