Awash River is the main irrigation water source for mechanized farms and small land farmers established in the Basin for the last few decades. Recently, with the rise of Beseka Lake, the amount of discharging rate into the Awash has been a serious concern to Agricultural Production in the Middle and Lower Awash Areas. This study was conducted to evaluate the effects of Beseka Lake on irrigation water quality, soil physical–chemicals properties and Cotton yield. Seven levels of Awash River and Beseka Lake blended water (8, 10, 15, 20, 25, 30 and 50% of Beseka water) and a control (0% of Beseka water) as a treatment were arranged in randomized complete blocks design with three replications. Yield of cotton showed significant (p<0.05) difference among irrigation treatments and maximum yield of 41.393 q/ha was obtained from the control treatment and significantly differed from all other treatments. Blended irrigation water had impact on soil properties which decreased yield with increasing blending ratio. Soil properties, such as electrical conductivity (EC) (1.18), exchangeable sodium percentage (ESP) (12.95), as well as pH (8.66), increased due to blending effect of Beseka water. Blended irrigation water treatment ratio of 8% gave the highest yield (39.143 q/ha) and reduced yield by 5% as compared to the control treatment (41.39q/ha).
Key words: Irrigation water quality, blended irrigation water, Beseka lake, soil properties, cotton yield, awash river.