Rice production simulation under IPCC SRES A1B scenario in Fujian Province

Fujian Province was divided into three rice regions based on topographic features and rice cultivation patterns, whichwere double cropping rice region in Southeast Fujian, double cropping rice region in Northwest Fujian, single cropping rice regionsin the mountain areas of Northwest Fujian. 17 sampling sites and 9 representative rice varieties from the three regions were studied.Daily weather data for 2006—2007 and regional test yield data for the period were used to initialize CERES-Rice model parameters.Based on Special Report on Emission Scenario (SRES) on A1B scenario of IPCC, data from the PRECIS were integrated withCERES-Rice model to predict the influence of climate change on rice production in Fujian Province in the 2020s and 2040s. Thesimulation considered enhanced CO₂-fertilization effects and two cultivation modes under rain-fed and irrigated conditions. The resultssuggested that irrespective of rain-fed or irrigated rice, future growth durations shortened for three rice cropping regions.Growth duration of single cropping rice shortened the most (over 20 days) under the 2040s scenario. Future yields for single croppingrice and early rice dropped compared with yields under the baseline weather conditions. Yields for rain-fed and irrigated early rice indouble cropping rice region in Southeast Fujian dropped by 12.4% and 11.3%, respectively, while that for early rice in double croppingrice region in Northwest Fujian was minimal under the 2020s scenario. Because of negative contributions of mid-season varieties,yields for rain-fed and irrigated single cropping rice region in mountain regions of Northwest Fujian dropped by 7.1% and 2.1%,respectively. Reductions in output of all the treatments increased under the 2040s scenario. On the contrary, yields of late rice overthe same period were enhanced even though yield stability was the worst. Under the 2020s scenario, increasing yield rate of 21.0% oflater rice in irrigated double cropping rice region in Northwest Fujian and 10.6% in Southeast Fujian were noted, but slight yieldincreases for rain-fed these rice regions. The amplitude of rice yield increase dropped for all rice regions under the 2040s scenario.Soils during rice growth seasons in the research area were less moist, while irrigation demand as well increased in all rice crop regions.In summary, CO₂-fertilization effects improve later rice yields to certain extent with future climate changes. The overall outputof rice in Fujian Province slightly increases in the short-term. The rates of yield increase are 0.4% and 1.7% for rain-fed and irrigatedrice, respectively. However, yields decrease in the long-term with increasing temperatures. The main negative contributions wearefrom yields of single cropping rice and early rice.