X-ray microtomography to investigate thin layers of soil clod

Macedo, Álvaro; Crestana, Sı́lvio; Vaz, C. M. P.

doi:10.1016/s0167-1987(98)00180-9

Cited by 37 publications

(18 citation statements)

References 11 publications

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“…X-ray CT investigations of the physical properties of different soils affected by agricultural practices have been performed by Olsen and Børresen (1997), Wiermann et al (2000), Gantzer and Anderson (2002), Rogasik et al (2003) etc. Aspects related to the process of soil surface sealing due to raindrop impact have been evaluated by Macedo et al (1998) and Fohrer et al (1999). Øygarden et al (1997) combined field investigations and X-ray CT imagery to characterize the structure of an artificially levelled soil.…”

Section: Characterization Of Soil Physical Propertiesmentioning

confidence: 99%

Application of X-ray computed tomography to soil science: A literature review

Taina¹,

Heck²,

Elliot³

2008

Can. J. Soil. Sci.

265

128

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T. R. 2008. Application of X-ray computed tomography to soil science: A literature review. Can. J. Soil Sci. 88: 1Á20. The study of the spatial configuration of soil, in its complexity, requires an understanding of the interrelations and interactions between the diverse soil constituents, at various levels of organization. Investigations of the spatial arrangement of the mineral and organic components of soil have benefited from the development of techniques for structural analysis. X-ray computed tomography (CT) is a non-destructive and non-invasive technique that has been successfully used for three-dimensional (3D) examination of soil. Valuable information has been obtained by the application of CT for the description and quantitative measurements of soil structure elements, especially of soil pores and pore network features. In many studies, X-ray CT has been used to investigate the hydro-physical characteristics of the soil, in a functional and temporal manner. A dynamic approach has also been utilized in the evaluation of the biotic factor influence on soil. The analysis of soil solid phases, by X-ray CT, has been challenging due to the similar X-ray attenuation of different solid constituents. However, the use of multiple X-ray energy levels has facilitated the discrimination of minerals in soil. The aim of this review and synthesis is to offer a perspective on the major issues related to application of the technique, general attempted solutions and possible directions in the utilization of X-ray CT in soil research. Relevant scanning parameters, procedures for CT image reconstruction, algorithms for the quantification of soil characteristics and results are presented for each type of application.Key words: X-ray computed tomography, energy level, spatial resolution, segmentation, soil mineral and organic constituents, soil physical and hydro-physical properties, soil biota Taina, I. A., Heck, R. J. et Elliot, T. R. 2008. Application de la tomographie aux rayons X a`la science du sol : survol de la litte´rature. Can. J. Soil Sci. 88: 1Á20. Pour e´tudier la configuration spatiale du sol dans toute sa complexite´, il faut comprendre les relations et les interactions des fractions du sol a`diffe´rents niveaux d'organisation. Les recherches sur l'organisation spatiale des couches mine´rales et organiques du sol ont profite´du de´veloppement de techniques d'analyse structurale. La tomographie aux rayons X assiste´e par ordinateur (TXAO) est une technique non destructive et non invasive qu'on a applique´e avec succe`s a`l'analyse tridimensionnelle du sol. L'usage de la TXAO pour de´crire et quantifier les e´le´ments structuraux du sol, surtout les pores et les particularite´s de leurs re´seaux, a permis de glaner quelques pre´cieuses informations. Maintes e´tudes rapportent qu'on s'est servi de la TXAO pour pre´ciser les proprie´te´s hydrophysiques du sol sur le plan fonctionnel ou temporel. On a aussi recouru a`une approche dynamique pour e´valuer l'influence des facteurs biotiques sur le sol. L'analyse des p...

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Section: Characterization Of Soil Physical Propertiesmentioning

confidence: 99%

Application of X-ray computed tomography to soil science: A literature review

Taina¹,

Heck²,

Elliot³

2008

Can. J. Soil. Sci.

