Grasslands of the World.pdf - Disasters and Conflicts - UNEP

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Grasslands of the world
Tropical pastures
Development of sown pastures was slower in the tropical areas, but the success
of introduced pastures in southern Australia during the 1950s provided a model
for similar development in tropical Australia. A number of species had been
introduced during the late nineteenth and early twentieth centuries, either
intentionally (e.g. Panicum maximum , Chloris gayana and Brachiaria mutica )
or accidentally (e.g. Stylosanthes humilis and Cenchrus ciliaris (Plate 9.4)).
Plant introduction and evaluation has continued, with initial emphasis on
grasses, but increasing attention has since been paid to legumes, especially
after a major expansion of research in the 1950s (Eyles and Cameron, 1985).
Most of the tropical pastures have been sown in Queensland, with smaller
areas in northern New South Wales, the Northern Territory and Western
Australia . Figure 9.6 shows a slow increase in the area of sown pasture in
Queensland until 1960, followed by a rapid expansion in pasture sowings
from the 1960s onwards, about ten years after a similar increase in temperate
Australia. This expansion continued until the 1990s, apart from decreases in
the late 1990s and late 1980s associated with disease outbreaks in Stylosanthes
humilis stands, poor returns for animal products and expansion of cropping
areas (Walker and Weston, 1990). About 70 percent of the area sown to
pasture has been sown solely to grasses. These grass -only pastures are mainly
on fertile soils, particularly those which previously supported brigalow
(Acacia harpophylla ) and gidgee (A. cambagei ). In contrast, sown grass-
Plate 9.4
Buffel grass (Cenchrus ciliaris ), the most widely planted grass in semi -arid tropical
areas. Buffel grass can support high levels of animal production, but has also
been listed as an environmental weed.
J.G. McIVOR