关键词: 华北玉米, 气候平均态和极端态, 贡献率, 未来影响

Abstract:

This study investigated the spatiotemporal patterns of climatic indices and maize yields across 69 stations in North China from 1980 to 2018. A multiple regression model was established to quantify the contributions of temperature, precipitation (both in normal and extreme states), and solar radiation to maize yields. Additionally, the potential impacts of future climate change on maize yields were projected under two future scenarios: SSP1−2.6 and SSP5−8.5. The results showed that: (1) from 1980 to 2018, the growing degree days (GDD) and heat degree days (HDD) of maize exhibited a significant upward trend, with rates of 32.4℃·d·10y⁻¹ and 4.0℃·d·10y⁻¹, respectively. Conversely, freezing degree days (FDD) and solar radiation showed a significant downward trend, declining at rates of 3.2℃·d·10y⁻¹ and 59MJ·m⁻²·10y⁻¹, respectively. Spatially, precipitation and maximum daily precipitation were higher in the southeast than in the northwest, while the longest consecutive dry days were observed in the central North China. Maize yield significantly increased at a rate of 57.5kg·ha⁻¹·y⁻¹. (2) The contribution rates of climatic indices to maize yield were, in descending order: HDD (−28%) > precipitation (23%) > maximum daily precipitation (−16%) > solar radiation (−14%) > GDD (12%) > consecutive dry days (−6%) > FDD (1%). The total contribution of normal and extreme precipitation (45%) was greater than that of normal and extreme temperature (41%). (3) Under the SSP1−2.6 scenario, 78% of the study area was projected to experience negative meteorological yields between 2031 and 2060, slightly decreasing to 72% by 2100. In the more severe SSP5−8.5 scenario, this proportion was projected to increase from 80% (2031−2060) to a remarkable 94% (2071−2100). Overall, HDD exerts the most significant impact, leading to decreased yields, while precipitation plays a role in boosting yields, with its influence outweighing that of temperature. Future climate change could potentially result in substantial reductions in maize production across North China.

Key words: Maize in North China, Normal and extreme climates, Contribution rate, Future effects