Spatiotemporal variability of winter wheat phenology in response to weather and climate variability in China

Weather and climate variability are predicted to impact food security by altering crop growth, phenology, and yield processes. Adaptation measures are critical for reducing future vulnerability of crop production to warming weather and climate variability. It is therefore vital to investigate the shifts in crop phenological processes in response to weather/climate variability. This study analyzes the trends in the dates of winter wheat (Triticum aestivum L.) phenology in relation to average temperature of different growth stage and the adaptation of the crop to weather/climate variability in China. The results suggest that the phenological phases of winter wheat have specific regional patterns in China. There are also significant shifts in the dates of winter wheat phenology and the duration of the growth stages in the investigated 30-year period of 1980-2009. While the date of sowing winter wheat delays, the dates of post-winter phenological phases (e.g., heading and maturity dates) advances in most areas of China. Detailed analysis shows that the changes in the phenological phases of winter wheat are strongly related to temperature trends. Temporal trends in phenological phases of winter wheat are similar in characteristics to corresponding trends in temperature. Although warming weather and climate variability is the main driver of the changes in winter wheat phenology, temperature is lower than before in most of the investigated stations during the period from heading to maturity-mainly the grain-filling stage. This is mainly due to the early heading and maturity dates, which in turn not only prolong growth stages but also enhance productivity of winter wheat. This could be a vital adaptation strategy of winter wheat to warming weather with beneficial effects in terms of productivity.