Introduction to Australian Pastures
Australian wool is produced across three major production zones. AWI provides information on the characteristics of each region.
Wool is produced across a wide range of environments, from the dry pastoral zone to the high rainfall zone, and is governed by a variety of summer and winter rainfall patterns. This diversity of environments is mirrored by a diversity of pasture types.
Across this varying climatic landscape, wool sheep are grazed on a range of pastures: those dominated by natives in the pastoral zone to a mixture of native and introduced species and those dominated by introduced species in the high rainfall and sheep/wheat zones.
Management also varies accordingly. Introduced pastures generally require fertiliser and other inputs to maintain their productivity. Conversely, many native and mixed pasture swards receive little or no fertiliser.
Characteristics of the major wool production zones
In general, we describe three agricultural production zones for Australia:
- Pastoral
- Sheep/cereal
- High rainfall
The characteristics of each production zone are described in the following section.
Figure 1 - Sheep and wool production areas in Australia (from the Land and Water Resources Audit 1999)
High Rainfall Zone
The high rainfall zone receives more than 600mm of rain on average each year and carries 33 per cent of Australia’s sheep flock.
ABARE estimates there were 8,800 wool producing farms in the high rainfall zone in 2003.
Pastures cover almost 20 million ha of this area. Up to 50 per cent of native or naturalised pastures have an annual legume component such as sub clover (Trifolium subterraneum).
Exotic pastures cover 9.8 m ha and mostly contain a mixture of sub clover, white clover (Trifolium repens), balansa clover (T. balansae), red clover (T. pretense); perennial grasses such as phalaris (Phalaris aquatica), tall fescue (Festuca arundinacea) and cocksfoot (Dactylis glomerata), and other annual and perennial legumes and grasses. Around 145,000 ha are sown to lucerne (Medicago sativa).
Recent research reports indicate that naturalised pastures across the higher rainfall perennial pasture zone of south-eastern Australia have declined in productivity, while sown pastures have failed to maintain their initial productivity. The reasons cited include: grazing practices, weed invasion, increasing acidity, rising water tables and poor drought management.
Sheep/Cereal Zone
The sheep/cereal zone extends over almost 35 million ha in southern and eastern Australia and is characterised by annual rainfall between 300 and 600 mm.
ABARE estimates there were 15,700 wool producing farms in the sheep/cereal zone in 2003. Almost 55 per cent of the nation’s sheep are located in this zone.
20.6 million ha are classified as native or volunteer pastures with an exotic legume base, which are often the result of naturalised establishment rather than sowing.
Pastures are sown in approximately 13.5 million ha. The majority of these sown pastures are legume dominant pasture rotations that increase soil nitrogen levels and break disease and weed cycles between cropping phases.
These pastures typically consist of annual medics (Medicago spp) on neutral to alkaline soils and sub clover, balansa clover, arrowleaf clover (Trifolium vesiculatum), rose clover (T. hirtum), Persian clover (T. resupinatum) and serradella (Ornithopus spp) for acid soils. Lucerne is sown over 417,000 ha of the sheep/cereal zone.
Rising water tables, acidity and salinity are found within the sheep/wheat zone. For much of the zone the productivity of both volunteer and sown pastures is below theoretical optimums
Pastoral zone
The pastoral zone covers the majority of Australia’s landmass and is characterised by annual rainfall below 300 mm.
Sheep and wool production is a major agricultural activity in the pastoral zone below approximately 220 latitude. Above this line, tropical rainfall and climate patterns make it unsuitable for sheep. Approximately 12 per cent of Australia’s sheep are located in the pastoral zone.
The pastoral zone wool industry is based on grazing of native grasslands and shrublands, which have typically been invaded by naturalised exotic species such as barley grass, rye grass and trefoil.