Evaluating The Impact of Deficit Irrigation Scenarios on Paddy Rice at The Nile Northern Delta, Egypt

Deficit irrigation is considered an effective technique to increase water productivity under limited water conditions. Especially in the case of rice, one of the largest crops consuming water, efforts are being try to find ways to rationalize and increase water productivity. For this purpose, an experiment was conducted to estimate the impact of deficit irrigation scenarios during summer seasons 2018 and 2019 in a randomized complete block design with three replications. A medium duration variety (Giza178) was chosen for the study. Three deficit irrigation scenarios were applied (low, moderate, and high-water stress levels) which applied to three crop growth stages; vegetative (VEG.), reproductive (PRO.), and repining (RIP), in addition to the full growth period (FULL). Measurements included: [grain yield production (tons/ha), harvest index (%), weight of 1000 grains (g), and grain filling ratio (%)]. The water use estimation includes: [Water productivity (WP) and evapotranspiration productivity (ETWP)]. The results showed a high correlation between grain production and actual evapotranspiration (ET a /ET m ). Compared to the fully irrigated treatment, yield production at ripening stage treatments (8.52ton/ha) has the lowest reduction where the water productivity was 0.65 kg/m 3 , while the reproductive growth stage produced the lowest yield production and water productivity (6.96 ton/ha, 0.51 kg/m 3 ).