Warming influences the yield and water use efficiency of winter wheat in the semiarid regions of Northwest China

Global warming directly influences crop growth and water use, which poses new challenges for food safety. The research base was at Guyuan Agricultural Meteorology Experiment Station in the semiarid region of Northwest China, and the soil was a loessal soil. A simulation experiment that warmed the farm soil with an infrared heater showed that winter wheat growth stages, including sowing-seedling emergence, seedling emergence-trefoil, trefoil stage-wintering, wintering-returning green, returning green-jointing, jointing-heading, heading-blooming and blooming-matured, were considerably affected by temperature rises. If the temperature increased 0.5-2.0 °C, the seedling emergence, trefoil, wintering, turning green, jointing, heading, and blooming stages were shortened by 2-4 d, 1-2 d, 10-12 d, 2-3 d, 1-3 d, 1-2 d, and 1-3 d, respectively, and the overall number of growing days was shortened by 15-28 d. Furthermore, a temperature rise of 0.5-2.0 °C improved winter wheat yield by 2.4%-7.9%. However, if the temperature rise was more than 1.0 °C, then the yield increase dropped by 2.4%-4.0%. Winter wheat water use efficiency increased by 14.7%-17.6% when the temperature rose by 0.5-1.0 °C. However, when the temperature increased by more than 1.0 °C, water use efficiency dropped by between 13.2% and 18.4%. If the temperature increased by 0.5-2.0 °C, then there was a considerable increase in the winter wheat protein content, but fat levels decreased. These results suggest that continued warming in the future will significantly influence the yield and quality of winter wheat.