Comparative study of the hydraulic characteristics of Moistube and SLECI irrigation systems and conventional drip irrigation

Abstract

Water scarcity associated with intense droughts due to climate change calls for improved irrigation techniques in arid zones. In this study, a series of tests was installed in the laboratory to define the discharge-pressure relationship and flow uniformity of the new Moistube and Self-regulating, Low Energy, Clay-based Irrigation (SLECI) systems in comparison with conventional drip irrigation. Moistube and SLECI are a new subsurface irrigation technology where the water emits at a slow rate depending on the applied pressure and soil water potential. There is currently limited information on the performance of these technologies with respect to discharge as a function of pressure or water quality. The aim of this study was to determine hydraulic characteristics of these systems under different operating pressures by determining water distribution homogeneity at variable laterals lengths. The results show that the Moistube system has very low tolerance to pressure variation and high heterogeneity of water distribution. The coefficient of variation stills in the acceptable range (<20%) and decreases with operating pressure.  The SLECI system is tolerant to pressure variations and characterized by a partially turbulent flow. Conventional self-regulating drippers are highly tolerant to pressure variation. The results obtained suggest that the length of laterals should be taken into account in the design of these systems to ensure homogeneous and uniform irrigation, generally not exceeding 40 m. The results of this study should help in the design, operation and maintenance of Moistube and SLECI systems.