THERE are cattle producers who have outlaid significant capital in establishing leucaena-based pastures, but are not fully utilising the productive capacity of this high protein leguminous browse shrub.
Queensland Primary Industries and Fisheries senior pasture agronomist Stuart Buck said that from his over-the-fence observations, far too many leucaena stands were growing too tall, allowed to flower and set seed.
Mr Buck, who leads the QPIF-funded 'Accelerated adoption of leucaena' project, said that ideally the leucaena should be rotationally grazed at heavy stocking rates to maintain a short, bushy shrub with maximum edible leaf and small stem forage.
"Once the leucaena flowers, the amount of woody biomass increases dramatically and the plant puts its energy into reproduction producing multiple seed pods rather than vegetative leaf growth," Mr Buck said.
"Under a rotational grazing system, the leucaena-grass pasture should be heavily stocked at a beast to 0.4 hectares at a stage when the plant produces maximum forage based on an eight to 12 week grazing cycle depending on rainfall.
"Stock should then be removed when about 10 per cent of leaf material remains.
"Under a continuous grazing system, the recommended stocking rate is a beast/1.5ha."
Mr Buck said current estimates placed Queensland’s leucaena plantings at more than 200,000ha and the 300-strong producer representation on The Leucaena Network had documented a Code of Practice that all growers should follow.
"That Code states that growers must manage leucaena to minimise seed production to avoid the environmental weed potential resulting from plant escapees outside the grazing paddock.
"If the leucaena growth within the row does get out of hand, mechanical trimming is a recommended management tool but it should not have to be a regular maintenance activity when leucaena grazing is well managed."
Mr Buck said current recommended row spacing for leucaena was now being questioned and planning was underway to investigate row spacing and planting rates.
Producer members of the Mackenzie River CQ BEEF Group aim to progress a proposed on-farm study as part of an 80ha leucaena planting on Lauchie and Carlie Ward's Dingo district property, Namgooyah, in spring this year.
The Wards are looking for a better balance between leucaena and sown pasture.
They believe planting on 12m wide rows should enhance the quantity and quality of the pasture mix. They intend sowing a 40ha paddock on 4m strips set on 12m centres within the established buffel pasture.
The Namgooyah project will incorporate another two 20ha fenced paddocks sown on 6m and 9m row spacings with comparisons to be made between planting single and double rows.
Within the 40ha wide-row planting, half will be planted at the accepted commercial rate of 2kg/ha and the balance at 1kg/ha.
Mr Buck said the on-farm project would quantify the liveweight production and economic benefits of a range of land preparation and planting techniques through to 2010.
Leucaena at Beef 09
Producers can explore opportunities for leucaena development at the 'Advances in sustainable leucaena production' seminar at Beef Australia 2009 at Rockhampton on May 5.
The seminar will be chaired by QPIF senior pasture agronomist Stuart Buck with presentations from Scott Dalzell from the University of Queensland (UQ), The Leucaena Network’s Kevin Graham and beef producers Ron Carige and Tom Wagner.
The seminar will cover the latest leucaena research findings, management, and impact on producer’s bottom line.
The Leucaena Network will also have a display at the Beef 2009 Trade Fair.
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