Using corn and soybeans as their testing ground, researchers at Pacific Northwest National Laboratory devised methods to peer into the mechanisms that modulate crop yield variability. They used statistical models to examine how climate variability impacts yields of these popular bioenergy crops at the county level. Among climate factors, the team showed that temperature is predominant in corn-growing counties, both by volume and percentage of production. Precipitation has a similar impact. The amount of energy from the sun, or radiation, has a much smaller effect USA-wide on both soybeans and corn.