HR: 1340h
AN: H53F-1500    [Abstracts]
TI: Characterization of Potential Preferential Pathways in Soil Columns by X-ray Tomography and Infiltration Experiments
AU: * Snehota, M
EM: michal.snehota@fsv.cvut.cz
AF: Dept. of Irrigation, Drainage and Landscape Eng., CTU in Prague, Thakurova 7, Prague, 16629, Czech Republic
AU: Sobotkova, M
EM: martina.sobotkova.1@fsv.cvut.cz
AF: Dept. of Irrigation, Drainage and Landscape Eng., CTU in Prague, Thakurova 7, Prague, 16629, Czech Republic
AU: Ray, C
EM: cray@hawaii.edu
AF: Water Resources Research Center, University of Hawaii, Holmes Hall 283, 2540 Dole St, Honolulu, HI 96822, United States
AU: Cislerova, M
EM: cislerova@fsv.cvut.cz
AF: Dept. of Irrigation, Drainage and Landscape Eng., CTU in Prague, Thakurova 7, Prague, 16629, Czech Republic
AB: Disturbances of soil structure, which originate from both biological and physical processes in soil often represent pathways of the preferential flow. Larger structures can be well identified by X-ray computed tomography (CT) of the soil. In this study the regions of high porosity, which can represent preferential pathways, were identified by thresholding of the CT images followed by modified morphological operation of erosion and dilation. Five undisturbed soil columns from Cambisol and Oxisol series from different locations have been studied. Volumes of high porosity regions were calculated for each threshold value and semivariograms were calculated for original images as well as for high porosity regions only. Data from CT were analyzed in connection with the flow dynamics as monitored on the same soil columns by experiments in laboratory. Experiments consisted of series of infiltration events done using modified tension infiltration disc placed on the top of the soil column. The bottom surface of soil column was supported by the perforated plate and was exposed to the atmospheric pressure. Cumulative outflow and the total mass of the soil core were recorded as well as pressure heads measured by tensiometers. Experiments revealed occurrence of the preferential flow for the soil from Cambisol series. For soil core from Oxisol series the preferential flow was less pronounced. These observations correspond with the results of CT images analysis, where soils from Cambisol series showed distinct networks of high porosity regions. This research has been supported by MSMT 1K05024.
DE: 1838 Infiltration
DE: 1865 Soils (0486)
DE: 1866 Soil moisture
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: 2007 Fall Meeting