Testing the modeling capability of ORYZA2000 under nitrogen limit conditions in Northern Iran

Abstract

ORYZA2000 is a growth model for lowland rice (Oryza sativa L.) developed by the International Rice Research Institute and Wageningen University. This model has been evaluated extensively in a wide range of environments. The model ORYZA2000 simulates the growth and development of rice under conditions of potential production and nitrogen limitations. Crop simulation models could provide an alternative, less timeconsuming and inexpensive means of determining the optimum crop nitrogen requirement under varied nitrogen conditions. In this study, ORYZA2000 was calibrated and evaluated using data from experiments carried out in the North area of Iran. These experiments were performed on three varieties rice cultivar (Hashemi, Kazemi, Khazar) at various N rates (0, 30, 60 and 90 kg N.ha-1) in a RCBD in 2008, with 3 replications at Rice Research Institute of Iran, Rasht. ORYZA2000 was then applied to explore leaf area index (LAI), total above ground biomass and grain yield response to N fertilization by adjusted linear correlation coefficient between simulated and measured values (R2), T test of means, absolute and normalized root mean square errors (RMSE). Results showed that the grain yield was simulated with a root mean squared error (RMSE) of 388 (less than 15%) and total biomass with a RMSE of 782 (less than 15%).However, the prediction of leaf area index (LAI) at low level of nitrogen application was poor. Results specified too, model can use as an applied mean for estimate of rice grain yield at nitrogen levels management in a paddy soil of Guilan.