LAUSR

In the context of improving Water Use Efficiency, there is interest in deficit irrigation, which provides a means of reducing water consumption while minimizing adverse effects on yield. A field experiment was conducted at Ambo Agricultural Research Center, Ethiopia during 2017 dry season. The objective was determining effects of irrigation levels and mulching material on yield and Water Use Efficiency of Onion. The experimental design was in RCBD with three replications. The deficit irrigation levels 100%, 80%, 70%, 60% and 50% ETc used with the three mulching no mulch, straw and plastic mulch were used. The results revealed that the maximum yield of 47.25 ton ha-1 was recorded from 100% ETc with plastic mulch; whereas the minimum yield of 18.2 ton ha-1 was recorded from 50% ETc with no mulch. Higher Crop Water Use Efficiency and Irrigation Water Use Efficiency of about 8.48 and 7.63 ha-1mm-1 was obtained from 70% ETc with plastic mulch respectively. With 70% ETc and plastic mulch the water saved, yield reduction and Crop Water Use Efficiency were 109.5 mm, 25.10% and 8.48 kg ha-1 mm-1 respectively. Considering water saved and maximum yield, irrigation water application at 70% irrigation application levels and plastic mulch could be interested. The present study suggests that, in water scarce area, farming community can adopt deficit irrigation level with 70% ETc under plastic mulch.