Yield Loss and Grade Effects of Peanut Combine Speed Settings

Abstract. A research project was conducted to understand and quantify yield losses and grade associated with peanut combine harvesting. Research into this subject had not been previously reported, emphasizing the importance of results to peanut producers. On a peanut harvester, there are two main avenues for potential of peanut losses: losses as associated with the header (where vines enter) and losses associated with the cleanout (where the tailings exit). There were several operational variables that were tested, including: ground speed, PTO speed, and header speed. These variables were the only items that were changed throughout this study; other important operational settings, such as thrashing aggression and cleaning air, were set to normal operational settings. The study was conducted in Barnwell County, S.C. in November 2019 on Bailey variety peanut, a Virginia type. Tests were conducted on 4-row wide (3.86 m, 12.67 ft) plots that were 19.20 m (63 feet) in length, or 14.16 m2 (798.2 ft2) in area. The local growing season of 2019 was not ideal for harvesting, so the potential of weather related losses may have affected the amount of losses and harvested grade. Peanut yield, grade, header losses, tailings losses, and vine moisture were quantified for each plot. Peanut kernel moisture was not determined by plot, but measured to be 12% overall. The data from this study suggested and quantified effects of several economically important operational factors, some of which included: there was an optimum material throughput rate at which tailings yield losses were minimized, %LSK and foreign material decreased as tractor speed increased, and low relative header speeds significantly increased header losses. Knowledge of yield and grade effects of combine settings will assist growers in making economic decisions for peanut combine operation.