Impact of thermal time shift on wheat phenology and yield under warming climate in the Huang-Huai-Hai Plain, China

Given climate change can potentially influence crop phenology and subsequent yield, an investigation of relevant adaptation measures could increase the understanding and mitigation of these responses in the future. In this study, field observations at 10 stations in the Huang-Huai-Hai Plain of China (HHHP) are used in combination with the Agricultural Production Systems Simulator (APSIM)–Wheat model to determine the effect of thermal time shift on the phenology and potential yield of wheat from 1981–2009. Warming climate speeds up winter wheat development and thereby decreases the duration of the wheat growth period. However, APSIM–Wheat model simulation suggests prolongation of the period from flowering to maturity (Gr) of winter wheat by 0.2–0.8 d∙10yr–1 as the number of days by which maturity advances, which is less than that by which flowering advances. Based on computed thermal time of the two critical growth phases of wheat, total thermal time from floral initiation to flowering (TT_floral_initiation) increasesd in seven out of the 10 investigated stations. Alternatively, total thermal time from the start of grainfilling to maturity (TT_start_ grain_fill) increased in all investigated stations, except Laiyang. It is thus concluded that thermal time shift during the past three decades (1981–2009) prolongs Gr by 0.2–3.0 d∙10yr–1 in the study area. This suggests that an increase in thermal time (TT) of the wheat growth period is critical for mitigating the effect of growth period reduction due to warming climatic condition. Furthermore, climate change reduces potential yield of winter wheat in 80% of the stations by 2.3–58.8 kg∙yr–1. However, thermal time shift (TTS) increases potential yield of winter wheat in most of the stations by 3.0–51.0 kg∙yr–1. It is concluded that wheat cultivars with longer growth periods and higher thermal requirements could mitigate the negative effects of warming climate on crop production in the study area.