Abstract
Vertisols cover a significant part of agriculturally important area of
semi-arid regions. Because of their swelling properties, their hydrology
is complicated with dominant preferential flow in their typical
desiccation cracks that work as conduits for both rapid infiltration and
for evaporation causing soil salinisation. The hydrology of vertisols
has been extensively studied and conceptually described recently, but
the transformation of this knowledge into mathematical models remains a
challenge. The presented model is based on dual-permeability idea by
Gerke and van Genuchten (1993) and divides the flow in the area into two
parts, one representing the matrix and the other the cracks. On top of
that, evaporation through the cracks is described by the sink/source
term in Richards equation describing the matrix. The input parameters of
the model are the hydraulic properties of the matrix, the depth of
cracks for evaporation, and precipitation and potential evaporation.
Fitting parameters in numerical solution of the model include the
hydraulic properties of cracks based on the knowledge of their width and
geometry. The model results are compared with the depth distribution of
chlorides in soil water. The most noteworthy outputs of the model are:
the percentage of water infiltrated and evaporated through the cracks
and the amount of water percolating to groundwater. In the future
studies, in addition to numerical implementations, there will be a need
to assess the soil hydraulic behaviour variations throughout the year.
This research was funded by the Charles University Grant Agency (GAUK
#1046217).
| Original language | English |
|---|---|
| Pages | 7742 |
| State | Published - 1 Apr 2018 |