Effects of sowing dates on grain yield of spring maize in the Three-Province of the Northeast China under climate change

Northeast China is the most sensitive area to climate change, where is also the important region of maiza production in China. It has both theoretical and practical significance to explore suitable sowing date of spring maize in three provinces of Northeast China (Heilongjiang Province, Jilin Province and Liaoning Province) under climate change. Meteorological data from 1981 to 2015 and agro-meteorological observations, including maize phenology data, yield data, and soil data from 1981 to 2012, were used to construct an APSIM-Maize model. The data were collected from the potential cultivation zones of spring maize in the three provinces of the Northeast China. The model was calibrated and validated in different climatic zones across the study area and related parameters were established accordingly. The potential yields and climatic potential yields of spring maize during different decades were then determined by setting different sowing dates based on the validated APSIM model. Combined with the indices of yield level and yield stability, the suitable range of sowing dates was determined under different conditions during different decades in each climatic zone. The results showed that the simulated values, including the days from sowing date to flowering date and maturity date, and the yield, were in agreement with the observed values for the seven spring maize varieties in the study area. This indicated that the APSIM model accurately simulated the phenological development and yield information of spring maize in the study area. Under the condition of sufficient irrigation, the suitable sowing date in the study area ranged from April 16 to May 19. A latitudinal distribution was exhibited for the suitable sowing date with the date moving earlier from south to north. The suitable sowing date of maize in the 1990s and 2000s was earlier than that in the 1980s, and this advanced trend was more significant in the 1990s than in the 2000s. However, under rainfed conditions, the suitable sowing period in the first, third, fifth, seventh, and ninth climatic zones displayed a delayed trend, with the delay ranging from 3 days to 6 days. Compared with the yield simulated using the sowing date applied in current production, the yield simulated using the theoretical suitable sowing date increased by 2.84%-9.96% in different climatic zones during different decades under rainfed conditions. This research supports the use of the APSIM model in Northeast China for applications such as the selection of suitable sowing dates under future climate scenarios.