by Andrea Johnson, formerly NT DPIF
From Savanna Burning - Understanding and Using Fire in
Northern Australia, Tropical Savannas CRC, Darwin 2001
Heytsbury Beef ’s Flora Valley Station, 120 km east of
Halls Creek in the Kimberley region of WA, runs 10,000 breeders on
an area of 6500 sq. km. About half the property is dominated by
spinifex, and half is Mitchell grass on black soil downs. Rainfall
declines in a gradient across the property, averaging 560 mm around
the homestead to 355 mm in the southern part.
Wildfires, driven by strong south-easterly winds from July
onward, are a major threat to the more productive downs country
every year.
Burning on black soil country
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Burning Mitchell grass on black soil country
every few years freshens up the pasture and encourages grazing away
from water points. Photo: NTDPIF
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Wayne Bean, manager, and Ian Hoare, head stockman, burn black
soil country every two to three years to reduce the risk of
wildfire, remove old rank growth and to promote healthier
pastures.
They light many fires opportunistically during mustering, trying
to burn patches that were not burnt in the previous year. This
provides a natural firebreak as areas burnt in one year will not
burn again in the next.
They prefer a total burn—best achieved when in warm and
windy weather—lighting up early in the day and using
previously burnt areas to prevent fires from travelling too far.
After good rainfall (from November onward), the Mitchell grass in
the burnt areas recovers to produce ‘obviously better pick
and feed’.
Fire also reduces localised heavy grazing, particularly around
the major watering points, as stock move out across the whole
paddock to seek fresh growth on burnt areas.
Burning black soil should not be undertaken lightly, and other
good management practices have to be in place. Stock numbers must
match the area that is burnt to prevent overgrazing of fresh
regrowth and damage to perennial tussocks.
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Burnt Mitchell grass
Photo Ian Partridge
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Burning spinifex country
The red hilly spinifex country on Flora Valley is also burnt
regularly to prevent wildfires, promote new fresh growth as a food
reserve and to keep the country open for easier mustering by
reducing prolific growth of woody species.
Before fire was used on Flora Valley the station was one of the
poorest performing properties of Heytsbury Beef in the Top End.
Since Wayne has incorporated burning with his grazing management,
Flora Valley experienced the highest weight gains of all
properties—the same property, the same cattle, different fire
regime.
