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Figure 2.4 Wheel spacing 1.5 m row spacing – 1.85 m wheel spacing
Figure 2.5 Wheel spacing: 1.85 m wheel spacing - dual row
The industry is moving towards a controlled traffic system and uniform row-spacing to increase
production, reduce costs and remain competitive. However, the industry does not have a standardised
row-spacing configuration as has happened in the cotton, vegetable and other industries both in
Australia and overseas.
Mallee System
In the moisture limiting wheatbelt environment, row spacing is not a critical agronomic factor, in that
a single row can exploit the moisture resources of the soil volume under a strip of land several metres
wide. There is no agronomic advantage in spacing rows less than 3 metres apart, and current
indications are that the most efficient row spacing may be much wider than 3 metres in a two row belt
(Peck et al, 2011). Unfortunately some of the existing resource is planted on less than 2 metre row
spacings and it is anticipated that these will not be harvestable unless some rows are removed.
A row spacing of 3 metres or more will accommodate harvesters and haulouts 2.5 - 3 metres wide
over the outside of the tyres or tracks. Wider machinery wheel spacing would be undesirable as it
would require specialised floats for machinery transport and possibly escorts and subject to daylight
hours only for road transport.
A plant spacing within the row of 2 metres offers a reasonable compromise between minimising the
cost of establishing the crop (seedling costs and other costs are primarily determined by the length of
row) and maintaining a consistent flow of material into the harvester. Larger spacings would make
the feed to the chipper less consistent, even though mallee production per kilometre of row may not
be affected by the larger intra-row spacing.
Because of the need to space rows widely and the flexibility available in intra-row spacing, there is
no anticipation of needing to harvest two rows simultaneously. If higher plant density per kilometre
of harvester travel is found to be desirable, it would preferrable to reduce the intra-row spacing in a
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