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single row, as this would improve the consistency of biomass flow into the harvester with a more
continuous hedge-like structure in the crop and improve tree form from the harvesting perspective.
Multiple row (four rows and wider) belts and blocks are quite common at present, partly in
anticipation of the rules that will define a carbon sequestration forest. When the mallees are harvested
and the biomass is a commercial renewable energy resource, the definitions of carbon forests will
become relatively less important as the carbon “credit” value will be reflected in the renewable
energy market value of the biomass. The problems that arise with multiple rows are that:
• Inner rows are generally suppressed by competition within the mallee belt or block.
• When a crop’s outer rows are ready to harvest, the inner rows will still be too small for
efficient harvesting as there is a limit to harvesting speed.
• In wide belts and blocks, inner rows may never reach harvestable yield in an economically
realistic time (less than about ten years).
• The effect of inner row suppression becomes more apparent as the crop ages (Peck et al, 2011).
• The comparatively unproductive inner rows consume resources and reduce the growth of the
outer rows, which increases the interval between harvests and the frequency of returns to the
farmer.
Wide Swath
One of the few options available to the industry to reduce or maintain harvesting costs is to
implement a system that can increase the delivery rate of cane – more cane delivered is more income
for a relatively constant cost. In recent years, harvesters have reached the limit of increasing delivery
rates, due to the capacity of the machines to harvest more cane, farm layout and transport constraints.
It is clear that if a harvester is able to cut a wider swath in each pass, it will increase the delivery rate
of cane significantly and, therefore, contain the cost of harvesting. There are, however, some
significant constraints to the adoption of wide-swath harvesting.
There are some significant constraints to the adoption of wide-swath harvesting. These include the
lack of a factory-built production model 2-row machine, row-spacing configuration and associated
issues, component specifications and set up, transport from field to factory, farming systems to suit
wide-swath harvesting and industry acceptance, especially acceptance from growers.
John Deere are currently not manufacturing a double-row harvester for Australian row configurations
(1.5 m,1.8 m) because of the cost of manufacture. The factory production line produces one singlerow
harvester every 24 hours. Disruption to this product line when manufacturing a two-row
harvester, which has a low market demand, increases the cost of production. However, this situation
could change if there was sufficient demand for the product.
In Australia, there are a number of machine component configuration issues because there is no
standard row width across the industry.
There is currently limited data on the interaction of wide-swath harvesting on the cane transport
system and the effect that it has on the entire value chain. The mismatch of harvester output and the
mill transport ability causes inefficiencies in the current system. The introduction of wide-swath,
high-delivery-rate harvesting may impact negatively on existing mill transport infrastructure.
Mallee System
As discussed in the previous section, in mallee there appears to be little prospect of harvesting with a
wide front as rows need to be relatively widely spaced in the water-limiting environment.
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