Modelling maize phenology, biomass growth and yield under contrasting temperature conditions

Crop modelling has become an effective means to assess climate change impact on crop yield and to assist in development of adaptation strategies. Previous studies found large uncertainty in simulated crop yields, especially beyond optimal temperature range. In this paper, we combined the data reported in literature and our controlled-temperature experiment to derive the temperature response functions of phenological development and biomass growth of maize crop based on the Wang-Engel function (Agricultural systems, 58(1): 1-24), and compared them with those adopted in two mostly used maize growth models APSIM-Maize and CERES-Maize. Our results support the previous findings that leaf elongation, leaf appearance and the rate of development towards flowering have the same temperature response. Our results indicate that a curvilinear response with cardinal temperatures of 5 degrees C (base), 30 degrees C (optimum), and 41 degrees C (maximum) best describes the maize developmental response to temperature. For radiation use efficiency (RUE-biomass growth per unit intercepted radiation) of maize, the corresponding cardinal temperatures are likely to be 2 degrees C, 24 degrees C, and 38 degrees C respectively. All the cardinal temperatures are lower than what are used in current APSIM model. Replacing the default temperature responses with the newly derived ones led to contrasting differences in simulated flowering and maturity time across China's Maize Belt, while the differences in simulated maize yield were relatively smaller. This implies the importance to use the correct temperature response in maize growth modelling so that the genotype by environment interactions in response to rising temperature can be correctly captured.