Quantifying the indirect effects of different air pollutants on crop yields in North China Plain

Abstract

High concentrations of air pollutants could affect crop yield directly via influencing crop physiology and indirectly via regulating climate conditions. How multiple air pollutants affect crop yields directly and indirectly remains elusive in the North China Plain (NCP), which is the hotspot of air pollution and crop production. Here, we construct data-driven models to quantify the indirect effects of four major air pollutants on the yields of winter wheat and summer maize through modulating climate variations in the NCP during 2005–2020. Our results show that wheat has a greater negative sensitivity to absorbing aerosol optical thickness (AAOD), ozone concentration (O _3 ), sulfur dioxide concentration (SO _2 ) and nitrogen dioxide concentration (NO _2 ) than maize. The indirect effects of AAOD, O _3 and SO _2 in November and O _3 in April control wheat yield variation, while the indirect effects of AAOD and O _3 in June, O _3 and SO _2 in July, O _3 and NO _2 in August, and O _3 in September dominate maize yield variation. Our results emphasize the indirect effects of air pollutants on crop yield via regulating climate variations, which has great implications for improving our understanding of air pollution-climate-crop interactions and guiding targeted adaptation and mitigation efforts.

Keywords

• crop yields
• air pollutants
• indirect impacts
• North China Plain
• path analysis
• random forest model