265

128

View full text Add to dashboard Cite

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“…Computed microtomography (CMT) can be viewed as a technique in soil studies that enables examination of local variation (micrometer scale), whereas conventional tomography enables examination at a millimeter scale (Macedo et al, 1998). Computed microtomography has been used in examination of pores in sealing materials for nuclear waste and in rock and soil media as well as evaluation of fluid transport; in addition, pore dynamics and bacterial and root studies have been reported (Coles et al, 1998;Kozaki et al, 2001;Lindquist, 2002;Gregory et al, 2003;Thieme et al, 2003;Udawatta et al, 2008;Peth et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Synchrotron microtomographic quantification of geometrical soil pore characteristics affected by compaction

Udawatta

Gantzer

Anderson

et al. 2016

SOIL

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Abstract. Soil compaction degrades soil structure and affects water, heat, and gas exchange as well as root penetration and crop production. The objective of this study was to use X-ray computed microtomography (CMT) techniques to compare differences in geometrical soil pore parameters as influenced by compaction of two different aggregate size classes. Sieved (diameter < 2 mm and < 0.5 mm) and repacked (1.51 and 1.72 Mg m −3 ) Hamra soil cores of 5 by 5 mm (average porosities were 0.44 and 0.35) were imaged at 9.6 µm resolution at the Argonne Advanced Photon Source (synchrotron facility) using X-ray CMT. Images of 58.9 mm 3 volume were analyzed using 3-Dimensional Medial Axis (3-DMA) software. Geometrical characteristics of the spatial distributions of pore structures (pore radii, volume, connectivity, path length, and tortuosity) were numerically investigated. Results show that the coordination number (CN) distribution and path length (PL) measured from the medial axis were reasonably fit by exponential relationships P(CN) = 10 −CN/Co and P(PL) = 10 −PL/PLo , respectively, where Co and PLo are the corresponding characteristic constants. Compaction reduced porosity, average pore size, number of pores, and characteristic constants. The average pore radii (63.7 and 61 µm; p < 0.04), largest pore volume (1.58 and 0.58 mm 3 ; p = 0.06), number of pores (55 and 50; p = 0.09), and characteristic coordination number (3.74 and 3.94; p = 0.02) were significantly different between the low-density than the high-density treatment. Aggregate size also influenced measured geometrical pore parameters. This analytical technique provides a tool for assessing changes in soil pores that affect hydraulic properties and thereby provides information to assist in assessment of soil management systems.

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“…Phogat and Aylmore [6] made direct measurements of the spatial distribution of soil macroporosity. Macedo et al [7] presented a CT scanner and a methodology for soil investigation at the microscale. Clausnitzer and Hopmans [2] proposed a method to determine the phase-volume fractions in tomographic representations of two-phase systems.…”

Section: Introductionmentioning

confidence: 99%

Representative Gamma-ray Computed Tomography Calibration for Applications in Soil Physics

et al. 2011

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Tomographic image quality in soil physics applications is extremely dependent on calibration. Here, good calibrations of the system are necessary to avoid errors during soil evaluations by computed tomography (CT), which can hamper interpretations of physical parameters of the soil. In order to analyze the relevance of a good calibration curve (CC) for measurements of soil physical properties, determinations of soil bulk density (ρ b ) were obtained using four different CCs established for a homemade CT scanner dedicated especially to soil physics. The calibrations of the system were obtained through the relationship between tomographic units and corresponding linear attenuation coefficients (μ 1 ) of different materials. Data show that different calibration curves produce distinct ρ b values affecting the quality of results of this soil physical property when evaluated by CT. However, it was demonstrated that even using non-homogeneous materials for CT calibration the results of ρ b practically are of the same order of magnitude of the whole system error estimated in 0.05 g cm −3 (taking the water as reference).

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X-ray microtomography to investigate thin layers of soil clod

Cited by 37 publications

References 11 publications

Application of X-ray computed tomography to soil science: A literature review

Application of X-ray computed tomography to soil science: A literature review

Synchrotron microtomographic quantification of geometrical soil pore characteristics affected by compaction

Representative Gamma-ray Computed Tomography Calibration for Applications in Soil Physics

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