Impact of delayed harvest on corn yield and harvest losses

Potential changes in yield and harvest losses that can occur while field drying corn are key considerations when evaluating harvest timing and energy costs associated with artificial drying. This study presents a three-year evaluation of corn harvest in Kentucky. Potential yield, observed yield, measured losses, and quality changes were monitored in a single field at multiple points over the harvest season to assess changes with respect to time and moisture. Measured losses were typically less than 1% of the potential yield in a good standing crop, consistent with results from cooperator combines (0.8% to 2.4%). When lodging was present, variability increased, and measured losses increased to between 5.3% and 9.1% of the potential yield, primarily as a result of ears missed by the combine head. No significant changes in potential yield were found, indicating potential yield was stable over the period examined. In two of the three seasons evaluated, extended delays resulted in an increase in lodging, and the observed yield was significantly reduced by up to 42.5%. Allowing the grain to field dry generally improved test weight; however, there was a trend of increased mold and other damage with prolonged field drying in one season.