This study was conducted to establish the optimal combinations among discharge rate,drip lateral depth,and irrigation frequency for drip-irrigated triploid Populus tomentosa pulp plantation through numerical simulation using the HYDRUS (2D/3D) software.First,the HYDRUS model was calibrated by comparing predicted soil moisture content during two irrigation events with field measured values.Then,aggregately 18 scenarios of different combinations among three discharge rates (1,2,and 3 l·h-1),three drip lateral depths (10,20,and 30 cm),and two irrigation frequencies (continuous irrigation,and pulsed irrigation with water applied intermittently in 30 min periods) were simulated.The results indicate that the RMAE of simulation results at the end of irrigation and approximately 24h later were 7.8 and 6.0% respectively,and the RMSE were 0.0361 and 0.0255 cm3·cm-3 respectively,which supports the use of HYDRUS as a tool for investigating and designing drip irrigation management practices.The combination among various discharge rates,frequencies,and drip lateral depth had an important effect on the root water uptake,surface evaporation and drainage,with scenario 3C10 and 3C20 had the relative high irrigation efficiency,which were 53.1 and 53.2% respectively.However,from the perspective of increasing irrigation efficiency and reducing the negative effects on the environment,scenario 3C10 is the better irrigation strategy,because scenario 3C20 had higher summation of soil evaporation and deep leakage while 3C10 had more water retained in the active root zone (0-30 cm).In conclusion,the combination of 3 l·h-1 discharge rate,10 cm lateral depth,and continuous irrigation is the optimal drip irrigation management strategy in our triploid P.tomentosa pulp plantation.