We recently plotted nine years of USDA yield data as a function of low temperatures (information captured from the entire Burrus footprint). The results are not surprising on beans. Frankly, we expected yield to be stronger when July is dominated by cool temperatures. When temperature remains too high, beans have a nasty habit of burning off more yield-producing “good stuff” than they create (the technical term is called ”photorespiration”).
The results are also pretty close to what we expected for corn. While cool July temps are not an ideal scenario for getting grain filled quickly, cool July temps do not necessarily kill corn yield either. Once July is over, the actual impact of temps on yield begins to taper.