Effect of Drip Lateral Spacing and Water Levels on Yield and Water Use Efficiency of Onion ( allium cepa l. ) Under Awash Melkassa Climatic Condition

Abstract

Water being scarce resources, irrigation water is the most limiting factor for vegetable production in the central rift valley of Ethiopia. Drip irrigation technique together with deficit irrigation application improves crop yield and water use efficiency. Hence, the objective of this study was to enhance onion production and WUE through the application of drip irrigation technology and deficit irrigation application. Field experiment was conducted at Melkassa agricultural research center during the cool cropping season of 2019/2020 to investigate the effects of drip lateral spacing and irrigation levels on onion yield, water use efficiency and net return. Two levels of drip lateral spacing viz., lateral placed in every row and between two rows, and three levels of deficit irrigation viz., 80% ETc, 70% ETc and 55% ETc, and one-full irrigation (100% ETc). The treatments were arranged in split plot with three replications. Data were analyzed using statistical package appropriate to split plot with the help of SAS software. The result showed that onion yield, yield parameters and water use efficiency was affected by the effects of drip lateral spacing and irrigation water levels but not affected by their interaction effect. Onion bulb yield decreased with increased levels of water deficit. In contrast, both water use efficiency and irrigation water use efficiency increased with increase in water deficit level. Maximum onion bulb yield of 41.43 t ha-1 were obtained from lateral spacing in every row and full irrigation application level of 100% ETc and has no a significant difference with every row lateral spacing, and 85% and 70% ETc irrigation application levels. The highest water use efficiency of 13.33 Kgm-3 was recorded from every row drip lateral spacing and irrigation application of 70% ETc. Therefore, onion could be irrigated every row drip lateral spacing with 70% ETc application to increase water use efficiency without a significant total bulb yield reduction.