Menon, M., Jia, X., Lair, G.J. et al. (2 more authors) (2015) Analysing the impact of compaction of soil aggregates using X-ray microtomography and water flow simulations. Soil and Tillage Research, 150. 147 - 157. ISSN 0167-1987
Abstract
Soil aggregates are structural units of soil, which create complex pore systems controlling gas and water storage and fluxes in soil. Aggregates can be destroyed during swelling and shrinking or by external forces like mechanical compaction and yet, the knowledge of how physical impact alters aggregate structure remains limited. The aim of the study was to quantify the impact of compaction on macroaggregates, mainly on the pore size distribution and water flow. In this study, aggregates (2-5mm) were collected by dry sieving in grassland of the Fuchsenbigl-Marchfeld Critical Zone Observatory (Austria). The structural alterations of these soil aggregates under controlled compaction were investigated with a non-invasive 3D X-ray microtomography (XMT). The detailed changes in pore size distribution between aggregates (interpores, diameter >90μm) and within the aggregates (intrapores, diameter ≤90μm) in pre- and post-compacted soils were revealed at two soil moisture (9.3% and 18.3% w/w) and two bulk density increments (0.28 and 0.71gcm-3 from the initial values). The soil permeability was simulated using lattice Boltzmann method (LBM) based on 3D images. Soil compaction significantly reduced total pores volume and the proportion of interpores volume and surface area, while total pore surface area and the proportion of intrapores volume and surface area increased. The increases in soil moisture tended to reduce the effects of compaction on interpores and intrapores, while the high compaction increment drastically changed the pore size distribution. The aggregate compaction decreased water penetration potential due to the increase of small intra-aggregate pores and cavities as demonstrated by LBM. Notably, the LBM results showed a significant linear correlation between the water flow rate and bulk density of soil aggregates and predicted that the water flow could be reduced by up to 97-99% at bulk density of ≥1.6gcm-3 with soil water content of 18.3% w/w. Thus, a combination of imaging and modelling provided new insights on the compaction effects on aggregates, underpinning the importance of protecting soil structure from mechanical compaction to minimise environmental impacts of soil compaction and maintain water infiltration and percolation in arable soils.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015 Elsevier B.V. All rights reserved. |
Keywords: | Lattice Boltzmann; Modelling; Soil aggregates; Soil compaction; Water flow; X-ray microtomography |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Civil and Structural Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 30 Apr 2015 10:15 |
Last Modified: | 08 Aug 2015 21:30 |
Published Version: | http://dx.doi.org/10.1016/j.still.2015.02.004 |
Status: | Published |
Publisher: | Elsevier |
Refereed: | Yes |
Identification Number: | 10.1016/j.still.2015.02.004 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:84899 |