Sustainable grazing on saline lands

W W W . i n d u s t r Y. n s W . g o V . a u
N AT I V E C O U C H G R A S S E S F O R
R E H A B I L I TAT I O N A N D G R A Z I N G
O N A S A LT S I T E – W E S T H U M E
Case study – Albury
s u s ta i n a b l e g r a z i n g o n s a l i n e l a n d s
NSW GOVERNMENT RESEARCHERS
BURRUMBUTTOCK, NEAR ALBURY
grazing and to assess the amount (mass) and forage
quality of the herbage produced.
Soil test results are in the Appendix.
The problem
The West Hume Landcare Group commenced in 1990.
Salinity has been a growing concern for members since
the group’s inception. Salinity continues to express itself in
isolated parts of the catchment and group members were
keen to investigate more productive options for discharge
sites in the future.
The Landcare group, in conjunction with researchers
from the then Department of Natural Resources,
selected a saline site near Burrumbuttock for a series of
plant evaluation trials. The site was traditionally moist
throughout the year but very wet in winter. In recent
years, the site has been much drier because of drought.
Trials began in October 2001 with a preliminary screening
trial. This was followed in August 2002 by a more
quantitative study (Trial 1 below) and in August 2004 by a
dietary preference study (Trial 2 overleaf ).
Most, but not all, of the accessions evaluated were
native warm-season perennials and were established
vegetatively in late winter to early spring. Native species
were selected because they were less likely to become
weeds (though this was not guaranteed) and may even
enhance local biodiversity.
Trial 1
This replicated small-plot (0.5 m × 0.5 m) trial assessed
survival, vigour, ground cover, herbage production and
(laboratory) forage value for the following (for scientific
names see Appendix):
• commoncouchgrass
• Australiansaltgrass
• salt-watercouch
• Condaminecouch
• marinecouch
• Malleelovegrass.
During the second growing season, plants were cut every
4 to 6 weeks from October 2003 to April 2004 to simulate
Results: Trial 1
This section comes entirely from a journal article by the
researchers:
Semple WS, Cole IA, Koen TB, Costello D and Stringer, D
(2006) Native couch grasses for revegetating severely
salinised sites on the inland slopes of NSW. Part 2. The
Rangeland Journal 28, 163–173.
The text below is, wherever possible, direct quotes from this
paper, with occasional slight adaptation only when needed.
Condamine couch
‘Relative to the other species, Condamine couch
consistently produced the lowest amounts of
herbage mass …’
‘Groundcover was low …’
‘Nevertheless it appeared to be a relatively ‘benign’
species, which, despite its ability to produce long
stolons, is not reported to be weedy in its natural
habitat … Hence, it would appear to be of limited
use for pasture production but may be suitable for
revegetation in conservation areas.’
Mallee love grass
Survival of Mallee love grass was acceptable, but vigour
and groundcover performance were unexceptional.
As a consequence, this grass was not included in
the subsequent herbage mass and forage value
assessments. It did not appear to be a candidate
for use as a production species, but being relatively
benign and with no known weed potential it may have
application in salinised conservation areas.
Australian saltgrass
This species had sharp underground shoots that
grew vigorously, resulting in relatively quick spread.
Survival was high, as was vigour, throughout much
of the year. However, it was adversely affected by
regular cutting, and the promise of high herbage mass
production throughout the season was not realised,
being similar to those of common couch and marine
couch. Although protein content was similar to those
of the other species, digestibility and energy were
consistently and often significantly lower, and fibre
Trial 2
usually higher, than in the others, suggesting it has
limited application as a forage plant.
This replicated trial (conducted in a new area with
5 m × 10 m plots) compared dietary preferences for some
of the native grasses with those for some non-natives.
Its ‘aggressive’ growth here was surprising, and its
reported survival in non-saline areas urges caution
in its use as a revegetation species outside its natural
habitat. Its adverse reaction to regular cutting may, if
stock can be made to eat it, offer a potential method
of controlling this potentially weedy species.
The trial was sown and planted in late August 2004.
The soil was already damp, and there was a storm
(5 to 7 mm rain) the day after sowing. No fertiliser was
applied.
Common couch, salt-water couch and marine couch
The native grasses were established vegetatively at 1 m
spacings:
In terms of groundcover production, survival and
vigour, all species performed well.
• commoncouch
In terms of herbage mass, salt-water couch was the
best performer (up to 70 kg/ha/day), whereas marine
couch and common couch were low producers (up to
25 kg/ha/day), at least under a regular cutting regime.
Salt-water couch also produced herbage mass with
higher digestibility and energy than did marine couch
and common couch. Protein was similar in all species
throughout the growing season.
• salt-watercouch
• Australiansaltgrass
Two introduced pasture grasses were sown at 20 kg/ha
with a plot-seeder:
• ‘Tyrrell’tallwheatgrass
• ‘Demeter’tallfescue.
Marine couch was adversely affected by regular
cutting; this suggests that it may not be appropriate
for ‘saline pastures’ unless appropriately managed.
In addition to these five species, untreated control plots
(with naturalised annuals) were included in the design.
The native grasses remained dormant until early
November 2004. Tall fescue and tall wheatgrass
germinated about 4 weeks after sowing.
Note: This trial was part of a wider one that involved trials
in central NSW as well. For conclusions on these species
over all sites, see the journal article already mentioned.
