Water and soil nutrients remain the most preventive resources for irrigation agriculture. Poor water management and high chemical fertilizer costs remain a challenge in the study area.The main aims of this study were to evaluate soil water (SW)and nutrient dynamics and onion yield and Water Productivity under different irrigation techniques mainly; Conventional Furrow Irrigation (CFI), Alternat Furrow Irrigation (AFI), Fixed Furrow Irrigation (FFI),and Overhead Irrigation (OHI)techniques using field experiments and Hydrus Model. Hydrus-1Dmodel was used to simulate soil moisture content,actual evapotranspiration,and soil nutrient (N, P) leaching by the drainage water in the experimental treatments. The model performance was evaluated by comparing the measured and simulated daily Soil Moisture Content (SMC)nitrogen and phosphorus concentration in the drainage water for all irrigation treatments. Results indicated that the average SMC (cm 3 cm -3 ) ranges from 0.30 to 0.38 at 10cm and 0.27 to 0.37 at 20 cm depth.The seasonal drainage water was reduced to 86%, 87%, and54 % by AFI, FFI, and OHI treatments compared with that obtained in CFI. The NO3–N leaching was reduced 41%,71%, and 83% under AFI, FFI, and OHI compared with that obtained under full irrigation/CFI/. While, 60%, 66%, and 79.6% of PO4-P leaching werereduced by AFI, FFI, and OHI respectively as compared to CFI treatment. Besidesthe water and nutrient loss, the highest irrigation water productivity (IWP) (9.11 kg/m 3 ) was obtained from the AFI which was 39% higher than IWP over the CFI technique. The Hydrus-1D performance showed good agreement between the observed and simulated SMC indicated by high R 2 (0.55 – 0.81) and low NRMSE (0.01-0.09) and high dindex (0.95-0.99) values and with a very good agreement for NO3–N leaching on average (R 2 = 0.97, d index = 0.99 and NRMSE = 0.02).Similarly, for PO4-P, on average R 2 of 0.88; d index of 0.99 and NRMSE of 0.04) was obtained. Therefore, AFI is the most efficient nutrient-managed water-saving irrigation strategy for onion cultivation in the study area. Additionally, it could be concluded that Hydrus-1D could be a successful tool for predicting water and nutrient transport and helping for proper management decisions to improving water and nutrient management to maximize crop yield with limi ted irrigation water. Key Words:Soil Water Dynamic, Nutrient Dynamics,Irrigation Technique, Hydrus-1D.