Heat Stress and Low Humidity with Climate Change will be Hard on Midwestern Corn Crops

 

by Christina Whalen and Emil Morhardt

Maize (corn) production continues to be a very important source of food, feed, and fuel all around the world, but climate change has raised the concern about being able to maintain the yield rates. A negative relationship between extremely high temperatures (above 30˚C) and yield has already been observed in various regions. Previous studies have not been able to demonstrate which mechanism causes the correlation between extreme temperatures and yield, thus it is possible that the relationship reflects the influence of another variable, such as precipitation rates. There are other possible explanations for the observed relationships. This study explores the mechanisms used in other studies that document the importance of extreme heat on rainfed maize using the process-based Agricultural Production Systems Simulator (APSIM). The study asks three main questions: can APSIM reproduce the empirical relationships—what farmers are seeing on the ground?; if so, what does APSIM imply are the key processes that give rise to these relationships?; how much are these relationships affected by changes in atmospheric CO2? Continue reading