Dealing with salinity in Wheatbelt Valleys - Department of Water

In February 2001, a benchmarking trial was
commenced on “Bundilla”, as part of the Animal
Production from Saline Lands Initiative. Two
hundred merino wethers were introduced to
25 hectares and have been grazed there since.
Though the sheep had eaten all the meagre
groundcover by mid-March and only had
2 Kg hay/hd/week to supplement the saltbush,
they have maintained condition and gained weight
slightly. The wool on some of the sheep was dyebanded
and showed good growth of wool over the
period from February to May.
As mentioned above, Paradana balansa was tried,
but with a minimum rainfall requirement of
400 mm per annum, and “Bundilla” averaging
around 330 mm, it was unrealistic to see this as
the answer. We needed an annual pasture plant,
preferably a legume, with salt and waterlogging
tolerance that would be suited to the lower rainfall
areas.
In 1998, 1 kg of a new selection of balansa
(frontier) was obtained, and this showed promise.
Lloyd
Growth in the first year was impressive, with
subsequent years’ growth also above expectations.
One advantage seems to be the large amount of
bulk it produces in late July when there is little
other feed available. Subsequently, more of the
balansa variety frontier has been planted. In
conjunction with this, and with the evidence of the
watertable drawdown by the saltbush, the rows of
saltbush have been placed further apart to allow
seeding machinery to move between the rows to
plant the clover. Sheep have been grazed on these
paddocks since February 2001.
Trials will be commenced in 2001 to determine
actual water use by saltbush and distances that
rows of saltbush can be placed apart and still
obtain sufficient watertable drawdown and salt
leaching to allow annual cereal crops and pastures
to be grown successfully.
In spite of the limited growth of annuals, significant
increases have been seen in sheep grazing days in
some of the saltbush areas.
Table 2: Sheep grazing days on one 30 ha paddock over the summer of 1993/94. The area was direct
seeded to saltbush in August 1991 and grazed lightly in autumn 1993.
Date in Date out Total days Sheep numbers Sheep days
02/11/93 06/11/93 5 1,300 6,500
06/11/93 13/11/93 7 2,000 14,000
03/01/94 07/01/94 5 650 3,250
08/01/94 11/02/94 35 500 17,500
12/02/94 05/03/94 22 200 4,400
06/04/94 11/04/94 6 660 3,960
12/04/94 17/04/94 6 1,220 7,320
56,930 sheep days @ 30 ha @ 365 days per year = 5.2 DSE/ha (annualised basis)
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