Rice yield under surface and subsurface drainage managements and evaluation of AquaCrop model

The simulation models that quantify the effects of different amounts of water on crop yield are useful tools for water management at the farm level and optimizing water use efficiency. In this study, the AquaCrop model was used for simulating rice yield under different surface and subsurface drainage managements. Required data were obtained from subsurface drainage pilot of consolidated paddy fields of Sari Agricultural Sciences and Natural Resources University during 2011and 2012 growing seasons. The calibration, validation and sensitivity analysis of the model was utilized to quantify and verify the effects of different water managements on rice yield using the measurements from field experiments. The model satisfactory (d> 0.91) simulated different parameters. The prediction accuracy was very high in the subsurface drainage treatments. The errors for grain yield and biomass simulations were, respectively, 13 % and 27 % for surface drainage treatment indicating the highest error under different drainage treatments. The average root mean square error for simulated grain yield and biomass was found to be 191.5 and 745.8 kg ha-1, respectively. The results demonstrated that the AquaCrop model is reliable in simulating growth and yield of rice under subsurface and surface drainage systems and can be used to improve irrigation and drainage management in paddy fields.