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| Titel |
3D Structure of Tillage Soils |
| VerfasserIn |
Iván González-Torre, Juan Carlos Losada, Ruth Falconer, Simona Hapca, Ana M. Tarquis |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250114525
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| Publikation (Nr.) |
 EGU/EGU2015-15313.pdf |
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| Zusammenfassung |
| Soil structure may be defined as the spatial arrangement of soil particles, aggregates and
pores. The geometry of each one of these elements, as well as their spatial arrangement, has a
great influence on the transport of fluids and solutes through the soil. Fractal/Multifractal
methods have been increasingly applied to quantify soil structure thanks to the advances in
computer technology (Tarquis et al., 2003).
There is no doubt that computed tomography (CT) has provided an alternative for
observing intact soil structure. These CT techniques reduce the physical impact to sampling,
providing three-dimensional (3D) information and allowing rapid scanning to study sample
dynamics in near real-time (Houston et al., 2013a). However, several authors have dedicated
attention to the appropriate pore-solid CT threshold (Elliot and Heck, 2007; Houston et al.,
2013b) and the better method to estimate the multifractal parameters (Grau et al., 2006;
Tarquis et al., 2009).
The aim of the present study is to evaluate the effect of the algorithm applied in the
multifractal method (box counting and box gliding) and the cube size on the calculation of
generalized fractal dimensions (Dq) in grey images without applying any threshold. To this
end, soil samples were extracted from different areas plowed with three tools (moldboard,
chissel and plow). Soil samples for each of the tillage treatment were packed into
polypropylene cylinders of 8 cm diameter and 10 cm high. These were imaged
using an mSIMCT at 155keV and 25 mA. An aluminium filter (0.25 mm) was
applied to reduce beam hardening and later several corrections where applied during
reconstruction.
References
Elliot, T.R. and Heck, R.J. 2007. A comparison of 2D and 3D thresholding of CT
imagery. Can. J. Soil Sci., 87(4), 405-412.
Grau, J, Médez, V.; Tarquis, A.M., Saa, A. and Díaz, M.C.. 2006. Comparison of
gliding box and box-counting methods in soil image analysis. Geoderma, 134,
349-359.
González-Torres, Iván. Theory and application of multifractal analysis methods in images
for the study of soil structure. Master thesis, UPM, 2014.
Houston, A.N.; S. Schmidt, A.M. Tarquis, W. Otten, P.C. Baveye, S.M. Hapca. Effect of
scanning and image reconstruction settings in X-ray computed tomography on
soil image quality and segmentation performance. Geoderma, 207-208, 154-165,
2013a.
Houston, A, Otten, W., Baveye, Ph., Hapca, S. Adaptive-Window Indicator Kriging: A
Thresholding Method for Computed Tomography, Computers & Geosciences, 54, 239-248,
2013b.
Tarquis, A.M., R.J. Heck, D. Andina, A. Alvarez and J.M. Antón. Multifractal
analysis and thresholding of 3D soil images. Ecological Complexity, 6, 230-239,
2009.
Tarquis, A.M.; D. Giménez, A. Saa, M.C. Díaz. and J.M. Gascó. Scaling and
Multiscaling of Soil Pore Systems Determined by Image Analysis. Scaling Methods in Soil
Systems. Pachepsky, Radcliffe and Selim Eds., 19-33, 2003. CRC Press, Boca Ratón,
Florida.
Acknowledgements
First author acknowledges the financial support obtained from Soil Imaging Laboratory
(University of Gueplh, Canada) in 2014. |
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