Simulation of Rice Leaf Area, Yield, and Nitrogen Content in Different Nitrogen Utilization Management via the ORYZA2000 Model

In order to simulate yield, leaf area, and nitrogen content in rice plant by using the ORYZA2000 model under different nitrogen fertilizer amounts and various splitting approaches, a factorial experiment based on a randomized complete block design with three replications was carried out at a research farm located in the Mazandaran Province (Babol) during 2017-18.

The first factor comprised four nitrogen fertilizer rates (50, 90, 130, and 170 Kg n ha−1, supplied as urea) and the second factor comprised various fertilizer splitting appraoches (T1: 70% basal+ 30% in tillering stage; T2: 33.33% basal+ 33.33% in tillering stage+ 33.33% in panicle initiation stage; T3: 25% basal+ 50% in tillering stage+ 25% in panicle initiation stage; T4: 25% basal+ 25% in tillering stage+ 50% in panicle initiation stage).

 The results demonstrated that the model successfully simulated grain yield, biomass, grain nitrogen, and total nitrogen with RMSEn of four, four, nine, and six percent in calibration, and five, four, four, and eight percent in validation, respectively. The mean square error for the leaf area index was 0.5 and 0.4 in the model’s calibration and validation, respectively.

Based on the results obtained, the ORYZA2000 model can be used as a suitbale simulation model for selecting the best strategy for enhancing rice yield under different nitrogen fertilizer management in the rice-rich regions of northern Iran.