الفهرس 
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Abstract
The aim of this research is developing a model for designa simple low head bubbler irrigation system for intensivecrops.Laboratory hydraulic calibration experiments of bubbler tube and lateral design. Then, followed by evaluation and comparingthe water use efficiency (WUE) and soil moisture content of lateral length (Lℓ) 18m andtwo bubbler tube diameters (ID) 8.8 and 13.8mm at twice interval distance (Is) with flood and drip irrigation systems.The evaluation and comparing experiment was obtained by field experiment through two season of corn crop with water saving treatments.
The calibrationunder 1 to 13KPa effective pressures for lateral length 6m and diameter 61.8mm and twobubblers diameters of 8.8 and 13.8mm appeared that thedischarge exponent (x) and coefficient of manufacturing variation (Cv) were (0.3 and 0.4 which classified as partially turbulent) and (0.03 to 0.09 and 0.07 to 0.15 which classified between excellent to poor),respectively.
The designed lateral performance was calibrating for two bubbler ID of 8.8 and 13.8mmattwice Is of 2.0 and 4.0munderoperating pressure (Po) of 5.0, 7.5 and 10.0kPa. The results appeared that the effect of IDon its discharge and application uniformity was great, followed by PoandIs.Where, the effect of increase ID,Po and Is on average range of (theoretical and measured) discharge increasing percentage as follow (19.0 to 32.0% and 19.0 to 31.0%), (13.6 to 22.8% and 3.4 to 17.2%), (0.56 to 5.33% and 1.24 to 9.13%), respectively. The uniformity classification of this lateral length was excellent with all treatments for theoreticaldesign, whereas it was fluctuated between good to excellent for measured data.
WUE comparison with other irrigation systems under soil surface covering and fertilizer types & levels,reach (0.92 and 0.97),(0.89 and 0.93) and(0.72 and 0.8287kg/m³)with drip, low head bubbler and flood irrigation system respectively. The soil moisture content with fertilizer treatments was bubbler came at the first followed by dripand then flood irrigation systems. The economic study of tested bubbler Is 2.0 and 4.0m appeared that the dividing ratio of total cost over total return (LE/fed/season) was (1.30 and 1.32) and (1.38 and 1.34) for ID 8.8 and 13.8mm, respectively.
The study concluded that this design model is good and by comparing it with other irrigation systems, showed high efficiency. So software program was structured to design a simple low head bubbler irrigation system.