Effect of irrigation method and spacing on yield and water productivity of maize (Zea mays L.) in Lake Tana Basin, Ethiopia

Abstract Poor water allocation, land leveling, and suboptimal irrigation practices are key challenges affecting irrigated agriculture in Ethiopia, particularly in regions with scarce water resources. Irrigation methods play a critical role in improving water use efficiency and crop production. In Lake Tana Basin, Ethiopia, Maize is predominantly cultivated using a conventional irrigation method combined with varying row spacing, which results in low grain yield and poor water efficiency. Consequently, this study aimed to evaluate the effects of irrigation methods (conventional and bed) and plant spacing (55, 65 and 75 cm) on maize yield, applied water and water productivity. Agronomic traits, applied water, and water productivity were measured and analysed by a two-way analysis of variance (ANOVA). The result revealed that bed irrigation (BI) with 55 cm spacing significantly achieved 7807.3 kg ha−1 grain yield (6.4% increase), saved 843.61 m3 ha−1 of water (18.6% reduction), and improved water productivity by 1.72 kg m−3 (26.2% increase) compared to the same row spacing. Highest water productivity (2.30 kg m⁻3) was recorded in the bed irrigation at 75 cm spacing, and the highest saved water (36.8% reduction) was observed with 65 cm spacing compared to the conventional method. These results highlight the potential of bed irrigation as a sustainable strategy for improving agricultural productivity in water-scarce regions.