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Second year management $200
Subsequent annual manangement $60
Open paddock zone
Competition zone
of about 20 m
Tree belt
width 7 m
Competition
zone
Full agricultural production
Width of the competition zone
varies according to the soil
profile, time since last harvest
(the leaf area), and the age of
the trees.
Some of this zone may not be
cropped in the years when the
mallees are large and carrying
a substantial leaf area.
Alleys between belts are normally a
multiple of the widest cropping machinery
such as the boom spray
2 m
spacing
between
trees
crop
Interrow
the row
within
free
buffer
2 m 3 m 2 m
Figure 1.4 The mallee belt system integrated with agriculture
When trees are planted in alleys in a cereal production system, it should be noted that they need to be
regularly harvested to reduce the moisture competition with the adjacent crop, however mature trees
do provide a good wind break and important other collateral benefits such as resilient landscapes and
environmental biodiversity.
As the economics of efficient harvesting and supply is reviewed, there is an increasing move towards
block plantings to optimise the system and maximise the income, with opportunity to mix block
planting close to processor with alley planting in remote areas as part of wheat/pasture production.
Spacing requirement for bulk planting and roles of differing soil and rainfall regimes (compared to
alley planting) all need to be optimised, as does the role of density of trees on the makeup of biomass
(the proportion of leaves decreases with denser/closer plantings). The impact of planting layout on
harvester performance, along with planting on the contour verses in a straight line and associated use
of GPS guidance, are other important considerations.
Sugar system
The Australian sugar industry had been based on a burnt cane harvesting system since the 1930’s but
with the advent of large scale mechanical harvesting in the 1970’s and the demonstrated benefits of a
green cane trash blanket during the 1980’s the industry transformed to predominantly green cane
harvesting. Further detail on these systems is provided in Section 2.1 of this report.
Green cane harvesting provides substantial improvements in profitability through labour and cost
savings, reduced tillage and improvements in soil organic matter, nutrient retention, bio-diversity, soil
water retention and reduced costs of weed and insect control (Garside et al, 1997).
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