Lessons from the past in weather variability: sowing to ripening dynamics and yield penalties for northern agriculture from 1970 to 2012

There is evidence for overall spring advancement and phenology shift across the northern hemisphere, including northern Europe, where cereals are grown despite the very short growing season. This study focused on one of the principal risks associated with the short growing season, weather-induced variability in sowing time. The aim was to characterize variation in sowing time, quantify the impacts on crop growth and document associations with weather conditions and variability. We also assessed whether any systematic changes occurred as potential signs of autonomous adaptation to changed conditions. Shifts in spring cereal sowing time had no consistent impact on time of maturity as a result of variable weather conditions. All spring cereal cultivars required fewer days, although more cumulated degree-days, to mature after delays in sowing. In the 1990s and 2000s, sowing tended to start earlier than in the 1970s and 1980s. This was attributable to earlier onset of the growing season. Furthermore, more favorable harvest conditions facilitated harvest after maturity. As more land has been allocated to late-maturing wheat (Triticum aestivum L.) compared with early-maturing barley (Hordeum vulgare L.) during recent decades, autonomous adaptation to climate change has already begun in the northernmost agricultural region of Europe.