Malaysian Journal of Sustainable Agriculture (MJSA)

Nepal’s agricultural sector is crucial for employment generation and GDP, but it is vulnerable to adverse weather and climatic conditions, particularly affecting rice production. The Decision Support System for Agro Technology Transfer (DSSAT) uses the Cropping System Model (CSM)-CERES Rice to simulate rice growth and development. This study used the DSSAT rice growth simulation model to assess rice production in the Terai region of the eastern province, specifically Tarahara. Data was collected from 2013 to 2018, using the NR 1190 (Radha-13) rice variety under long-term soil fertility experiments. The study found that increased atmospheric temperature, solar radiation fluctuations, CO2 concentration variations, and rainfall fluctuations negatively affected rice yield. Maximum temperatures increased rice yield proportionally, while decreased minimum temperatures led to significant yield loss. Changes in solar radiation intensity also negatively affected yields. The model indicated a linear increase in rice yield up to 600vpm of CO2 concentration, but beyond which the yield plateaued. Precipitation changes exhibited decreasing trends in yield, and the combined effect exacerbated the negative impact. The study also assessed best management practices (BMPs) for rice production in the study region. The optimal conditions identified included planting ten days earlier, an NPK ratio of 120:40:50, and a plant density of 130 at transplanting, resulting in a 23.49% increase in yield on applying all best management practices.