Impact of Variety on Cotton Yield Monitor Calibration

Abstract. Public and private research and demonstration efforts are essential to keeping US producers competitive with those in the rest of the world. While modern yield monitors for grain are able to harvest variety and hybrid trials without imposing variety/hybrid-related bias, many reports have indicated that cotton yield monitors are sufficiently affected by varietal properties to alter the inferences obtained from the data. With recently developed planters capable of site-specific planting of multiple varieties, a better understanding of the varietal effects on yield monitor calibration is essential. A field experiment was conducted in 2016 at the University of Missouri Fisher Delta Research Center Lee Farm near Portageville, Missouri, to compare yield monitor-estimated weights to observed weights in a replicated variety trial and investigate factors that could relate to any observed varietal effect. Six commonly planted commercial varieties were planted in a randomized complete block experimental design with four replications. Individual plots 15 m wide (16 rows) by 70 m long were harvested with a spindle picker equipped with a yield monitor. The harvested seed cotton from each plot was weighed and used to calibrate the yield monitor. Consistent with earlier studies, the calibration error varied significantly among the six varieties in the study; however, the statistical grouping did not change. Harvest load and observed yield were significantly correlated with calibration error, which may have been related to time of harvest. Additional studies are planned using a producer‘s late-model spindle picker with a different type of sensor.