Enhancing water use efficiency is essential in irrigated agricultural due to declining water resources, increasing population, growing water needs, and greater competition among water users. If properly designed and managed, with good operation and maintenance, center-pivot irrigation system can have high water application efficiency. One of the design factors for a center-pivot irrigation system is the hydraulic loss in the lateral pipe. In this study, an analytical relationship is presented as a series for calculating the hydraulic loss in the lateral pipe of a center-pivot irrigation system. Given the difficulty and complexity of using a mathematical series, the, the equation presented in this study and the equation developed by Anwar turn out to be general and asymptotic relations. The final relationships have 0.6% and 0.4% errors, respectively, relative to the series relationships. Due to the high accuracy and ease use of the asymptotic relationship presented to calculate the hydraulic loss in the lateral pipe, it is recommended for use in designing center-pivot irrigation systems.
