Spatiotemporal changes of rice phenology in China under climate change from 1981 to 2010

An examination of multiple spatiotemporal changes in crop phenology is critical for enabling regional agricultural activities to adapt to climate change. This study utilizes observed phenological data on early, single, and late rice collected from 39 agricultural meteorological stations in China over the 1981–2010 period to investigate changes in 10 phenological dates and three growing periods. Trends in air temperature, precipitation, sunshine hours, and growing degree days over the study period were also recorded. It was found that, on average, the dates of sowing (0.03 d a−1), emergence (0.01 d a−1), booting (0.00 d a−1), heading (0.05 d a−1), milk ripening (0.22 d a−1), and maturity (0.08 d a−1) were delayed across all stations, whereas the dates of trefoil (0.07 d a−1), transplanting (0.07 d a−1), regreening (0.11 d a−1), and tillering (0.11 d a−1) were advanced. There were different trends among different growing periods. Across all stations, on average, a slightly reduced trend for vegetative (0.00 d a−1) and reproductive growing periods (0.01 d a−1) was observed, while an extended trend for whole growing periods (0.03 d a−1) was found. Sensitivity analyses of rice growing periods and climatic factors indicated that increases in temperature and sunshine hours tended to reduce lengths of the growing periods at most stations, whereas precipitation has tended to extend the lengths of the reproductive growing periods over the past decades.