TY - JOUR

T1 - Three-dimensional quantification of intra-aggregate pore-space features using synchrotron-radiation-based microtomography

AU - Peth, S.

AU - Horn, R.

AU - Beckmann, F.

AU - Donath, T.

AU - Fischer, J.

AU - Smucker, A. J.M.

PY - 2008/7

Y1 - 2008/7

N2 - Pore network geometries of intra-aggregate pore spaces are of great importance for water and ion flux rates controlling C sequestration and bioremediation. Advances in non-invasive three-dimensional imaging techniques such as synchrotron-radiation-based x-ray microtomography (SR-μCT), offer excellent opportunities to study the interrelationships between pore network geometry and physical processes at spatial resolutions of a few micrometers. In this paper we present quantitative three-dimensional pore-space geometry analyses of small scale (∼5 mm across) soil aggregates from different soil management systems (conventionally tilled vs. grassland). Reconstructed three-dimensional microtomography images at approximate isotropic voxel resolutions between 3.2 and 5.4 μm were analyzed for pore-space morphologies using a suite of image processing algorithms associated with the software published by Lindquist et al. Among the features quantified were pore-size distributions (PSDs), throat-area distributions, effective throat/pore radii ratios as well as frequency distributions of pore channel lengths, widths, and flow path tortuosities. We observed differences in storage and transport relevant pore-space morphological features between the two aggregates. Nodal pore volumes and throat surface areas were significantly smaller for the conventionally tilled (Conv. T.) aggregate (mode ≈ 7.9 × 10 -7 mm3/≈ 63 μm2) than for the grassland aggregate (mode ≈ 5.0 × 10-6 mm3/≈ 400 μm2), respectively. Path lengths were shorter for the Conv. T. aggregate (maximum lengths < 200 μm) compared with the grassland aggregate (maximum lengths > 600 μm). In summary, the soil aggregate from the Conv. T site showed more gas and water transport limiting micromorphological features compared with the aggregate from the grassland management system.

AB - Pore network geometries of intra-aggregate pore spaces are of great importance for water and ion flux rates controlling C sequestration and bioremediation. Advances in non-invasive three-dimensional imaging techniques such as synchrotron-radiation-based x-ray microtomography (SR-μCT), offer excellent opportunities to study the interrelationships between pore network geometry and physical processes at spatial resolutions of a few micrometers. In this paper we present quantitative three-dimensional pore-space geometry analyses of small scale (∼5 mm across) soil aggregates from different soil management systems (conventionally tilled vs. grassland). Reconstructed three-dimensional microtomography images at approximate isotropic voxel resolutions between 3.2 and 5.4 μm were analyzed for pore-space morphologies using a suite of image processing algorithms associated with the software published by Lindquist et al. Among the features quantified were pore-size distributions (PSDs), throat-area distributions, effective throat/pore radii ratios as well as frequency distributions of pore channel lengths, widths, and flow path tortuosities. We observed differences in storage and transport relevant pore-space morphological features between the two aggregates. Nodal pore volumes and throat surface areas were significantly smaller for the conventionally tilled (Conv. T.) aggregate (mode ≈ 7.9 × 10 -7 mm3/≈ 63 μm2) than for the grassland aggregate (mode ≈ 5.0 × 10-6 mm3/≈ 400 μm2), respectively. Path lengths were shorter for the Conv. T. aggregate (maximum lengths < 200 μm) compared with the grassland aggregate (maximum lengths > 600 μm). In summary, the soil aggregate from the Conv. T site showed more gas and water transport limiting micromorphological features compared with the aggregate from the grassland management system.

UR - http://www.scopus.com/inward/record.url?scp=47249142399&partnerID=8YFLogxK

U2 - 10.2136/sssaj2007.0130

DO - 10.2136/sssaj2007.0130

M3 - Article

AN - SCOPUS:47249142399

VL - 72

SP - 897

EP - 907

JO - Soil Science Society of America Journal

JF - Soil Science Society of America Journal

SN - 0361-5995

IS - 4

ER -