SENSITIVITY OF CORN AND SOYBEAN YIELD IN ILLINOIS TO AIR TEMPERATURE AND PRECIPITATION: THE POTENTIAL IMPACT OF FUTURE CLIMATE CHANGE

The potential impact of climate change on agricultural production has frequently been evaluated at national and regional scales. This study considers the potential county-scale impact of climate change on corn (Zea mays L.) and soybean (Glycine max [L.] Merr.) yield in the important agricultural state of Illinois, USA. By identifying specific monthly climate variables (mean daily temperature and precipitation) to which corn and soybean yield is sensitive, this study compares monthly regional General Circulation Model (GCM) predictions with the monthly climate variables to which corn and soybean yield is sensitive to predict crop yield under future climate. Corn yield is negatively correlated with July and August temperature in much of the state, and positively correlated with precipitation from the previous September (in the central portion of the state) and July and August precipitation in most of northern and southern Illinois, respectively. Soybean yield is negatively correlated with mean monthly temperature in central and southern Illinois during the summer, and positively correlated with July and August precipitation in the same regions. Given the regional GCM prediction for increased summer temperatures and summer drought, both corn and soybean yield will likely decrease under future climate conditions. This is likely to be most pronounced in the central and southern portions of Illinois. Additionally, given higher summer temperatures, the risk of summer drought is more pronounced.