Macropores generated during shrinkage in two paddy soils using X-ray micro-computed tomography

Bottinelli, Nicolas; Zhou, Hu; Boivin, Pascal; Zhang, Z. B.; Jouquet, Pascal; Hartmann, Christian; Peng, Xinhua

doi:10.1016/j.geoderma.2015.11.011

Cited by 57 publications

(30 citation statements)

References 32 publications

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“…The degree of anisotropy strongly reflects the orientation of the elements inside a determined volume (Odgaard, 1997); thus, it influences the flux characteristics in a porous medium (Hernández Zubeldia et al, 2015). Bottinelli et al (2016) demonstrated the stability of the degree of anisotropy in the formation of macropores during shrinkage in rice-cultivated soils.…”

Section: Introductionmentioning

confidence: 93%

Quantifying physical and structural soil properties using X-ray microtomography

2018

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One of the current challenges in the study of recovering soil architecture is physically evaluating the internal soil structure in unconventional ways. The elaboration of consistent methods and physical parameters has become necessary for soil structural analysis. The aim of this study is to analyze the soil structures of two groups of recovering tropical soils and to simulate three-dimensional water movement pathways using unconventional methods and physical soil parameters. The following results were obtained from the analysis: 1) the S index was used as an indicator to effectively quantify the degree of management; 2) Qualisolo software was used to obtain the soil water retention curve (SWRC) of each management type; 3) the degree of anisotropy of the solid structure reflected the soil network; 4) the Euler-Poincaré number reflected the connectivity of the soil pores for each management type; 5) the Shannon entropy indicated the degree of randomness of the soil; and 6) the results of the Arya and Paris model and the simulations of water movement pathways are similar. In conclusion, the obtained results reflect the internal soil structures and their corresponding characteristics. Thus, the results can be used to predict the influence of soil architecture on the movement of water in the soil.

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Section: Introductionmentioning

confidence: 93%

Quantifying physical and structural soil properties using X-ray microtomography

2018

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“…Yoshida and Hallett ( 2008 ) found drying of paddy soils to −50 kPa water potential increased mechanical strength considerably, and that this strength did not decrease with subsequent wetting. Macropores may form as cracks and pre-existing pores that extend (Bottinelli et al 2016 ), creating connected pore systems favourable to rapid root growth. Under AWD, roots may therefore experience greater mechanical impedance from the soil matrix, but take greater advantage of newly formed pore networks.…”

Section: Introductionmentioning

confidence: 99%

Interaction between contrasting rice genotypes and soil physical conditions induced by hydraulic stresses typical of alternate wetting and drying irrigation of soil

et al. 2018

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Background and aimsAlternate wetting and drying (AWD) saves water in paddy rice production but could influence soil physical conditions and root growth. This study investigated the interaction between contrasting rice genotypes, soil structure and mechanical impedance influenced by hydraulic stresses typical of AWD.MethodsContrasting rice genotypes, IR64 and deeper-rooting Black Gora were grown in various soil conditions for 2 weeks. For the AWD treatments the soil was either maintained in a puddled state, equilibrated to −5 kPa (WET), or dried to −50 kPa and then rewetted at the water potential of −5 kPa (DRY-WET). There was an additional manipulated macropore structure treatment, i.e. the soil was broken into aggregates, packed into cores and equilibrated to −5 kPa (REPACKED). A flooded treatment (puddled soil remained flooded until harvest) was set as a control (FLOODED). Soil bulk density, penetration resistance and X-ray Computed Tomography (CT) derived macropore structure were measured. Total root length, root surface area, root volume, average diameter, and tip number were determined by WinRhizo.ResultsAWD induced formation of macropores and slightly increased soil mechanical impedance. The total root length of the AWD and REPACKED treatments were 1.7–2.2 and 3.5–4.2 times greater than that of the FLOODED treatment. There was no significant difference between WET and DRY-WET treatments. The differences between genotypes were minimal.ConclusionsAWD influenced soil physical properties and some root characteristics of rice seedlings, but drying soil initially to −50 kPa versus −5 kPa had no impact. Macropores formed intentionally from repacking caused a large change in root characteristics.

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“…pore connectivity, pore shape and pore volume). Some studies have scanned soil cores from 3 to 20 cm at a 15-500-μm resolution in order to visualize and quantify macropore characteristics and thus predict soil hydrogeochemical functions (Bottinelli et al, 2016;Katuwal, Arthur, Tuller, Moldrup, & de Jonge, 2015).…”

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confidence: 99%

Reconfiguration of macropore networks in a silty loam soil following biochar addition identified by X‐ray microtomography and network analyses

2019

European J Soil Science

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Biochars are widely applied to improve soil pore structures. However, the quantitative effects of biochars on soil macropore networks still remain unclear. In this study, the effects and possible mechanism of biochar application on soil macropore networks were investigated quantitatively by industrial X‐ray microtomography (CT), a pore network model and network analyses. Soil cores of 5 cm in diameter and 10 cm in height were collected from a paddy soil (Typic Haplustalf) without biochar application (CK), and amended with rice straw biochar (RSB), corn straw biochar (CSB) and bamboo biochar (BB) at a rate of 25 Mg ha−1 (w/w). Results revealed that the total and connected macroporosity of the biochar‐amended soil was reduced significantly compared with CK, whereas the reverse was true for the isolated porosity. The three types of biochars exhibited different effects on macropores of the soil, depending on their size and shape. The pore network model and network analyses showed that the physical and topological structures of macropore networks in biochar‐amended soil were clearly reconfigured. The accessibility of these macropore networks was markedly reduced. Our results indicated that the incorporation of biochar did not necessarily increase the soil's macroporosity. The combination of pore network model and network analyses was effective for quantifying key properties of soil macropore networks affected by the incorporation of biochar. The changes in these properties may be used to evaluate the effects of biochar on water, air and nutrient transport. Highlights Effect of biochars on the soil macropore structure was studied by industrial CT. Macropore network structure was quantified by a pore network model and network analyses. Biochar incorporation markedly changed the accessibility of the soil macropore network. The macropore network of soil can be reconfigured following biochar addition.

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Macropores generated during shrinkage in two paddy soils using X-ray micro-computed tomography

Cited by 57 publications

References 32 publications

Quantifying physical and structural soil properties using X-ray microtomography

Quantifying physical and structural soil properties using X-ray microtomography

Interaction between contrasting rice genotypes and soil physical conditions induced by hydraulic stresses typical of alternate wetting and drying irrigation of soil

Reconfiguration of macropore networks in a silty loam soil following biochar addition identified by X‐ray microtomography and network analyses

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