COMPARISON BETWEEN MODERN IRRIGATION SYSTEM DESIGNS

Abstract

Weather elements play an important role in plant life. They were measured to estimate evapotranspiration. The Penman model was used to determine potential ET in this research project due to the variety of field weather elements involved as well as recommendations made by many researchers. The average potential ET was considered to be as 3 and 2 mm of water per day for winter and 4 and 5.5 mm of water per day for summer in Kula, Maui, Hawaii and Shibin El-kom, Egypt, respectively. The irrigation experiments were conducted in Kula, Maui, Hawaii and Shibin El Korn, Egypt. A drip irrigation system with ten different amounts of water treatments was designed and installed to disperse water throughout onion and cabbage fields. The amount of water use ranged from 0.2ET to 2.0ET. Water applied, ET,~ corresponding to the maximum yield, Y~ was measured as the maximum amount of crop evapotranspiration, ET. These confirmed the crop ET. The results of irrigation experiments that were collected showed that the yield reduction occurred by both deficit and over-irrigation. This crop response was defined by model II. For the case when the yield was not changed by first portion over-irrigation {the top point was extended to a horizontal line for a while), the response curve can be considered as response model III. The shape of the crop response curve is a function of the given crop. The uniformity coefficient as well as the coefficient of variation can be used for both sprinkler and drip irrigation systems. When the system is designed for high uniformity (UC 2> 70%) the water distribution can be expressed as a normal distribution. Furthermore, it can be simplified to a straight line of water distribution