Lucerne is a valuable deep tap rooted perennial legume that can produce fodder throughout the year. Traditionally the main growing season for Lucerne has been through spring, summer and early autumn but many new varieties have now been bred with improved winter activity. Lucerne is able to fix its own nitrogen and in turn build soil fertility. It is also a popular choice when a rising water table, erosion or salinity is an issue. Once established, Lucerne competes well with annual weeds, especially during summer. Lucerne provides high quality feed for grazing animals, as it is highly digestible and a reliable source of protein. Lucerne is also commonly conserved as hay, chaff, silage or cubes and pellets.
Choosing the right variety for your needs and environment is essential, i.e. winter dormant varieties (4-5) are better suited to hay production or frost prone areas compared to winter active varieties (8-9) that generally have a shorter stand life but are quicker to respond after grazing or rainfall.
Winter dormant varieties have a dormancy period triggered by shortening day length, a prostrate growth habitat and a broader, lower, more protected crown (growing point) compared to winter active varieties which have upright growth characteristics and a narrow crown which sits above ground level.
Another important consideration when selecting a suitable variety is the leaf to stem ratio. The quality of Lucerne hay is directly related to the amount of leaf present; highly winter active varieties generally have a lower proportion of leaf to stem and thicker stems.
Lucerne can be successfully established at various times of the year, whether it is sown in autumn, winter or spring; the time of sowing normally depends on the rainfall and climate of the region. Autumn establishment is better suited to winter active or highly winter active varieties as they have better frost tolerance. Delayed sowing allows the opportunity to improve weed control and seedbed preparation.
For spring established Lucerne aim to sow mid August onwards as the soil temperature begins to increase and daytime lengthens.
Most failures of Lucerne establishment can be related back to short cuts being taken in preparations.
Lucerne is an acid sensitive plant; low pH (high Aluminium) reduces root development so it is essential to correct soil acidity issues through lime application prior to sowing. A soil test is absolutely essential prior to sowing any new perennial pasture to make economic & accurate management decisions.
Spray out any old pasture/crops with glyphosate prior to sowing; speak to your local agronomist about the correct rate to use depending on the weeds present and their size. Also consider using a pre-emergent herbicide such as trifluralin. Good seed-soil contact is crucial due to the small seed size, rolling the paddock after sowing can be very beneficial, improving establishment rates. Sow the seed at 4-8 kg/ha (dry land) or 10-15 kg/ha (irrigated) at approximately 1-2 cm depth. Phosphorus is vital for early seedling growth therefore sow Lucerne with a minimum of 20 units of P per hectare. Molybdenum is also important for nodulation and nitrogen fixation, so ensure it is available.
Lucerne seed must be inoculated with the AL strain of rhizobium to ensure effective nodulation and prompt establishment. Coating the seed with lime is also recommended to protect the rhizobia. Many Lucerne seed varieties are now available with a long life coating.
Young Lucerne is very susceptible to insect damage; Red Legged Earth Mites can destroy the seedlings before they even emerge. It is highly recommended to utilise either seed treatments or a bare earth pre-emergent insecticide.
Allow the stand to reach approximately 20 cm high and ensure that the plants can not be pulled out prior to grazing. It is commonly recommended to allow Lucerne to flower in its first year, which allows the plant to build up levels of starch in the taproot. Monitor the first grazing carefully and remove stock before they begin to graze near the crown of the plant.
Rotational grazing (or strip grazing) is essential for productivity and longevity of the stand. Lucerne can withstand set stocking during spring provided sufficient moisture is available, but damage to the crown of the Lucerne plant needs to be closely monitored.
Lucerne is a popular choice for fodder conservation such as haymaking. The most nutritious part of the plant is the leaf, so it is important to retain as much leaf in the bale as possible. The time of cutting is a compromise between quality and quantity; early cut Lucerne will be highly nutritious compared to later cut stands which are higher yielding but reduced digestibility. The optimum time of cutting can be gauged by the appearance of 2 cm long shoots/buds from the crown across approximately 60% of the plant population.
Aim to mow early in the day and minimise handling during the curing process, in an effort to retain as much leaf as possible. When ready to bale, the Lucerne should still have slight toughness when twisted
Allow 28 days for winter active varieties between cuts or 35 days for winter dormant species.
Lucerne is commonly established under a cover cereal crop where it is a concern that cash income is required off the paddock during the first season. It is preferable to use a species with an upright growth habit and minimal tillers (to prevent shading) e.g. triticale and reduce the cereal sowing rate by approximately 50%, blocking every second row.
Lucerne growth in normally slowed during winter allowing annual weeds to compete and further reduce the vigour of the Lucerne. Winter cleaning is the use of selective herbicides to remove target weeds from the stand mid-winter. Speak to your local agronomist about the best options.
Cattle grazing Lucerne pastures during winter and spring are susceptible to bloat, therefore avoid placing hungry stock onto fresh Lucerne growth and always allow access to dry feed such as straw. The use of bloat (rumesin) capsules will greatly reduce the risk. Sheep are also susceptible to red gut during similar circumstances so it is essential to allow ready access to a dry feed source. It is advisable to maintain a vaccination program to prevent the incidence of pulpy kidney.
As the highly productive Lucerne stand starts to deplete later in its life span, it may require re sowing. It is best practice to completely remove the plants through herbicide application and allow three weeks before re sowing. Another option could be to over sow the Lucerne stand with an annual crop such as ryegrass or cereal with a minimum till machine such as a disc-seeder.
If you require any further information please call 03 57 787490.