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Mathieu Lamandé

Effects of CT Number-Derived Matrix Density on Preferential Flow 1 and Transport in a Macroporous Agricultural Soil

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  • Sheela Katuwal, Denmark
  • Per Moldrup, Environmental Engineering Section, Dept. of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 57, DK-9000 Aalborg, Denmark, Denmark
  • Mathieu Lamandé
  • Markus Tuller, Denmark
  • Lis Wollesen de Jonge
Preferential flow and transport in structured soils can be intimately linked to numerous environmental problems. Surface-applied chemicals are susceptible to rapid transport in structural soil pores to deeper depths, thereby potentially contaminating valuable environmental resources and posing risks to public health. This study was focused on establishing links between the structural pore space and preferential transport using a combination of standard physical measurement methods for air and water permeabilities, breakthrough experiments, and X-ray Computed Tomography (CT) on large soil columns. Substantial structural heterogeneity that resulted in significant variations of flow and tracer transport was observed, despite the textural similarity of investigated samples. Quantification of macropore characteristics with X-ray CT was useful but not sufficient to explain the variability in air permeability, saturated hydraulic conductivity and solute transport. This was due to the limited CT scan resolution and large structural variability below this resolution. However, CTmatrix, a new parameter derived from the CT-number of the matrix excluding stones and large mostly air-filled macropores, was found to be useful for determining the magnitude of preferential flow under constant, near-saturated flow boundary conditions.
Original languageEnglish
JournalVadose Zone Journal
Volume14
Issue7
ISSN1539-1663
DOIs
Publication statusPublished - 2015

    Research areas

  • Preferential flow and transport, structured soils, X-ray computed tomography, CT number-derived matrix density

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