INTRODUCTION
Understanding of irrigation-induced infiltration and characteristics of
soil water movement are fundamental to efficient management of water
resources, especially for those of arid and semi-arid regions where
water is scarce and crop production is critical for economic
development. It is also the basis of consideration in the design,
evaluation, and management of an irrigation system (Zerihun et al.,
1996; Oyonarte et al., 2002). Infiltration characteristics, particularly
infiltrability of cropland directly affect irrigation scheduling and
water use efficiency; hence the performance of an irrigation system is
strongly influenced by infiltration.
Nevertheless, these processes are much more complex than those in
saturated zones, since they are involved with multiphase flow processes
such as gravity- and capillary-driven moisture flow (Doughty, 1999).
Despite the complexity of soil water infiltration, its impacting factors
can be aggregated into two main aspects, namely soil physical properties
and the time and amount of water applied (Shainberg and Singer, 1985;
Shainberg et al., 1991), the latter of which actually is associated with
irrigation methods and scheduling.
Numerical simulation is an ideal tool to investigate the processes of
irrigation induced water infiltration and to assess the performance of
various irrigation schedules, by looking into the dynamics of wetting
front and the resulting distribution of SWC. The present study focuses
on simulating infiltration physics and analyzing its potential
influencing factors, to shed light on the design of irrigation systems
that improve the efficiency of water use. This is of significance
especially for those areas where the sustainability of the irrigated
agriculture is at serious risk.