Abstract
Drip irrigation is important in rationing the use of irrigation water, especially in arid and semi-arid regions that suffer from a severe shortage of water resources. To estimate the volume of the wetted soil under drip irrigation, twelve laboratory experiments were conducted to track the advancement of the wetting front during certain times for the wetting phase and the moisture redistribution phase as a result of adding water from two linear drip sources. Three spacings between the emitters (30, 40, 50) cm were considered for a layered soil consisting of two soil textures: one with clay over sandy loam, and the other with sandy loam over clay. Two rates of discharge (0.956 and 1.515 cm3/min/cm) were considered. The data were represented by empirical relationships to estimate the wetting pattern in the horizontal and vertical directions and in the middle of the spacing between the two emitters, with a determination coefficient of 0.96, 0.98, and 0.97, respectively. It was observed that the wetting pattern increases with a decrease in the interval between the drippers, and that this increase is regular along the wet perimeter, and this increase is greater in the vertical direction than in the horizontal direction, and for both soil profiles. In addition, an increase in water application let to increase the vertical progression, as it is greater in the case of soil profile (sandy loam over clay), while the horizontal progression is clear for the soil profile (clay over sandy loam).
