To evaluate the effect of water stress at different crop growth stages on yield, yield components and water use efficiency, a field experiment was carried out in 2015/2016, 2016/2017 and 2017/2018 for bread wheat (Gambo variety) at Werer Agricultural Research Center. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications having 15 experimental treatments. Combination of water stress with crop growth stages was applied in the major investigation of the experiment. The highest grain yield was obtained from the control treatment irrigation at all stages (no stress). Stressing irrigation water at initial stages and maturity stages gave second highest yield (29.23 and 28.57 qt/ha) and lower water use efficiency (0.43 and 0.35 kg/m 3) respectively. While irrigating only at the initial stage gave highest water use efficiency (0.79 kg/m 3) and lowest grain yield. Application of irrigation water at all stages except initial and maturity gives optimum grain yield (26.73 qt/ha) and water use efficiency (0.62 kg/m 3) for the study area. Therefore, wheat should not be stressed at development and mid stage to obtain optimum water use efficiency (WUE) without a significant grain yield reduction.

Water is a vital resource to sustain civilizations and pecuniary development and most importantly agriculture. Agriculture is the main contributor to the Ethiopian economy. The field experiment was conducted at Werer Agricultural Research center to evaluate the effects of drip and furrow irrigation under different irrigation levels on maize water use efficiency. The experiment was laid out in an RCBD split-plot arrangement where drip and furrow irrigations were assigned as the main plot and irrigation levels (100, 85, 70, and 55% of ETc) were assigned in the subplot arrangement with three blocks. The highest seasonal water requirement of maize was 701.7 mm at 100% ETc under conventional furrow irrigation which is considered as control while the lowest was 321.6 mm at 55% ETc under alternative furrow irrigation. The interaction effects of irrigation systems and irrigation levels have shown a highly significant (p<0.01) effect on water use efficiency. The highest (2.38 kg/m 3 ) and the lowest (0.60kg/m 3 ) water use efficiency were recorded from the plots treated with drip irrigation at 100% ETc and conventional furrow irrigation at 100% ETc treatments, respectively. In terms of water use efficiency and economic prominence, irrigating with a drip irrigation system with 100% ETc can be recommended for the production of maize in the study area.

Agriculture is the main contributor of the Ethiopian economy as it accounts for about 55% of the GDP, 60% of the foreign exchange earnings and provides livelihood to 85% of the population. The field experiments were conducted to evaluate the performance of drip irrigation systems werer agricultural research station, middle awash, Ethiopia. Middle awash is largest irrigated part of the country. It is well gifted with the land, sunshine and highly fortune in available water resources. Drip irrigation has greater water economy over other systems in arid and semi-arid regions characterized by high evaporation rates and it has the potential to increase yields of crops even with reduced irrigation water application. The performance of drip irrigation system was evaluated on the basis of parameters like emitter flow variation (q var ), distribution uniformity (DU), application uniformity (Ea), coefficient of variation (CV), statistical uniformity (SU) and Christiansen uniformity coefficient (UCC). High values of uniformity coefficient and uniformity of distribution are attributed to the effect land levelling. The hydraulic performance of drip irrigation result shows the emitter flow variation (0.07%), emission uniformity (92.2%), coefficient of variation (0.07%), Christiansen uniformity coefficient (90.8) and application efficiency of (85%).

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