The objective of this study was the evaluation of the CERES rice model under different nitrogen- and water-management conditions in northern Iran. A 3-year field experiment was conducted at the experimental farm of the Iranian Rice Research Institute in Rasht, Iran, from 2005 to 2007. The experiment was established in a split-plot design with three irrigation regimes (continuous submergence, irrigation at 5-day intervals, and irrigation at 8-day intervals) as the main plot, four nitrogen levels (0, 45, 60, and 75 kg N ha−1) as the subplot, and three replications. Evaluation simulated and measured grain yield, total crop biomass, N content of grain, and crop biomass by adjusted coefficient of correlation and by absolute and normalized root mean square errors (RMSE). Results showed that predicted grain yields agreed well with observed yields (RMSEa =297 and RMSEn =8%). Simulated and observed total dry-matter yields were also in reasonable agreement (RMSEn = 862 and RMSEn = 10%). Observed and predicted N uptake by rice showed good agreement. The CERES rice model can be applied to research purposes (irrigation and nitrogen) under northern Iranian conditions.

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