EVALUATION AND APPLICATION OF THE ORYZA (v3) RICE MODEL UNDER DIFFERENT NITROGEN LEVELS IN LIAONING PROVINCE, CHINA

Climate change and the growing-demand for food security force growers to identify ways to improve both food production and resource-utilization effectiveness. Liaoning province is one of the major rice (Oryza sativa L.) production regions of China (CL), accounting for about 10% of the total national japonica cultivation area. In this study, the experimental regions were divided into five rice agroecological zones based on the difference in the planting area and climate conditions. Four nitrogen (N) management levels were designed by the application amount of N fertilizer. ORYZA (v3) model was calibrated, validated and applied to simulate yields under four N fertilizer levels. The results showed that ORYZA (v3) can describe grain yield and above-ground biomass well, and it can be applied to simulate growth in CL region. Scenario-analysis indicated that the simulated grain-yield responded strongly to a low nitrogen level. However, there was no significant grain-yield increase under more N. Significant spatial variation in the grain-yield was observed at different levels. Compared to regions with limited temperature and light resources during the rice growing-periods, the regions with more optimal conditions showed higher grain-yields under all four N levels.