Dale Stringer
Dale Stringer
Case study – Albury
N A T I V E C O U C H G R A S S E S F O R R E H A B I L I T A T I O N A N D G R A Z I N G O N A S A LT S I T E – W E S T H U M E
Some of the grass species in their small plots in 2003.
One grass plot being assessed in 2003.
s u s ta i n a b l e g r a z i n g o n s a l i n e l a n d s
Dale Stringer
Small mobs of sheep were used in short grazing trials to
assess the relative dietary preferences of sheep for these
species in different seasons. The grazing observations
were conducted in January, May and November 2006.
Samples of each species were collected in May and
November 2006 for feed quality analyses.
Results: Trial 2
Feed quality
Feed values were analysed for each species. The results
are summarised in Table 1.
In May, the nutritional value of the native grass species
was lower than those of the two introduced species and
the annual species.
Sheep grazing plots of the grasses in the experiment to determine
grazing preferences.
Dale Stringer
Spring 2006 was very dry, and the annual grasses had
dried off. The November nutritional values of the annual
grasses, common couch and Australian saltgrass were
lower than those of the introduced species or salt-water
couch.
Grazing preferences
In their second summer the pastures were established
enough to graze. Small mobs of sheep were used by NSW
DPI staff to graze the plots for short periods to determine
the relative acceptability of the grasses to sheep.
Table 2 shows the relative grazing preferences for each
species.
Preferences changed between times, with common
couch preferred more in the warmer months. Although
tall fescue and tall wheatgrass had high overall nutritional
values, the grazing preferences did not reflect that
quality. This might have been due to the fact that these
plots were mown in the weeks immediately before the
preference observations.
Researchers observing sheep grazing the grass plots.
Table 1. Feed values in Trial 2
Tall fescue
Crude protein (%)
Digestibility (%)
Metabolisable energy (MJ/kg)
May 2006
Nov 2006
May 2006
Nov 2006
May 2006
Nov 2006
14
10
62
58
8.9
8.7
Tall
wheatgrass
14
11
62
56
9.1
8.2
Common couch
Australian
saltgrass
9
6
42
47
5.5
6.2
9
8
53
55
7.6
7.8
Salt-water
couch
7
16
54
64
7.6
9.1
Untreated naturalised
annual controls*
22
9
60
50
8.4
6.9
* Mainly sea barley grass and annual beard grass.
Table 2. Relative grazing preferences in Trial 2
Tall fescue
Tall
wheatgrass
January
May
November
0
0
0
–
+
0
++ Strong preference + Low preference 0 expected chance – least preferred
Common couch
Australian saltgrass
Salt-water couch
Untreated Control
++
0
+
0
0
–
–
0
+?
0
0
0
Case study – Albury
N A T I V E C O U C H G R A S S E S F O R R E H A B I L I T A T I O N A N D G R A Z I N G O N A S A LT S I T E – W E S T H U M E
IMPORTANT NOTE
APPENDIx
These two trials produced results that represented
performance at this site, with its unique soil
characteristics, in the climatic conditions prevailing in the
brief periods in which measurements were taken, and
with the accessions of plant species chosen. They do not
represent definitive results for these species that can be
used for recommendations on their performance at all salt
sites, but they make good contributions to knowledge in
this area.
Scientific and common names of native and exotic (*) grass species
used in the trials
Acknowledgments
The information on Trial 1 comes from Bill Semple (retired,
formerly researcher with NSW Department of Natural
Resources) and from the paper mentioned, of which he is the
lead author. The information on Trial 2 comes from Dr Greg
Lee, Livestock Research Officer, Industry & Investment NSW.
David Costello, formerly West Hume Landcare Group and
Dale Stringer, Murray Catchment Management Authority.
Scientific name
Cynodon dactylon
Distichlis distichophylla
Paspalum vaginatum
Sporobolus mitchellii
Sporobolus virginicus
Eragrostis dielsii
Thinopyrum ponticum
Festuca arundinacea
Rainfall during trial (mm) (average annual rainfall = 601 mm at
Albury)
Jan
Feb
Mar
Apr
May
Jun
2004
12
0
0
19
39
111
2005
72
82
10
15
5
104
2006
6
6
34
40
19
30
Jul
Aug
Sep
Oct
Nov
Dec
Total
2004
51
61
52
8
111
75
539
2005
40
100
106
88
46
54
722
2006
38
11
27
2
23
2
238
NSW Salt Teams.
Prepared by Luke Beange, Advisory Officer,
Industry & Investment NSW
Common name and accession/cultivar
‘Aberdeen’ common couch grass*
‘Lake Charm’ Australian saltgrass
‘Ootha’ saltwater couch
‘Carop’ Condamine couch
‘Port Macquarie’ marine couch
‘Lake Charm’ Mallee love grass
‘Tyrrell’ tall wheatgrass*
‘Demeter’ tall fescue*
Topsoil (0 to 10 cm) characteristics for Trial 1*
Estimated ECe (dS/m)
pH (1:5 soil:water)
Mean
9.1
9.1
Range
0.7–33.5
8.7–9.7
* From Semple WS, Cole IA, Koen TB, Costello D and Stringer, D (2006) Native couch grasses for
revegetating severely salinised sites on the inland slopes of NSW. Part 2. The Rangeland Journal 28,
163–173.
Disclaimer
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(Industry & Investment NSW) 2010.
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