Temporal and spatial variation in accumulated temperature requirements of maize

Temperature, especially accumulated temperature, is an important environmental factor that plays a fundamental role in agricultural productivity. To examine temporal and spatial variation in accumulated temperature requirements of maize as indicated by ≥10 °C accumulated temperature and growing degree days (GDD), we conducted experiments during 2007-2012 at 35 locations in seven provinces in the north spring maize region between 35°11′ N and 48°08′ N and 6 locations in four provinces in the Huanghuaihai maize region between 32°52′ N and 41°05′ N in China. The most widely cultivated maize hybrids of ZD958 and XY335 were used in this study. We found that the coefficients of variation for ≥10 °C accumulated temperature and GDD requirements were different during different growth periods, with a descending rank order of sowing to emergence > silking to maturity > emergence to silking > sowing to maturity and greater in the north spring maize region than in the Huanghuaihai maize region. The coefficients of variation were lower for ≥10 °C accumulated temperature than GDD requirements for both cultivars in both planting regions. Significant differences existed between locations and years for the ≥10 °C accumulated temperature and GDD requirements. These have implications for appropriate maize cultivars recommendation, and high and stable yield achieving by reasonably using accumulated temperature across different regions of China.