Assessing cane and sugar losses utilising world-class methods

Harvester operators have immediate feedback on parameters such as bin weight but no feedback on levels of cane loss being suffered – this is an ‘invisible’ loss. This leads to machines being operated at settings conducive to high cane loss, to the detriment of all sectors of the industry. To mitigate this, industry bodies have demonstrated the magnitude of cane loss by running cane-loss trials with individual harvester operators. Several cane-loss measurement strategies have been used. ‘Mass Balance’ (MB) trials, where cane loss is inferred by the difference in clean cane yield from different treatments, are expensive to run and, because the cane loss is the difference in two large but variable numbers, achieving statistical significance is difficult. The alternative ‘direct measurement’ of cane loss uses the In-field Sucrose Loss Measurement System (ISLMS) and is logistically simpler and has been used extensively by productivity staff. However, the magnitude of losses recorded have not been consistent with expectations, resulting in some ‘downgrading’ of the significance of cane loss. The importance of adhering to the rigorous ISLMS protocols and using a single experienced technician has been highlighted as the most appropriate mitigation of this ‘downgrading’. A large-scale program has demonstrated to industry the magnitude of cane loss under different field and harvesting conditions. Both MB and ISLMS techniques were used in 42 fully replicated trials across the Australian industry. Whilst the aim of the trial program was to demonstrate the impact of different harvester settings on the economics of the sugarcane value chain, the project allowed the different cane-loss measurement systems to be compared, and strategies developed to enhance the accuracy and repeatability of both systems. The number of trials allowed comparison of both measurement systems to assess infield and delivered yields. The magnitude of cane losses observed during these trials and the impact of field variables and machine settings on cane loss are reviewed. Overall, thinner stalked cultivars and shorter billet length both significantly increased cane loss at any nominated harvesting speed or extractor fan speed setting. It was more difficult to achieve high levels of statistical significance with the MB protocol than with the ISLMS, but the magnitude of losses indicated by the latter were lower. The importance of rigidly following the defined protocols for both systems was also re- affirmed. Key words Harvesting, losses, mass balance, in-field sucrose loss measurement