Top tips for planting leucaena

Considering investing in leucaena pastures or wanting to plant more? All the latest information on planting and establishing leucaena will be shared with producers during a paddock walk at Emerald, Queensland, on 10 August 2015.

Department of Agriculture and Fisheries (DAF) Queensland pastures agronomist Stuart Buck will share his knowledge on leucaena establishment, including paddock and soil type selection, agronomy, and grazing management in the paddock at two potential leucaena sites in the Emerald area on Monday 10 August.

Stuart has offered Friday Feedback an insight into his talk, based on the guidelines established by DAF for successful leucaena site selection and planting.

Here are the top tips:

Location, location: Leucaena performs best in tropical climates (hot, wet summers and mild winters - average annual rainfall above 600mm) and effectively stops growing when the average day temperature falls below 15°C. Leucaena will grow in a wide range of soils but is most productive in fertile (high phosphorus and alkaline pH), deep (>1 m), well-drained soils (intolerant to waterlogging). Leucaena performs best in soils with phosphorus above 20mg/kg, sulfur above 5mg/kg and good levels of trace elements, particularly potassium and zinc. It is susceptible to frost and so is more productive in frost-free areas.

Be prepared: Seedbed preparation and weed control are the keys to successful establishment. Control woody regrowth prior to establishment of leucaena. Fallow to store a minimum of 60 cm of soil moisture (this may take three to nine months). Plant sufficiently large areas or fence small areas to protect them from hares, wallabies, kangaroos and emus etc. In weedy paddocks (especially broadleaf weeds) ensure sufficient preparation time to deplete the weed seed bank, or use residual herbicides.

Row design: Align row direction for ease of mustering. Also consider erosion risk during paddock preparation and establishment. Where possible, provide water for stock in laneways. In paddocks with good quality grass, planting in strips can be effective but the prepared strip need to be at least 4m wide. Row spacings from 5m to 12m are used commercially.  If rows are too narrow, grass persistence will be poor (shading) and grass production low (competition). If rows are too wide, vigorous grasses compete for soil moisture, and nitrogen benefits are diluted.

Sowing time: Plant when soil temperatures are above 18°C. Follow-up rainfall will greatly assist establishment hence time sowing before or when there is the highest chance of rainfall. Avoid planting times when there is a high risk of hot, dry conditions during establishment (e.g. during spring). Aim to sow 2kg/ha of high germination ‘soft’ seed. Ensure the seed is mechanically scarified and inoculated with correct rhizobium. Plant the seed into wet soil sufficiently deep to stay wet for a week, but no deeper than 5cm.  Run presswheels to the side of the seed, not over the top.

Careful selection: Four commercial cultivars are available, all of which are susceptible to psyllid attack:

1. Peru is shrubby with good basal branching. Peru has been superseded by newer varieties.
2. Cunningham is more productive than Peru, however is a prolific seeder and is susceptible to psyllids.
3. Tarramba is taller, more tree like, produces less seed and has greater early seeding and cold vigour. It is susceptible to psyllid attack but grows sooner after psyllid damage.
4. Wondergraze is the latest release which has similar early seedling vigour and psyllid tolerance, but is bushier than Tarramba.

The good news: A new psyllid resistant variety is soon to be released. It will be highly suitable for coastal districts or environments where psyllids are highly prevalent. Seed for sowing in commercial paddocks should be available after 2016.

Take control: Weed control during establishment is critical for success. Use a residual herbicide (eg Spinnaker®) at planting over the rows to control broadleaf and grass weeds. Alternatively, inter-row cultivate to control weeds, particularly if legume weeds (e.g. sesbania) are a problem. It is important to control soil insects during establishment.

Warning: Protect the long-term future of leucaena as a pasture plant by stopping it becoming a weed around your farm or neighbouring properties. Do not plant leucaena close to waterways or boundaries to minimise the weed potential.

Information

Download a copy of MLA’s Leucaena: A guide to establishment and management

For general information and advice, call DAF on 13 25 23 or www.daf.qld.gov.au

Leucaena establishment and paddock walk

When: 9am-1pm, 10 August 2015
Where: Fairways House - Glendarriwell Road, Emerald, Queensland
RSVP: 7 August 2015 to Byrony Daniels T: 0427 746 434 E: byrony.daniels@daf.qld.gov.au