Sowing and establishment

Soil Testing

Understanding the limitations of lucerne is essential, and factors such as low pH, Aluminum, and where it is located within the soil profile will determine if the paddock is suitable for sowing lucerne. Soil test at least 12 months in advance to allow enough time for deficiencies to be identified and fixed.

Note: Nitrogen is not normally applied as lucerne can fix Nitrogen during the growing season.

Paddock Selection

Correct paddock selection is a key driver for long-term lucerne stand persistence. When sowing, identify an area to plant lucerne (minimum of 12 months prior to sowing). When selecting a paddock, consider that lucerne will grow on a variety of soils with a preference to:

Deep, well drained soils of medium to light texture
Rich alluvial soils
Most of the red earth/red-brown earth soils
Well drained black/grey soils
Highly fertile/slightly acidic soils

Note: Established lucerne moderately tolerates saline soils, but seedlings are less tolerant.

Seedbed preparation

Poor weed control is one of the most common issues that lead to poor lucerne establishment. Soil type will determine the cultivation practice during seedbed preparation to ensure the soil is suitable for planting. This will aid the soil to seed contact at the time of sowing and provide good supporting moisture infiltration around the seed either after a rainfall event or irrigation. Weed control must start the year before sowing the lucerne to ensure adequate time and opportunity to control/remove any weeds present in the paddock. This should also reduce the need to use post emergent herbicides in the young lucerne crop as this can retard lucerne growth.

Correct paddock selection is a key driver for long term persistence of lucerne stands. The sowing depth needs to be managed as lucerne is a small seed and therefore only needs to be sown at no more than 15mm deep. This will enable the lucerne to germinate and the seedling to rise above the soil to begin photosynthesis.

Slugs

In recent years slugs have been a real problem in decimating newly sown pastures, crops and lucerne. Heavy soil types, summer rains and reduced tillage are all factors which promote the build up of slug populations. Inspect potential paddocks prior to sowing and if found contact your local agronomist for control of this devastating pest.

Established Stand Management

Weed Control

Identify weeds present
Always spray in winter for winter-cleaning weed control (i.e. when the lucerne is dormant)

Dryland lucerne stands should be sprayed every second year (at least)

Irrigated lucerne stands should be sprayed annually

Consult your local agronomist for chemical recommendations

Pests and Diseases

Identify early and graze or cut the stand (removing the pest feed source).
If pest infestations are high and are causing damage to yield, then using an insecticide is necessary
Early winter graze to reduce over-wintering aphid populations.
There are numerous Fleas (i.e. Lucerne Flea), Mites (i.e. Red Legged Earth Mite), Grubs, Weevils and Aphids that attack establishing lucerne stands. Monitor early (both beneficial and predators) to prevent rapid population build-up and damage – contact your local agronomist for control options.

Fertiliser

Soil test annually to ensure fertility is maintained and appropriate fertiliser is used.
Leaf analysis during active spring growth can also be used in conjunction with soil tests to check soil fertility and fertiliser type.
Apply the recommended lucerne fertiliser after the first cut in spring and then after every second cut, in a cut and carry system.
Grazed lucerne requires less fertiliser than hay cutting because nutrients are returned through dung and urine.

Irrigation

If irrigation is available, this can help when moisture is low. Although lucerne is highly drought tolerant, irrigation increases the potential to more than double the lucerne yield in dry years.

Weed invasion can occur when irrigated too frequently and immediately after cutting or grazing.

The optimum frequency and timing of irrigation is dependent on how much water the soil can hold, or your soils’ holding capability.
When demand for water is low, delay irrigation until new leaves are visible and are ready to expand and out-compete germinating weeds.
Roots grow at 1cm/day. Growth above the ground stops while reserves are put into the roots.

Mixed Swards

If you have never grown lucerne before, plant a pure stand of lucerne and learn how to manage it.

After the ideal areas of your farm for lucerne monocultures are established, there may be an option to look at lucerne/grass mixes on more difficult soils or topography. These range from lucerne with some grass to minimise soil erosion on wind prone sites, through to a grass pasture where lucerne is providing the legume component where other legumes (e.g. white clover) have failed. The management of lucerne/grass mixes is more complex and extra caution should be taken.

Research has shown that increasing distribution of feed over longer periods can be achieved by using companion species with different seasonal growth patterns.

Examples of companion species with lucerne include:

Phalaris
Chicory
Cocksfoot
Tall fescue
Plantain
Subterranean clover
Prairie grass
Oversowing annual ryegrass, oats or forage ryecorn
Undersowing with winter cereal crops

There are many positives and negatives associated with sowing a companion species – such as mitigating the potential animal health issues, but conversely reducing quality hay and herbicide control options. Consult your local agronomist on the best species or sowing practices suited to your farming systems.

Autotoxicity

It is well known that lucerne plants can produce chemical(s) which suppress the germination and growth of lucerne seedlings. This phenomenon is called autotoxicity.

Autotoxicity is difficult to detect and predict, as soil type, rainfall, management, age of the previous stand etc. all play different roles. Older lucerne stands are more prone to it than young stands because of the accumulation of the chemicals - in evolutionary terms the plant is trying to stop its seedlings growing where it already is.

For a thinning older stand, over sow Italian ryegrass (or similar) in autumn to get use out of the accumulated nitrogen and prolong the stand life. Alternatively, drill in a perennial grass and make it a pasture that might last another 3-4 years as your transition paddock.

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Grazing Management

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