Effect of Furrow Irrigation Systems and Irrigation Levels on Maize Agronomy and Water Use Efficiency in Arba Minch, Southern, Ethiopia

Abstract Improved irrigation water management is the main strategy to improve water use efficiency in areas where water resources are limited. Optimizing scarce water by selecting suitable furrow irrigation systems in arid and semi-arid parts of Ethiopia is rarely practiced. A field experiment was carried out to evaluate the effect of conventional, alternate, and fixed furrow irrigation systems with three levels of irrigation (100%ETc, 75%ETc, and 50%ETc) on maize agronomy and water use efficiency in Arba Minch, Southern, Ethiopia. The experimental study had nine treatments under a randomized complete block design with three replications. Furrow irrigation system and deficit irrigation levels had a significant impact (P < 0.01) on maize agronomy (plant height, days to tassel and silk, cob length and diameter, and aboveground biomass). The maximum grain yield of 7.99 ton ha-1 obtained under a conventional furrow irrigation system at 100%ETc was significantly superior as compared to other irrigation treatments and the minimum grain yield of 4.24 ton ha-1 obtained under a fixed furrow irrigation system at 50%ETc was significantly inferior as compared to other treatments. The maximum values of crop, field, and expense water use efficiencies were 2.49, 2.80, and 1.72 kg m-3 under conventional furrow irrigation at 50%ETc, respectively. The minimum values of crop, field, and expense water use efficiencies were 1.47, 1.28, and 1.05 Kg m-3 under a fixed furrow irrigation system at 100%ETc, respectively. Furrow irrigation systems and irrigation levels had a significant impact (P 0.01) on water use efficiency and grain yield. Conventional furrow irrigation system at 50%ETc can increase 0.64 ha net additional irrigable land pre each hectare compared to control (conventional furrow irrigation system at 100%ETc). Water saving up to 50%ETc in conventional furrow irrigation can solve the water shortage problem by improving water use efficiency with insignificant yield reduction.