Abstract:

The goal of this study is to take the self-adaption of rice production in future into consideration in the climate change impact studies, to enhance its rationality. The first step we did was to classify Fujian Province into three rice regions according to the topographic features and rice-based cropping systems. Altogether 17 sites and 9 representative rice varieties with different maturity types were selected to conduct the simulation experiments. The second step, to generate climate change scenarios in two periods (1961–1990 and 2021–2050), based on three emission schemes (A2, B2, and A1B) in IPCC Special Report (SRES), combined with the Regional Climate Model of PRECIS. The third step to run CERES-Rice model under the three climate change scenarios to simulate the influence of future climate change on rice production in Fujian Province, without considering the self-adaption of rice production. The direct effects of CO2 enrichment on photosynthesis and transpirations were also included.The forth step, to assess the possible change in rice-based cropping system, varietal type as well as sowing date in future in the studied area, based on the simulated results and some climatic indices, and these changes could be regarded as the results of self-adaption adjustment in future. The fifth step, to run CERES-Rice model again under the three climate change scenarios using the possible cropping systems, varietal types and sowing dates after self-adaption adjustment. Finally, to assess change in rice yield, yield stability in different rice regions and the overall output of rice in the province in future with considering the self-adaption adjustment. The results indicated that the simulated yields of early rice in the Double Rice Region in southeastern Fujian under A2, B2, and A1B scenarios increase by 15.9%, 18.0%, and 19.2% and that of late rice increase respectively by 9.2%, 7.4%, and 7.4% when the self-adaption adjustment was considered, compared without consideration. In the Double Rice Region in Northwestern Fujian, the simulated yields of early rice increase by 21.2%, 20.5%, 18.9% and that of late rice increase respectively by 14.7%, 14.8%, and 7.2% under the three climate change scenarios when the self-adaption was considered, compared with without consideration. Similar results could be obtained in the Single Rice Region in the mountain areas of Northwestern Fujian. The simulated yields of single rice increase respectively by 4.9%, 5.0%, and 2.9% under the three scenarios, comparing the two cases with and without consideration of self-adaption. In this rice region, double rice might be grown in future in the site of Changting under the A1 and B2 scenarios. When the self-adaption adjustment was considered, the overall output of rice crop in Fujian Province under the three climate change scenarios would increase by 5.9%, 5.2%, and 5.1%, respectively. It is concluded that more optimistic results could be obtained when self-adaption ability of food production was taken into consideration.

Key words: Climate change, IPCC Emission Scenarios, Regional climate model, Fujian Province, Rice production, Self-adaption