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| Titel |
Evaluation of four models for predicting water retention curves of water repellent soils using parameters from wattable samples |
| VerfasserIn |
Hui Liu, Jörg Bachmann, Tusheng Ren |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250039767
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| Zusammenfassung |
| Soil water retention curve (SWRC) models are useful for studying hydrological
processes in wettable and water repellent soils. However, SWRC measurement is
time-consuming. For quantification of water movement in water repellent soils, it is
necessary to develop a general SWRC model based on hydrophilic SWRC data
and the independently determined degree of water repellency. In this study, we
investigated four hydrophobic SWRC models based on the van Genuchten equation using
water retention data (desorption) of wettable and water repellent sand, loam, and
silt loam. Sum of squared errors (SSE), root of mean squared errors (RMSE), and
Akaike information criterion (AIC) are applied to compare the model predictions
against measurements. The four models are: (1) vG-4, van Genuchten equation
with four fitting parameters (θs, θr, n and α) from hydrophobic soil; (2) vG-1, van
Genuchten equation with one fitted parameter (αobic) and three known fixed parameters
(θs, θr, and n) from the corresponding hydrophilic soil sample; (3) vG-αsingle,
modified van Genuchten equation by adjusting the known parameter αilic from
hydrophilic samplewith the initial air-dried hydrophobic soil contact angle and the
three known fixed parameters (θs, θr, and n) obtained from hydrophilic samples;
and (4) vG-αmult, modified van Genuchten equation by adjusting the hydrophilic
parameters αilicwith soil contact angles from hydrophobic samples measured under
different water contents, and the three known fixed parameters (θs, θr, and n) of
hydrophilic soils. Although relative lower SSE, RMSE and AIC values are found for the
vG-4 model and the vG-αmultmodel, the vG-αmult model is recommended due to
its capability of predicting the hydrophobic SWRC by using the van Genuchten
parameters from hydrophilic soil samples along with easily measured contact angles. |
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