Growers of 38–cm (15–in.) narrow row corn typically use either a wider row cornhead or locally modify an existing head to this row spacing. A three–year field experiment compared visible machine losses of a 76–cm (30–in.) cornhead used on 76–cm (30–in.) and 38–cm (15–in.) rows and a single gathering chain 38–cm (15–in.) cornhead used on 38–cm (15–in.) rows. Total machine losses were divided into head and threshing/separating losses.

On matched row spacing, machine losses were generally similar between the 76– and 38–cm (30– and 15–in.) cornhead. However, one–year losses from the 76–cm (30–in.) cornhead were statistically lower. Machine ear drop losses were excessive [0.9 to 1.3 Mg/ha (15 to 20 bu/acre) in two of three years] and unacceptable when a 76–cm (30–in.) cornhead was used even at low 3.2–km/h (2–mph) travel speeds to harvest corn in 38–cm (15–in.) rows. At low feed rates, over 90% of machine losses occurred at the cornhead rather than in the threshing, separating, and cleaning areas. Header losses occurred due to ear drop from late season harvest and negligible losses inside the machine when operated at 4.8 km/h (3 mph). Although shelling of kernels on the stalk rolls was about 1% of harvested yield or less, ear drop loss from the cornhead was greater than this amount in two of three years.