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August 7, 2002
In Western Australia’s higher
rainfall southern and coastal agricultural regions, lucerne has
a proven track record as forage and in cropping rotations,
however its winning ways elsewhere are less well known.
Research, supported by growers
and the Federal Government, via the
Grains Research and Development
Corporation, has therefore investigated its viability as a
pasture in medium to low rainfall areas.
Conducted by the Western
Australia Department of Agriculture’s Roy Latta and Keith
Devenish, the study compared the performances of lucerne and
annual legume pastures for water use, forage production and
subsequent crop yield in phase pasture-crop rotations.
Results were recorded from two
research sites in the central wheatbelt and nine commercial
sites in the central and northern wheatbelt, within the 300 –
450 mm rainfall zone, with a range of soil types and soil
acidity levels.
Slow establishment, sandy acidic
soils and extended dry summers reduced the productive stand life
of the lucerne to one to two years of a three year pasture, one
year crop rotation.
More than 30 plants per square
metre were established at all sites, however plant numbers
declined to less than 10 over an extended dry summer. Grazing
had less impact on plant numbers than dry summers.
In the project’s establishment
phase, lucerne biomass was 60 per cent of annual pasture, but
was 40 per cent greater than annual pasture in autumn/winter,
following autumn rain.
Lucerne’s high water-use meant
that after dry summers, crops following the lucerne phase could
have reduced yields due to soil water deficits.
The research demonstrated that
lucerne could be successfully established in the central and
northern wheatbelt, however establishment and management
strategies must be employed to help minimise the production
losses in response to low annual and summer rainfall.
Recommended strategies include
sowing lucerne at 2 kg/ha in alternate rows with a companion
field crop to help account for low production in the
establishment phase and removing lucerne in the spring prior to
returning to crop, to allow for available soil water and
nitrogen to accumulate.
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