Research article - Peer-reviewed, 2021
Approaches to delineate aggregates in intact soil using X-ray imaging
Koestel, John; Fukumasu, Jumpei; Garland, Gina; Larsbo, Mats; Svensson, David NimbladAbstract
Soil structure refers to the spatial arrangement of primary soil particles and pores, and is known to influence a variety of soil functions including carbon sequestration and water holding capacity. At present, research in this field is often divided, focusing either on pores where pore networks are investigated in undisturbed soil or on solids where isolated soil aggregates are commonly studied. The choice of approach depends on the needs and traditions in different disciplines of soil science. While there is much debate regarding how well these viewpoints relate to each other, there have been only marginal research efforts undertaken to compare them quantitatively. In this study, we presented and evaluated methods to identify 3-D subunits in X-ray images of eight undisturbed soil samples that we interpreted as macroaggregates, and compared these to to results from drop-shatter tests. Here, we exploited the cohesive forces of water that induces shrinkage cracks under drying. Despite promising trends, comparisons between image and drop-shatter test derived aggregate properties remained inconclusive. Nevertheless, our results encourage further investigations on larger sample sets and different observation scales. The here presented and discussed aggregate delineation methods illustrate an approach to harmonize soil structure characterization in terms of both pore-networks and soil aggregation. For example, respective extended approaches may be developed to evaluate the locations of microaggregates within macroaggregates.Keywords
Soil structure; Soil aggregate; X-ray imaging; Pore network; Morphology; Dropshatter testPublished in
Geoderma2021, volume: 402, article number: 115360
Publisher: ELSEVIER
Authors' information
Koestel, John (Koestel, Johannes)
Swedish University of Agricultural Sciences, Department of Soil and Environment
Koestel, John (Koestel, Johannes)
Agroscope
Swedish University of Agricultural Sciences, Department of Soil and Environment
Garland, Gina
Swiss Federal Research Station Agroscope
Swedish University of Agricultural Sciences, Department of Soil and Environment
Swedish University of Agricultural Sciences, Department of Soil and Environment
UKÄ Subject classification
Soil Science
Publication Identifiers
DOI: https://doi.org/10.1016/j.geoderma.2021.115360
URI (permanent link to this page)
https://res.slu.se/id/publ/113475