Adaptive capacity of winter wheat to potential drought in Beijing–Tianjin–Hebei region under RCP8.5 scenario

Drought is more frequent and intensified due to global warming. Changed conditions in Beijing-Tianjin–Hebei region which is drier and warmer than before, make it necessary to investigate various optimized irrigation schemes in the winter wheat production. In this study, the DSSAT–CERES-Wheat model verified by field experimental data was applied to simulate the yield of winter wheat in Beijing–Tianjin–Hebei region from 2010 to 2069a under RCP8.5 climate scenario. The irrigation schemes were set up by adjusting the irrigation amount and irrigation structure to evaluate their adaptive capacity to climate change. The results showed that the regional average yield reduction rates of potential drought were 81.98% and 78.86% in 2010–2039a and 2040–2069a, which were higher in the north than that in the south. The yield reduction rate of potential drought increased with the decrease of irrigation amount, and the adaptive capacity declined with the decrease of irrigation amount, under the same irrigation structure. When 3-9-6 irrigation structure was applied, the regional averages of adaptive capacity to potential drought were 28.30%, 26.23%, and 22.22% in 2010–2039a, 29.00%, 26.67%, and 21.76% in 2040–2069a. The shortage of water resources caused by climate change and the possibility of drought limit the potential yield of winter wheat as high as 80% in this region. Priority shall be given to meeting the water demand in jointing stage and filling stage. Irrigation scheme of 3-9-6 structure with 180 mm irrigation amount shall be recommended and its adaptive capacity to climate change is the strongest in the near term and the medium-term. Even if a further 20% reduction in irrigation is applied (144 mm), the dual goals of reducing yield loss and saving 8.28 × 10⁸ t irrigation water per winter wheat season can be achieved.