Assessment of Stage-Wise Deficit Furrow Irrigation Application on Maize Production at Koga Irrigation Scheme, Blue Nile River Basin, Ethiopia

Efficient irrigation management has an imperative role in managing integrated water resources. Deficit irrigation water application is among the most effective water management solutions. This study was conducted with the aim of evaluating the performance of stage-wise deficit irrigation (DI) application on irrigation efficiencies and to identify crop growth stages during which the crop can withstand water deficit with limited effect on yield and water productivity (WP). Maize (Melkassa-4 type) was selected as test crop as it is known to respond well to deficit irrigation. The experiment was conducted at Koga Irrigation Scheme, Blue Nile River Basin. The field experiment was arranged in randomized complete block design (RCBD) with three replications. The result showed that level of stage-wise deficit irrigation water application had a significant (P<0.05) impact on performance indices except distribution uniformity. Application efficiency increased with deficit level increases. The maximum application efficiency (83.5%) was noted when 0.25ETc was applied throughout the growing season. Effect of stage-wise application level had a significant (P<0.05) effect on agronomic parameters. The highest yield (58.92 qt/ha) was obtained when full irrigation was applied in all growth stages. The highest Physical water productivity (CWP) (1.65 kg/m3) and economic water productivity (CWP) (4.17 Birr/m3) were obtained when 50% deficit applied during 2nd and 3rd growth stages. On average, the crop was found to be moderately sensitive to water deficit since the average seasonal maize response factor (Ky) (1.04) value is slightly greater than one. In conclusion, this study showed that much water is saved when the crop is stressed by 50% during 2nd and 3rd growth stages. Keywords : Deficit irrigation, irrigation performance indices, Koga irrigation scheme, stage-wise, water productivity.