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1 Litwiller, K. E.; Tinsley, R. L.; Deweeb, H. H.; Ley, T. W. 1984. Infiltration studies on Egyptian vertisols. Cairo: Egypt Water Use and Management Project. ix, 66p. (EWUP technical report no.57)

Infiltration ; Soil water ; Water table ; Surface drainage ; Water distribution ; Water management / Egypt

(Location: IWMI-HQ Call no: 631.7.2 G232 LIT Record No: H037)

Twenty-one cylinder infiltration tests were conducted during irrigation of wheat on the shrinking/swelling vertisol soils of Kafr El-Sheikh, Egypt. Infiltration rates decreased rapidly from 720 mm/ hr for the first minute to 7.2 mm/hr at 2 hours elapsed time, with 1/3 of the tests showing soil sealing. In the majority of tests a well-defined two phase cumulative infiltration curve was determined. Significant correlations of antecedent soil moisture content in the 0-100 mm and 0-200 mm soil depth at the phase change, and average infiltration rate during the first phase were found. The first phase of infiltration was considered to represent flow of water through the soil macropores in the drier upper layer and water through the soil macropores. The second phase represented vertical flow into the wetter lower soil layers and filling of the finite storage space above the high water table. The analysis indicated a design application depth for wheat of not less than 120 mm for the first irrigation and 55 mm for subsequent irrigations under prevailing Abu Raya irrigation practices. Good water distribution across the field was facilitated by low long-term infiltration rates and high water table conditions. With the low second phase infiltration rates, water ponded in field depressions for prolonged periods could be detrimental to crops and requires provision for surface drainage. Precision land levelling would reduce this hazard.