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Comparison of Three Field Methods to Characterize Apparent Macropore Conductivity
Author(s) -
Timlin D. J.,
Ahuja L. R.,
Ankeny M. D.
Publication year - 1994
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1994.03615995005800020003x
Subject(s) - infiltrometer , macropore , hydraulic conductivity , infiltration (hvac) , saturation (graph theory) , soil science , soil water , geology , mineralogy , chemistry , materials science , composite material , mesoporous material , biochemistry , mathematics , combinatorics , catalysis
The objective of this study was to investigate some field‐oriented methods designed to characterize the flow rates of both the soil matrix and macropores near saturation. An apparent macropore conductivity was obtained by the difference between saturated and unsaturated hydraulic conductivities at −0.6 kPa of soil water pressure. Saturated conductivities were measured in double‐ring infiltrometers with tensiometers. Soil matrix conductivities were calculated from measurements of soil water pressures and drainage rate during redistribution and were also measured with a thin sand‐cement crust. Another set of data for saturated and unsaturated conductivities was obtained from unconfined ponded measurements in 76.2‐mm‐diam. rings and a tension infiltrometer. Unsaturated conductivities and calculated apparent macropore conductivities from the crust and redistribution methods were comparable. Unsaturated conductivities and apparent macropore conductivities from the tension infiltrometer and unconfined ponded measurements were greater than those from the infiltration‐redistribution method. We concluded that apparent macropore conductivity for the profile can be characterized by using ponded infiltration rates and matrix conductivities near saturation determined from redistribution data. This method accounts for the continuity of the macropore flow system in subsurface layers and involves a larger area for macropore infiltration measurement.