Abstract: The study aimed to model the impacts of climate change on maize phenology. Henan province was divided into four agro-climatic zones and the genetic parameters of representative maize varieties in each zone were determined by calibrate and validate CERES-Maize model. Thereafter, the impact of future climate change on maize phenology was modeled based on future climate change scenarios (A2 and B2) for 2020s, 2050s and 2080s by adding the temperature and precipitation increments simulated by regional climate model (PRECIS) to the baseline (1961-1990). The study results showed that there were large spatial differences between genetic parameters of representative maize varieties in four zones. Required thermal time from sowing to flowering of maize varieties in western Henan was higher than other zones. However, required thermal time from flowering to maturity of maize varieties in northern and eastern Henan was higher than other two zones. Days from sowing to flowering were accurately simulated with RMSE <4.0d and NRMSE <10% for both the calibration and validation periods. RMSE between simulated and observed maturing date was lower than 4d for calibration period and 3-7d for validation period. NRMSE between simulated and observed maturing date was lower than 10% in all the zones except for western Henan. Simulated vegetative growth period and whole growth period of summer maize shortened by 4.7d and 12.9d on average under A2 scenario, and 3.1d and 8.6d on average under B2 scenario, respectively. The decrease in the length of maize growing period was in accordance with the increase in growing period temperature in different regions in Henan province, with the longest decrease in western Henan.

Key words: CERES-Maize model, Climate change, Phenology, Summer maize, Simulation