Irrigation & Drainage Systems Engineering

Effect of Deficit Irrigation on Yield and Water Productivity of Irrigated Wheat (Triticum aestivum L.) in the Upper Nile River Basin, North West Ethiopia

Abstract

Atakltie Abebe* and Pratap Singh

The study was conducted at Koga irrigation trial and demonstration site in the upper Nile River basin, to evaluate the effect of deficit irrigation on yield and water productivity of irrigated wheat. The wheat crop was subjected to water stress by not irrigating during different crop growth periods, by reducing the level of irrigation and full irrigation during all crop growth periods. The field experiment was arranged in a randomized complete block design with three replications and seven treatments. It was found that different levels of soil moisture stress had significant (p<0.001) effect on plant height, spike length, number of grains per spike, above-ground biomass, grain yield, and irrigation water productivity. There was no significant difference in crop yield for 75% of ETc and no irrigation during the lateseason crop growth period as compared to 100% of ETc application. But, the irrigation water productivity observed at 75% of ETc application and no irrigation during late season growth period was significantly higher than 100% of ETc application. Imposing deficit irrigation during the late growing period and a deficit of 25%ETc thorough out the whole growing period saved 15% and 25% irrigation water compared to full irrigation practice over the whole growing period with insignificant crop yield decrease of 1.4% and 2% respectively. Irrigation of wheat to 75% of ETc, 50%of ETc, skipping irrigation during crop development period and skipping irrigation during late season period enhance the irrigation water use efficiency by 23.6%, 8.6%, 21.5% and 13.6%, respectively than the full irrigation practice.