Adoption of practices to mitigate harvest losses : ASSCT peer reviewed paper
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Harvesting Best Practice (HBP) recommends that harvesters maintain pour rates of 80-90 t/h, depending on make and model, and recommends extractor-fan speed guidelines that ensure minimal cane loss with low extraneous matter (EM). Exceeding the recommended pour rate overloads the cleaning capacity of modern harvesters and increases EM in the cane supply. To attempt to counterbalance the EM issue, it is usual to increase fan speeds above those recommended, resulting in greater cane loss. Use of HBP recommendations across the industry is low and full HBP adoption would substantially increase industry revenue. To address this, 43 replicated harvesting trials and workshops were undertaken in the 2017 harvest season across 12 sugarcane regions between Maryborough and Mossman. The performance of settings recommended by HBP were compared with each harvesting operation’s standard practice by assessing yield, CCS, bin mass, EM, fibre, sugar loss and revenue. To highlight the strong relationship between cane loss and excessive pour rates and fan speeds, treatments with higher pour rates and fan speeds and lower pour rates and fan speeds were also trialled. Results were presented to each harvesting group to inform their decision-making and promote HBP adoption. Cane loss, production and revenue data from 28 replicated and randomised trials were analysed to identify differences between industry standard harvesting practices and those recommended by HBP. We found that harvesters are typically operated at ground and fan speeds that are on average 1 km/h and 95 rpm above those recommended. The higher ground speed delivered an additional 22 t/h of cane into the machine on average but overloaded the cleaning capacity of the harvester. While the higher fan speed helped to remove the additional EM entering the machine, it also removed additional cane through the extractor with most being disintegrated, making it invisible to stakeholders. Testing indicated that mean sugar loss out of the extractor was increased by 0.15 t/ha compared with HBP settings, while there were no significant differences in EM or bin mass. Due to the additional cane being lost, less cane was delivered to the mill per hectare. Mill results across all trials identified that mean cane and sugar yields for the recommended practice were 5 t cane/ha (5.4%) and 0.8 t sugar/ha (5.7%) higher than standard practice. Neither CCS nor fibre levels were significantly different. The increased cane and sugar yields generated by the recommended settings boosted mean total grower revenue by $220/ha, equating to $173/ha after subtracting the additional harvesting costs (including fuel) and levies. Extrapolating these findings across the Australian green-cane-harvested area, full adoption of the recommended practices could deliver an additional 1.3 Mt of cane and 202,000 t of sugar valued at over $86 million for industry ($57 million in additional revenue for growers alone).