Investigating losses from green and burnt cane harvesting conditions

Abstract

Despite much research into the impact of high harvester pour rates and fan speeds on harvested cane yields, there has been low adoption of HBP (harvesting best practice) across the industry. Full adoption across the Australian sugarcane industry could increase industry revenue with no necessity for horizontal expansion (increase in cane land). In order to inform industry of the potential for significant gains, 95 replicated harvesting trials and workshops were undertaken during 2017 and 2018 across 12 sugarcane regions in Queensland and New South Wales. The performance of settings recommended by HBP was compared with each harvesting operation's standard practice by assessing yield, CCS, bin mass, extraneous matter (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. Cane loss, production and revenue data from the fully replicated and randomised trials were analysed to identify differences between industry standard harvesting practices and those recommended by HBP. Harvesters typically operate at ground and fan speeds at on average of 0.9 km/h and 95 rpm above those recommended under HBP parameters. The higher ground speed overloads the cleaning capacity of the harvester in delivering an average 21 t/h more cane though the machine. Consequently, fan speeds are increased to remove the additional EM (extraneous matter) entering the machine, which then removes additional cane via the extractor. This cane often disintegrated in the process, making much invisible. Trials indicated the average sugar loss out of the extractor increased by 0.15 t/ha over the HBP settings. However, there was no significant improvement in EM or bin mass. As a result of cane loss though the extractor, less cane per hectare was delivered to the mill. Mill analyses across the trials identified cane and sugar yields for the recommended practice were 4.9 t/ha (cane yield) and 0.7 t/ha (sugar yield) higher than standard practice. Neither CCS nor fibre levels were significantly different. Increased cane and sugar yields generated by the recommended practice translated to an increase in grower gross revenue of $181/ha., but reduced ground speeds increased the cost of harvesting by $61/ha. Subtracting the additional harvesting costs and levies from the additional grower revenue leaves a net benefit of $116/ha for the grower. Preliminary results of "good" burn trials indicate an improvement of $207/ha in grower gross revenue with lower fuel. Based on the green-cane results, full adoption of HBP could improve annual industry revenue by $44 million for growers at an additional cost of $17 million for harvesting (excluding incentives). Milling revenue would also improve by $25 million per year but this does not account for additional milling or transport costs. © 2021 42nd Australian Society of Sugar Cane Technologists Conference 2021, ASSCT 2021. All rights reserved.