| Popis: |
Under climate change, increases in climate extremes have an enormous impact on maize production in Northeast China, which is the largest maize-producing region in the country. In this study, we combined annual mean air temperature and accumulated precipitation, used the 10th and 90th percentiles as extreme thresholds, and divided the years into 9 categories, including 1 normal climate, 4 individual climate extremes, and 4 combined climate extremes. Coupled with the simulated rainfed yield by a well-validated APSIM-Maize model, we compared the changes in the frequencies of climate extremes and their impacts on maize yield between two 30-yr periods (period I: 1960–1989 and period II: 1990–2019). The results showed that the occurrence of normal climate and all 3 cold-related climate extremes (i.e., Cold-Normal, Cold-Humid, and Cold-Dry) decreased during period II, while other climate extremes increased. Compared with the years with normal climate in period I the yield decreased by 4.01%. Compared with period I, years with 3 cold-related climate extremes increased the yield by 26.56%, 12.10%, and 6.68%, respectively. The years with 2 warm-related climate extremes (Warm-Normal, Warm-Dry), as well as Normal-Humid and Normal-Dry years, decreased by 6.39%, 24.12%, 5.10%, and 2.18%, respectively. Only with the increase in the occurrence of Warm-Humid did the yield increase by 11.69%. In future maize production in Northeast China, we can focus on the adverse effects of climate extremes such as Warm-Normal, Warm-Dry, Normal-Humid, and Normal-Dry. |
