Climate change and extremes have already affected every inhabited region globally, and climate warming has become the consensus of human society (IPCC, 2021). In the context of global climate change, extreme weather events have increased dramatically (Otto et al., 2020). With the increase in the frequency and intensity of extreme weather, climate change has a great impact on agricultural production and food supply security (IPCC, 2019).
Maize (Zea mays L.) is the world's highest yield food crop and the most important forage grain. In 2019, the worldwide harvest area was 2.39×108 ha, and the production was 1.41×109 tons (FAO: https://www.fao.org/faostat/en/#data/QCL). China's maize production and consumption level rank 2nd in the world, and currently, maize has become the most productive grain crop in China (Niu et al., 2013; Zhao et al., 2018b). The total harvest area and production in China accounted for 17.32% and 18.51% of the world, respectively, in 2019 (FAO, 2019). Northeast China, as an important maize commodity grain production base, accounts for more than 32% of the annual production of maize in China (Li et al., 2018; NBSC, 2021). There is no doubt that the yield of maize in Northeast China has a serious impact on maize yield in China.
Meanwhile, Northeast China is one of the sensitive areas to global climate change, and the increase in temperature is the main change trend. In the past 44 years, the annual average temperature increased at a rate of 0.04 ℃ yr− 1, the change in the average annual precipitation fluctuated, and the growth rate varied between − 3.19 mm yr− 1 and 6.73 mm yr− 1 (Zhao et al., 2007). There was a significant increase in warm-related climate year types from 1961 to 2013 (Liu et al., 2017b).
Due to the lack of preventive measures to address frequent extreme climate events and meteorological disasters, the average annual agricultural disaster area in Northeast China reached 6.43×104 km2 by 2016 (Guo et al., 2017). The impact of climate change on agricultural production is becoming much more serious (Tubiello et al., 2007; Challinor et al., 2014). For example, Wu et al. (2021) found that the maize yield decreased by 77.85 kg·ha− 1 (1.7%) for every 1 ℃ increase in temperature and increased by 0.645 kg·ha− 1 (0.014%) for every 1 mm increase in precipitation from 1979 to 2016. From 1961 to 2010, the climate production potential of maize decreased by 12.7 kg·ha− 1·yr− 1 on average due to the increase in thermal resources; the maize potential yield slightly increased by 5.9 kg·ha− 1·yr− 1 on average due to the increase in precipitation resources (Guo et al., 2014).
Most previous studies on the impact of climate change on maize yield in Northeast China have focused on the overall change trend of climate factors over a period (Liu et al., 2013; Zhao et al., 2015). Few researchers have analyzed the impact of changing normal climate and climate extremes on maize yield. Combining temperature and precipitation into different climate year types can more clearly reflect the temporal and spatial distribution and change in extreme climate. In this study, we took 1990 as the time node and divided 1960–2019 into two 30-yr periods (period I: 1960–1989 and period II: 1990–2019). We combined annual mean 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. Then, based on the maize yield data simulated by a well-validated APSIM-Maize model, we analyzed the effects of normal climate and climate extremes on maize yield in Northeast China. The purposes of this study were to (1) explore the frequency changes in normal climate and climate extremes and (2) the changes in this impact in the two periods. The results of this research can provide a reference for focusing on climate extremes and disaster prevention and mitigation.