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Figure 2.2 Biosystems Engineering prototype woody crop harvester
2.1.1 Machine Definition
The purpose of any harvester needs to be outlined and what it needs to do must be clearly defined.
The purpose will guide the development of design concepts and criteria incorporated into the design
of the machine and ultimately leading to identified opportunities to improve design and performance.
Sugar system
The ‘chopped cane’ harvester is a machine that combines the task of harvesting and cleaning
sugarcane crops. The ‘chopped cane’ harvester performs the basic functions of gathering and topping
cane, severing stalks at ground level, feeding cane through a chopper system where it is cut into
billets and delivering chopped cane directly into infield transporters. Depending on the cane
harvesting requirements the machine may perform the additional functions of removing as much dirt,
leaf and trash as possible from the cane supply (Ridge and Norris, 2000).
If a single product, sugar, is the supply-chain objective, only the cane (stalk) is of interest. In this
system model, bagasse (the fibre remaining after crushing) is burned to generate power for the sugar
mill, while leaves and tops of the plant are disposed of at least cost. However, the deteriorating
international competitiveness of the industry in recent years has accelerated the search for additional
products with potential to add value, i.e. to supplement the revenue stream.
Sugarcane can be harvested burnt, green or the whole crop. The requirements for each are quite
different.
2.1.2 Burnt Cane Harvesting
Until the 1940’s, most of the Australian sugarcane crop was hand cut green, with residual trash being
burnt on the ground. Burning prior to harvest was allowed in some mill areas to control Weil’s
disease (Leptospirosis). The shortage of labour, together with the increased output of manual cutters
in burnt cane, led to burning becoming standard practice after World War II.
Burnt cane harvesting involves burning the sugarcane before it is harvested. This removes leaves,
weeds, and other matter, which can impede the harvesting and milling operations.
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