Leucaena

Benefits of leucaena

Leucaena delivers great benefits where the environment and the production system are suitable. Benefits include:

• Sustainability - Planting leucaena offers the opportunity to sustainably intensify production on the best land. This frees other areas for conservation and protection from over-grazing.
• Longevity and cost reductions – a potential 30+ year productive life span makes leucaena more profitable than any other improved pasture. Despite its higher establishment cost, it replaces the need for annual forage crops.
• Drought proofing - leucaena is a deep-rooted perennial shrub legume. It keeps producing high-quality green leaf through the drier periods of summer, autumn and early winter.
• Improved soil fertility - nitrogen fixed by leucaena improves grass quality and quantity. It reverses the ‘nitrogen run-down’ seen in pure-grass swards.
• Better weight gains for longer - leucaena is the most productive and sustainable tropical forage legume. No other forage plant can put the same weight on stock over so long a period of the year.
• Top nutritional value - leucaena leaf is high in protein and is easily digested by ruminants.
• High palatability - cattle prefer leucaena to most other forages. This leads to high intake and subsequent weight gains.
• Market flexibility - excellent weight gains allow targeting of markets when prices are highest.
• Reduced soil erosion - planting leucaena and a vigorous grass across slopes encourages water infiltration and reduces run off.
• Prevention of rising water tables and salinity - leucaena's deep roots can extract water from the soil to a depth of 3-5m. This prevents rising water tables that can bring salt to the soil surface.
• Greenhouse gas reduction - Carbon is sequestered in the woody growth. Highly digestible leucaena diets can reduce cattle methane production by 20-30%.

Limitations of leucaena

Leucaena is not for everyone and before you start planting it is important to consider the following:

• Geography – leucaena is not suitable for the whole of northern Australia.

• Soil type – it grows best on deep fertile soils with more than 600 mm rainfall.
• Cost to establish - establishment can be slow and costly as leucaena seedlings suffer strongly from weed competition. Potential attack by insects, kangaroos, wallabies and hares is also a threat. Depending on the conditions it may take up to two years to establish fully during which time it can only be lightly grazed.
• Frost – its green leaf and stem can be frosted to ground level, but the plant will recover.
• Psyllids – these insects can damage older cultivars in humid environments with rainfall above 800 mm. The new Redlands variety of leucaena addresses this by being psyllid-resistant.
• Toxicity – leucaena can be toxic if the animals are not inoculated with special rumen bacteria. Unadapted animals can also experience short-term leucaena toxicity if they are not introduced gradually to leucaena.
• Environmental concerns – heavy seed production can occur without good management. Tall growth must be controlled by appropriate grazing or mechanical slashing.