Impacts Of Climate Change To Rice Production And Adaptability Analysis Over Middle And Lower Reaches Of The Yangtze River

The average surface temperature of earth was recorded up by 0.6±0.2℃ over the 20th century, and in China 0.5℃⁰.8℃ increase was shown in the same period. Global climate change will affect greatly environmental, ecological and social economic systems. Since agriculture is one of the most sensitive sectors to climate change, it is of significance to evaluate impacts of climate change on rice (one of main three foodstuff crop). In order to reduce the harm of climate change, adaptability study is necessary, which is very important to crop supply safety in China.Rice experiment data and observed meteorological data at 48 early rice stations and 30 middle rice station from 1981-2003 were applied to analyze the relation of temperature and precipitation and rice components, focusing on analysis of three stages-flowering, premilk and late milk. The purpose of the study was to explore the impacts of historical climate change on rice elements. It was groundwork of impacts assessment of climate change in the futureBased on historical analysis, impacts of climate change on rice were evaluated. Firstly, crop model was validated using rice experiment data;Secondly, output of PRECIS (Providing Regional Climates for Impacts Stydies)driven by ECMWF reanalysis data (ERA) were employed to crop model to validate the linkage approach of PRECIS outputs with crop model;Thirdly, growth season and yield of rice at all station were evaluated under A2 and B2 scenarios in 2080s (2071-2100);Finally, some adaptive measures, such as adjusting planting date, cultivating and introducing new rice type, were presented by the results of simulation.The conclusions are as following:â… . Historical analysis: rain had negative effect on early rice at stages of flowering and milk;higher temperature would benefit early rice. Besides rain, durative hot temperature would add percentage of undeveloped grain and partially developed grain of middle rice. So historical global warming would affect middle rice over the middle and lower of the Yangtze river.â…¡. Validation of linkage approach of crop model and PRECIS output: Comparison between simulation and observation indicated that the approach of PRECIS coupled CERES-Rice was feasible and could evaluate change of rice yield and growth season under A2 and B2 scenarios.â…¢. Climate change impacts assessment: Under A2 and B2 scenarios, growth season of rice would be shortened, the most shortened days of early and middle rice would be 18 and 25 respectively;Without CO₂ direct effect, early and middle rice yield would be reduced -17%^-41% (A2 scenario) and -9.0%^-36.0% (B2 scenario) respectively;With CO2 direct effect, CO2 fertilization effect may offset negative impacts of climate change on rice and the yield of some rice station would increase, the most increase would be 26.0% (B2 scenario) .â…£. Adaptability study: Advancing planting date would be beneficial to early rice and postponing the date to middle rice. Yield early and middle rice would be rose by 16.6% and 17.3% compared with yield under the same scenarios;increasing the value of G4 (temperature tolerance coefficient) would raise yield up to 20.0% compared with yield under the same scenarios;otherwise,introducing tropic rice types condignly would also be adapted climate change. And it would be the most helpful measure, for the increase of rice yield would be 67.0% compared with yield under the same scenarios.