The use of gamma ray computed tomography to investigate soil compaction due to core sampling devices

Pires, Luiz F.; Arthur, Robson Clayton Jacques; Correchel, Vládia; Bacchi, Osny Oliveira Santos; Reichardt, Klaus; Brasil, René Porfirio Camponez do

doi:10.1590/s0103-97332004000500006

Cited by 18 publications

(8 citation statements)

References 14 publications

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“…This fact shows the importance of the choice of method for soil bulk density determination. For example, Pires et al (2003b) found problems of soil compaction during sampling by the VR method, a fact also mentioned by Grossman and Reinsch (2002). Another limitation of this method is related to the soil moisture at sampling, not recommended for too dry or too wet soils (Kiehl 1979).…”

Section: Resultsmentioning

confidence: 99%

Soil bulk density evaluation by conventional and nuclear methods

Timm¹,

Pires²,

Reichardt³

et al. 2005

Soil Res.

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Among the methods used to measure soil bulk density, the following have been prominent: paraffin sealed clod (PS), volumetric ring (VR), and the modern methods like gamma ray computed tomography (GCT) and the neutron/gamma surface gauge (SG). The objective of this work was to compare soil bulk density values obtained through these methods, with the aim of assisting researchers on the choice of the more appropriate method. For this, a 200-m spatial transect was chosen in an experimental area cultivated with coffee, belonging to ESALQ/USP, Piracicaba, SP, Brazil. The SG readings were first taken in the field and thereafter soil samples were collected at 8 different points, spaced at 25 m, for the other methods. The lowest values of soil bulk density were obtained for the SG method (average 1.468 g/cm 3 ) and the highest for the PS (average 1.685 g/cm 3 ), which was similar to the GCT method (average 1.684 g/cm 3 ). The average soil bulk density for the VR method, which has been used in soil science as a standard method, was 1.544 g/cm 3 . The Tukey test indicates that the PS and GCT methods do not differ significantly (P > 0.05). They do differ in comparison with VR and SG, which also do not differ among themselves.Additional keywords: soil bulk density, computed tomography method, surface gauge method, volumetric ring method, paraffin sealed clods method.

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Section: Resultsmentioning

confidence: 99%

Soil bulk density evaluation by conventional and nuclear methods

Timm¹,

Pires²,

Reichardt³

et al. 2005

Soil Res.

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“…More recently, research employing this technique for the study of soils have allowed researchers all over the world not only to investigate the physical properties of this heterogeneous medium (Pires et al, 2004(Pires et al, , 2005Papadopoulos et al, 2009;Tippkötter et al, 2009;Borges et al, 2012;Rab et al, 2014), but also to develop and evaluate the method applied to it (Oh and Lindquist, 1999;van Geet et al, 2003;Elliot and Heck, 2007a,b;Tarquis et al, 2009;Moreira et al, 2012;Tarquis et al, 2012). In this context, the technique has proven to be efficient for characterization of the soil pore system.…”

Section: Introductionmentioning

confidence: 99%

Three Dimensional Characterization of Soil Macroporosity by X-Ray Microtomography

Passoni¹,

Pires

Heck

et al. 2015

Rev. Bras. Ciênc. Solo

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analysis of the soil pore system represents an important way of characterizing soil structure. properties such as the shape and number of pores can be determined through soil pore evaluations. this study presents a three-dimensional (3d) characterization of the shape and number of pores of a sub-tropical soil. to do so, a second generation X-ray microtomograph equipped with a plain type detector was employed. a voltage of 120 kV and current of 80 ma was applied to the X-ray tube. the soil samples analyzed were collected at three different depths (0-10, 10-20, and 20-30 cm). the results obtained allowed qualitative (images) and quantitative (3d) analyses of the soil structure, revealing the potential of the microtomographic technique, as well as the study of differences in soil macroporosity at different depths. macroporosity was 5.14 % in the 0-10 cm layer, 5.10 % in the 10-20 cm layer, and 6.64 % in the 20-30 cm layer. the macroporosity of unclassified pores (UN) was 0.30 % (0-10 and 10-20 cm) and 0.40 % (20-30 cm), while equant pores (eQ) had values of 0.01 % at the three depths under analysis.Keywords: soil structure, pore size distribution, soil porosity, image analysis, soil microstructural components. RESUMO: CARACTERIZAÇÃO

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“…Figs. 4 and 5 show a clear heterogeneity of TU and the occurrence of larger values (dark areas) near the edges of the samples [34]. There is a density gradient for samples obtained with tensiometers and soil solution extractors, which can influence the soil water distribution along the porous cup due to changes in soil structure [35,36].…”

Section: Resultsmentioning

confidence: 99%