ESTIMATION OF HARVESTER LOSSES BY DETERMINATION OF SUGAR IN HARVEST RESIDUE

CANE losses during harvesting are a major cost to the sugar industry and may cause environmental problems. Losses occur in the base cutters, choppers and extractors. These losses are difficult to measure directly because much of the lost cane ends up as shredded pulp or splattered juice. Large scale replicated harvesting trials in large even cane blocks have been used to estimate losses by a mass balance of cane harvested. These trials are very difficult and expensive to carry out and often the results are treated with scepticism. A simpler, more direct method of measuring cane or sugar loss was obviously needed. A method of measuring sugar content in harvest residue was developed by Bundaberg Sugar Ltd and BSES Ltd during the 2003 season. The method was first tested by adding known amounts of sucrose solution to clean trash and subjecting this to the extraction procedure. The recovery of added sucrose ranged from 82%–98% (average 90%); this was considered good enough to proceed to field trials. This new methodology was then used to measure sugar loss in the field from a series of harvester trials at Fairymead plantation. These trials showed the expected increase in sugar losses with increasing fan speed. The procedure was effective in accounting for 55% of sugar loss from the harvester as determined by the replicated mass balance trials. There was significant deterioration in sucrose content, probably due to the delays involved in transporting and processing the samples in the laboratory. There is a need to further develop the technique so that harvest sugar loss can be determined in the field by field/extension officers with all the required equipment carried in the back of a conventional vehicle.