Thermal Time Requirements for Maize Growth in Northeast China and Their Effects on Yield and Water Supply under Climate Change Conditions

Northeast China (NEC) is a region sensitive to climate change. However, the adoption of long-season maize cultivars in NEC has caused substantial yield increase under change conditions. It important determine whether such cultivar adoptions are effective throughout whole sustainably grain yield. In this study, phenological observations and meteorological data at six sites from 1981 2018 were used detect thermal time (TT) trends during growing period. TT, as parameter for measuring changes cultivars, was crop simulation model CERES-Maize examine variations produced with different × combinations decades. NEC, both TTs emergence anthesis physiological maturity showed significant increasing 2018. Simulation results humid areas revealed that adopting longer-season 2000–2018 increases, ranging 6.3% 13.3%, compared 1980s. stations semi-humid areas, decrease or small (from −12.7% 8.0%) when adopted 2000–2018. For decreasing ratios rainfed no water-stress (Yrainfed/Yno water-stress) lower Yrainfed/Yno values indicated sensitivity production water, which attributed TT precipitation. Our indicate that, area, limited by water after introducing higher requirement Therefore, securing food supplies will depend on increases water-use efficiency levels other adaptive strategies, varietal diversification, drought-resistant varieties, conservation tillage irrigation.