Field experiment was conducted to evaluate infiltration rate
using two sprinkler application rates in soils with different gypsum contents. soil samples with 60.0 (G1), 137.6 (G2), 275.2
(G3), 314.2 (G4) and 486.0 (G5) g kg−1 gypsum content were prepared by mixing materials from surface soil layer (0–0.13 m deep)
with low gypsum content (60.0 g kg−1) and sub-surface soil layer
(0.13–0.72 m deep) with high gypsum content (860.0 g kg−1) from
the experimental station of Tikrit University. The soil gypsum content was determined for the prepared soil samples by the method
proposed by Al-Zubaidy et al. (1981). Prepared soil samples were
packed into metal boxes with dimensions of 2.00 m long, 1.00 m
wide and 0.50 m deep. Many small holes were drilled into the bottom of each box to allow infiltrated water to drain freely and filter
cloth was placed over the holes to prevent soil loss and any blocking
of the small holes. The soils were air dried, sieved and uniformly
packed by a wooden hammer into the metal boxes to a density of
1.35 Mg m−3 until each box was full and the soil surface was made
as smooth as practicable to eliminate surface storage. Each soil box
was placed in the field on a ramp with a 0% slope.