Soil aggregate geometry: Measurements and morphology

Martínez, Fernando San José; Muñoz, Florentino Jiménez; Monreal, Francisco Javier Caniego; Kravchenko, Alexandra; Wang, W.

doi:10.1016/j.geoderma.2014.08.003

Cited by 20 publications

(13 citation statements)

References 43 publications

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“…Aggregate stability is an important factor in assessing soil physical quality and maintaining long‐term crop productivity (Gelaw et al , ; San José Martínez et al , ). Improved soil aggregate stability may benefit root penetration, water transportation, gas diffusion, and seedling emergence (Hartley et al , ).…”

Section: Resultsmentioning

confidence: 99%

Vermicompost and Gypsum Amendments Improve Aggregate Formation in Bauxite Residue

et al. 2017

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Improving aggregate formation and stability of bauxite residue is essential for the development of a soil on the residue. Effects of gypsum and vermicompost on related chemical and physical conditions of bauxite residue were studied in a laboratory incubation experiment. The addition of gypsum at 2% and 4% w/w reduced pH and exchangeable sodium percentage while increasing exchangeable calcium content. The addition of vermicompost reduced bulk density while significantly increasing porosity and total organic carbon. Vermicompost had a positive effect on the formation and stabilization of water‐stable aggregates in the residue, while gypsum was more beneficial to silt‐sized microaggregate flocculation. Amendments also enhanced the erosion resistance of bauxite residue. Furthermore, wet sieving using the modified Le Bissonnais' method revealed that in comparison with differential clay swelling and mechanical breakdown, slaking was the major disaggregation mechanism of residue aggregates. The combination of gypsum and vermicompost converted the residue from a sheet‐like structure to a granular macroaggregated structure while converting microaggregates from a grain to a granular or prismatic structure. The findings of this work suggest that application of gypsum and vermicompost to bauxite residue may directly influence aggregate size distribution and its micromorphology, resulting in the improvement of both aggregate stability and structure. Copyright © 2017 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 99%

Vermicompost and Gypsum Amendments Improve Aggregate Formation in Bauxite Residue

et al. 2017

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“…Это означает, что описанный метод получения морфометрических параметров срезов агрегатов устойчив к возможному влиянию личности эксперта, выполняющего исследование (отсутствует субъективная погрешность). Сходные результаты получены в различных исследованиях при прямом измерении площади объектов на изображении с использованием непосредственно инструмента Magnetic Lasso программы Adobe Photoshop Wang et al, 2015). Однако нужно отметить, что при исследовании морфометрии агрегатов недостаточно только информации об их площади, а сложные расчеты в программе Adobe Photoshop выполнить нельзя.…”

Section: результаты и обсуждениеunclassified

Comparison of digital image analysis methods for morphometric characterization of soil aggregates in thin sections

Плотникова

Romanis

Kust

2020

DSB

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The purpose of this study was to investigate the applicability of semiautomatic segmentation methods for obtaining and evaluating morphometric parameters of soil aggregates in artificially prepared loose samples in soil thin sections. The object of the research is typical arable Chernozem. The aggregates were separated by wet sieving method from loose sample of upper 10 cm of the plowing horizon after erosion by a model shallow water flow on a large erosion tray. The aggregates, loosely scattered on the glass and fixed with polyester resin, were used to produce the thin sections. Images of the thin sections were taken under a polarizing microscope and then were processed using two methods compared: Adobe Photoshop + CTan and Thixomet Pro. Data on morphometric parameters of aggregates were obtained: the shape factor, the degree of roundness and the coefficient of aggregate surface roughness. The convergence of the results obtained using Photoshop + CTan by three researchers was evaluated by comparing samples using the Student's test and the Mann-Whitney test. The convergence of the averaged results obtained using Photoshop + CTan and the results obtained using Thixomet Pro was evaluated using the Mann - Whitney test. No significant differences were found between the parameters of the same aggregates obtained using a combination of Adobe Photoshop and CTan programs by different researchers. No significant differences were found between the parameters of the same aggregates obtained by the compared methods. So, one can conclude that the reliability of determining the morphometric parameters of soil aggregates using Thixomet Pro is comparable to the reliability of results when working with images of sectionsin CTan after binarization in Adobe Photoshop. The method of obtaining data on morphometric parameters of soil aggregates using Thixomet Pro completely eliminates the possibility of subjective error, shows a high degree of automation, reproducibility and reliability of the results obtained, and is faster.

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“…One possible explanation for the increased number of significant correlations between AE-metrics and PNMs in the smallest VoI and PNA with the smallest pores is: As aggregate size decreased, large biopores, with smooth, potentially hydrophobic surfaces [88], were increasingly destroyed. This lead to redistributed (i.e., more easily accessible) electron sources [15] and the generation of rough pore surfaces [70,89,90]. Rough pore surfaces have been shown to collect small, yet significant, pools of water [91], provide more attachment points and habitable niches for microbes [62,92,93], along with increased diffusion of nutrients in the pore water [94].…”

Section: The Explanatory Power Of Pnms Is Greatest For a Small Soil Vmentioning

confidence: 99%

The Ability of Soil Pore Network Metrics to Predict Redox Dynamics Is Scale Dependent

et al. 2018

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Variations in microbial community structure and metabolic efficiency are governed in part by oxygen availability, which is a function of water content, diffusion distance, and oxygen demand; for this reason, the volume, connectivity, and geometry of soil pores may exert primary controls on spatial metabolic diversity in soil. Here, we combine quantitative pore network metrics derived from X-ray computed tomography (XCT) with measurements of electromotive potentials to assess how the metabolic status of soil depends on variations of the overall pore network architecture. Contrasting pore network architectures were generated using a Mollisol—A horizon, and compared to intact control samples from the same soil. Mesocosms from each structural treatment were instrumented with Pt-electrodes to record available energy dynamics during a regimen of varying moisture conditions. We found that volume-based XCT-metrics were more frequently correlated with metrics describing changes in available energy than medial-axis XCT-metrics. An abundance of significant correlations between pore network metrics and available energy parameters was not only a function of pore architecture, but also of the dimensions of the sub-sample chosen for XCT analysis. Pore network metrics had the greatest power to statistically explain changes in available energy in the smallest volumes analyzed. Our work underscores the importance of scale in observations of natural systems.

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Soil aggregate geometry: Measurements and morphology

Cited by 20 publications

References 43 publications

Vermicompost and Gypsum Amendments Improve Aggregate Formation in Bauxite Residue

Vermicompost and Gypsum Amendments Improve Aggregate Formation in Bauxite Residue

Comparison of digital image analysis methods for morphometric characterization of soil aggregates in thin sections

The Ability of Soil Pore Network Metrics to Predict Redox Dynamics Is Scale Dependent

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