Abstract/Details

Soil surface-seal measurement using high-resolution X-ray computed tomography (HRCT)


2006 2006

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Abstract (summary)

Rainfall on bare soil breaks soil aggregates, detaching particles, plugging pores and decreasing porosity in the top few mm of soil. This reduces hydraulic conductivity and increases runoff through a process known as surface sealing. The objectives of this study are to measure saturated hydraulic conductivity (Ksat) of surface seals developed on bare Mexico silt loam (Aeric Vertic Epiaqualfs) during a simulated rainfall event, to evaluate the effect of anionic polyacrylamide (PAM) for maintaining high Ksat, and to evaluate models of sealing using total porosity, pore-size distribution collected with high-resolution X-ray computed tomography (HRCT). The study used a factorial design. Factors included rainfall duration (0-, 7.5-, 15-, 30-, and 60-min) at 55-mm hr-1 rainfall intensity, and an untreated soil or a soil amended with 20-kg ha-1 PAM. Application of PAM for various rainfall durations maintained from 20% to 41% higher Ksat than did untreated soil, for all times tested. Use of PAM produced different seal density (ρ) increased, and total porosity and pore-size decreased rapidly after a 15-min rainfall. HRCT-ρ data helped identify the best model selection for characterizing seal ρ profile. Although the cost is expensive, HRCT-image is a valuable tool to measure soil properties by analyzing soil thickness down to 0.015-mm. The study confirms that HRCT-analysis of soil allows accurate and direct measurements of seal effects on water flow and documents the usefulness of PAM for reducing surface sealing.

Indexing (details)


Subject
Hydrology;
Soil sciences;
Environmental science
Classification
0388: Hydrology
0481: Soil sciences
0768: Environmental science
Identifier / keyword
Health and environmental sciences; Earth sciences; Biological sciences
Title
Soil surface-seal measurement using high-resolution X-ray computed tomography (HRCT)
Author
Lee, Sang Soo
Number of pages
155
Publication year
2006
Degree date
2006
School code
0133
Source
MAI 46/02M, Masters Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780549264422
Advisor
Gantzer, Clark J.
University/institution
University of Missouri - Columbia
University location
United States -- Missouri
Degree
M.S.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
1448785
ProQuest document ID
305315869
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305315869
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