Combine Losses From Wide and Narrow Corn Rows

Growers of38-cm (15-in.) narrow row com 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-cm (30in.) and 38-cm (15-in.) cornhead, however, one year lower losses from the 76-cm (30-in.) cornhead were statistically less. Machine ear drop losses were excessive (0.9 to 1.3 Mglha (15 to 20 bu/ac) in 2 of3 years) and unacceptable when a 76-cm (30-in.) cornhead was used even at a slow 3.2 kmlhr (2 milhr) travel speed to harvest com in 38-cm (15-in.) rows. Over 90% of machine losses occurred at the cornhead rather than in the threshing, separating, and cleaning areas. This may have occurred due to ear drop from late season harvest or negligible losses inside the machine when operated at 4.8 kmlhr (3 milhr). Although shelling ofkemels 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 ofthree years.