Drivers of Spatial Variability in Corn Yield Sensitivity to Heat in the US Midwest

Extreme heat is a growing threat to global agricultural production. Compound climate extremes, such as co-occurring hot and dry conditions driven by interactions between land and atmosphere, further exacerbate yield loss. Given the projected increase in such extremes, crop adaptation is becoming increasingly crucial to mitigate yield shocks and ensure food security. 

The US Midwest, responsible for about a third of global corn production, is a key region of focus. In this study, we find that the regional sensitivity of corn yields to extreme heat has shown an increasing trend over the past 6 decades. While this finding aligns with other studies indicating limited adaptation in the region, the spatial variations in sensitivity changes suggest more localized influences on crop yields. Using data from the USDA and ERA5, we explore the basis for this observed variability in sensitivity, with a particular focus on two management strategies—crop diversity and tillage practices—at the county scale to assess potential adaptation.