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Calibration and Testing of the Aquacrop Model for Rice under Water and Nitrogen Management

Amiri, Ebrahim
Communications in soil science and plant analysis 2016 v.47 no.3 pp. 387-403
biomass, canopy, demonstration farms, field experimentation, grain yield, inflorescences, irrigation management, models, nitrogen, rice, statistical analysis, submergence, Iran
The objective of this study was to adapt and test the ability of the AquaCrop model under different nitrogen and irrigation management conditions in northern Iran. A three-year field experiment was conducted at the experimental farm of the Iranian Rice Research Institute in Rasht, Iran, from 2005 to 2007. Irrigation treatments comprised continuous submergence, irrigation at 5-day intervals, and irrigation at 8-day intervals. Nitrogen (N) application levels were 0, 45, 60, and 75 kg N ha ⁻¹. The goodness of fit between observed and simulated canopy cover, total and panicle biomass, grain yield, and final biomass was assessed by means of the coefficient of determination (R ²) and the absolute and normalized root mean square errors (RMSE ₙ). Results of the statistical test of the model for total and panicle biomass showed moderately high R ² (≥0.90) and moderate RMSE ₙ (6–36%) values, confirming that the model simulated the total and panicle biomass accurately. The model was simulated for CC with RMSE ₙ and R ² of 28 and 0.82, respectively. The agreement between predicted and observed rice grain yield and final biomass were with R ² of 0.81 and 0.82 and RMSE ₙ of 13 and 10% respectively.