Climate Change and Maize Yield: Extreme Heat at Flowering Impacts Chinese Production

This study explores the growing influence of temperature change on maize yield, particularly in relation to planting density. We combined statistical and process-based models to analyze the effects of short-term extreme heat at flowering on Chinese maize yield under a changing climate. Our findings demonstrate that heat stress around flowering has a more substantial impact on yields compared to heat at other points during the growing season, especially for temperatures exceeding 30ﾰC. Heat stress during flowering was responsible for approximately one-third of the total yield loss attributed to extreme degree days (EDDs) between 1990 and 2012.

The process-based model (APSIM-maize), incorporating a grain-temperature function, was subsequently applied. This model indicated that extreme heat at flowering amplifies the effects of climate change on maize production. The enhanced APSIM-maize model predicts an 8.7% yield reduction across the Chinese Maize Belt as EDDs increase by more than threefold at the end of the century (2070-2099) under a high emissions pathway (SSP585) compared to the baseline period (1990-2019).