Cane loss due to basecutter and knockdown damage

It is well accepted in the Australian sugar industry that cane lost through the extractors of a chopper harvester is inversely proportional to the extraneous matter brought to the mill. Improved harvester design and operating practices have reduced cane losses to about 3% to 4%. This paper investigates the significance of cane damage on the amount of cane lost through harvester extractors. A wind tunnel was used to determine the terminal velocity of various billet fragments and other damaged billets. The terminal velocity of many of the billet fragments was found to be well below that of whole billets. In principle, current air velocities through the extractors should lift and remove these billet fragments. A field trial showed that the loss of cane due to splitting and separating billets into smaller fragments was responsible for more than 4% of cane loss, while that due to damage caused by excessive knockdown angles may be as high as 7.5%. These predicted losses suggest that a significant portion of current losses in the field during harvesting is attributable to cane damage.