Modeling risk analysis for rice production due to agro-climate change and uncertainty in irrigation water

This study proposes a risk analysis model for quantifying the insufficient risk of rice production due to the climate change and variation in irrigation water and cultivation area (named RA_RICE_UCW). In this study, the focus is on uncertainty in agro-climate factors (i.e., total precipitation, average temperature, total sunshine and average radiation) which account for the climate change, the irrigation water from the gauges, surface water and groundwater, respectively. The study data in the research area (Changhua County in Central Taiwan) for the model development and applicability contain 18 years of annual rice productions, agro-climate factors, irrigation water and the cultivation areas. Through the proposed RA_RICE_UCW model, it can be known that large variations in precipitation result in the insufficient risk of rice production (i.e., the probability of demand exceeding supply) and to a more significantly degree than the other agro-climatic factors. Although the temperature is supposed to affect rice production, its variation slightly impacts the insufficient risk of rice production in the case of the annual average temperature being helpful for rice growth. In addition, irrigation water stably supplemented from gauges can enhance the reliability of rice production. However, variation in irrigation water from surface water and groundwater more obviously gets rise to the insufficient risk of rice production than gauged water. Also, groundwater can effectively enhance the reliability of rice production, especially as the lack of irrigation water is supplemented from the gauged and surface water.