Influence of Hysteresis on Moisture Flow in an Undisturbed Soil Monolith1
- F. Beese and
- R. R. van der Ploeg2
The moisture dynamics of an undisturbed soil monolith were studied during a lysimeter experiment. Daily measurements were made of the soil suction at 10 depths. Also daily measured were the precipitation, the seepage, and the evaporation from the monolith during a 3-year period. For selected periods, a drying (desorption) curve and a wetting (sorption) curve of the soil moisture characteristic were determined from field data. Also the capillary conductivity was determined with use of daily monolith observations. With use of these hydraulic functions, the unsaturated soil moisture flow equation was solved numerically for one-dimensional vertical flow. In order to determine the effect of hysteresis on the suction distribution in the monolith, calculations were performed either with the desorption curve or with the sorption curve without scanning between these curves. Neither of the two curves leads to complete agreement between observed and calculated soil suction values; the desorption curve usually gives too high values, the sorption curve too low values.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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