X-ray computed tomography imaging of solute movement through ridged and flat plant systems
X-ray computed tomography imaging of solute movement through ridged and flat plant systems
The aim of this investigation was to experimentally compare the movement of a solute through soils with two field-representative surface geometries: ridge and furrow surfaces versus flat surfaces. X-ray computed tomography (XCT) imaging was undertaken to trace the movement of a soluble iodinated contrast medium, here used as an XCT-visible analogue for field-applied solutes, through soil columns with either a ridge and furrow or flat soil surface geometry. In addition to the soil surface geometry, the experimental treatments included the presence or absence of plants and surface water ponding. Experimental results were compared to existing numerical simulations adapted to represent the present experimental column systems. Similar infiltration patterns were observed in imaging results and the numerical simulations for most treatments. The experimental results suggest that plant roots present a significant localized effect to reduce the infiltration depth of solutes, particularly in planted ridges where the infiltration depth of the contrast medium was minimal. There is variability within the results because the number of replicates was limited to three due to the exploratory nature of the study (testing eight different treatments) and the cost and availability of XCT facilities capable of imaging such physically large samples. Discrepancies between the imaged infiltration depth of the solute and the numerical simulations are attributed to variation in plant root distribution and also spatial soil moisture, as measured using resistive soil moisture sensing. The results of this investigation elucidate the nature of solute movement through soil surface geometries, indicating that plant root water uptake can reduce solute infiltration depth, but surface ponding can negate this. These results suggest that soil surface shape, plant age and the timing of solute application with anticipated rainfall could be important considerations for reducing solute leaching and improving solute application efficiency. Highlights: Investigating factors affecting solute infiltration in flat or ridge and furrow soil geometries. X-ray CT imaging traces soluble contrast media movement in soil columns and is compared to modelling. Plant root water uptake can reduce solute infiltration depth, but surface ponding can negate this. Considering soil surface shape, rain and plant age in solute application could reduce leaching.
X-ray CT, contrast agent, ridge and furrow cultivation, soil
198-214
Scotson, Callum, Paul
47901c28-548c-41cc-9cbd-f0429a24c7cb
Duncan, Simon
fa8481c1-3788-41a0-a304-02515b93ef7d
Williams, Katherine
a13f30b4-2f53-4a14-ad38-c733923a6450
Ruiz, Siul Aljadi
d79b3b82-7c0d-47cc-9616-11d29e6a41bd
Roose, Tiina
3581ab5b-71e1-4897-8d88-59f13f3bccfe
January 2021
Scotson, Callum, Paul
47901c28-548c-41cc-9cbd-f0429a24c7cb
Duncan, Simon
fa8481c1-3788-41a0-a304-02515b93ef7d
Williams, Katherine
a13f30b4-2f53-4a14-ad38-c733923a6450
Ruiz, Siul Aljadi
d79b3b82-7c0d-47cc-9616-11d29e6a41bd
Roose, Tiina
3581ab5b-71e1-4897-8d88-59f13f3bccfe
Scotson, Callum, Paul, Duncan, Simon, Williams, Katherine, Ruiz, Siul Aljadi and Roose, Tiina
(2021)
X-ray computed tomography imaging of solute movement through ridged and flat plant systems.
European Journal of Soil Science, 72 (1), .
(doi:10.1111/ejss.12985).
Abstract
The aim of this investigation was to experimentally compare the movement of a solute through soils with two field-representative surface geometries: ridge and furrow surfaces versus flat surfaces. X-ray computed tomography (XCT) imaging was undertaken to trace the movement of a soluble iodinated contrast medium, here used as an XCT-visible analogue for field-applied solutes, through soil columns with either a ridge and furrow or flat soil surface geometry. In addition to the soil surface geometry, the experimental treatments included the presence or absence of plants and surface water ponding. Experimental results were compared to existing numerical simulations adapted to represent the present experimental column systems. Similar infiltration patterns were observed in imaging results and the numerical simulations for most treatments. The experimental results suggest that plant roots present a significant localized effect to reduce the infiltration depth of solutes, particularly in planted ridges where the infiltration depth of the contrast medium was minimal. There is variability within the results because the number of replicates was limited to three due to the exploratory nature of the study (testing eight different treatments) and the cost and availability of XCT facilities capable of imaging such physically large samples. Discrepancies between the imaged infiltration depth of the solute and the numerical simulations are attributed to variation in plant root distribution and also spatial soil moisture, as measured using resistive soil moisture sensing. The results of this investigation elucidate the nature of solute movement through soil surface geometries, indicating that plant root water uptake can reduce solute infiltration depth, but surface ponding can negate this. These results suggest that soil surface shape, plant age and the timing of solute application with anticipated rainfall could be important considerations for reducing solute leaching and improving solute application efficiency. Highlights: Investigating factors affecting solute infiltration in flat or ridge and furrow soil geometries. X-ray CT imaging traces soluble contrast media movement in soil columns and is compared to modelling. Plant root water uptake can reduce solute infiltration depth, but surface ponding can negate this. Considering soil surface shape, rain and plant age in solute application could reduce leaching.
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Accepted/In Press date: 1 May 2020
e-pub ahead of print date: 6 May 2020
Published date: January 2021
Additional Information:
Funding Information:
C.P.S., K.W. and T.R. are funded by ERC Consolidator grant 646809 (Data Intensive Modelling of Rhizosphere Processes). S.J.D. is funded by BBSRC Syngenta Case PhD Studentship BB/L5502625/1. S.R. and T.R. are funded by BBSRC SARIC BB/P004180/1. T.R. is also funded by EPSRC EP/M020355/1 and NERC NE/L00237/1. The authors acknowledge the ?-VIS X-ray Imaging Centre at the University of Southampton for provision of tomographic imaging facilities, supported by EPSRC grant EP-H01506X. The authors would also like to acknowledge Davey Jones (Bangor University) for providing the soil used within this investigation and Max Smith for providing a Raspberry Pi.
Publisher Copyright:
© 2020 The Authors. European Journal of Soil Science published by John Wiley & Sons Ltd on behalf of British Society of Soil Science.
Keywords:
X-ray CT, contrast agent, ridge and furrow cultivation, soil
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Local EPrints ID: 441038
URI: http://eprints.soton.ac.uk/id/eprint/441038
ISSN: 1351-0754
PURE UUID: 8250f692-6a14-4d8c-b9ab-be3631798c73
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Date deposited: 28 May 2020 16:57
Last modified: 17 Mar 2024 05:35
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Author:
Callum, Paul Scotson
Author:
Simon Duncan
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