Infiltration, Redistribution, and Subsequent Evaporation of Water from Soil as Affected by Wetting Rate and Hysteresis1
- E. Bresler,
- W. D. Kemper and
- R. J. Hanks2
Soil columns were wetted at three different rates which caused unequal water content profiles during infiltration. Water content profiles during infiltration, redistribution, and evaporation were observed experimentally and computed using a numerical solution of the isothermal flow equation. Each wetting rate resulted in a different drying water retention curve. The hysteresis in soil water content-water suction relationships had a larger influence as the wetting rate increased. Hysteresis effects tend to keep the water content higher and the zone of wetting shallower during the redistribution stage when rates of wetting are faster. Higher water content and lower wetting depth at any redistribution time caused subsequent evaporation to be greater. Evaporation was directly related to the previous wetting rate, either when the soil was subjected to evaporation immediately following infiltration or when subjected to evaporation after redistribution for 4 days. The differences in evaporation between the three wetting treatments were significant at the 99% probability level. Allowing time for redistribution decreased evaporation compared to evaporation and redistribution occurring simultaneously. The effects of wetting rates and hysteresis on water content profiles and evaporation were similar in the experimental and computed results.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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