A soil test is recommended before sowing lucerne as it will not tolerate acid soils with high aluminium. Soil pH (CaCl2) should be above 5.5. If the soil is acidic (less than 5.5), then lime is recommended to raise the pH level.
Lucerne requires free draining soil types and does not like waterlogged conditions.
2. Time of sowing
For higher rainfall southern regions, successful spring sowing of lucerne is achievable. This is due to control of winter weeds and rising soil and air temperature aiding establishment. Autumn sowing is recommended in low medium rainfall regions where the majority of annual rainfall occurs in winter.
3. Seed bed preparation and sowing
Weed control through spraying of glyphosate is recommended to achieve a knockdown. For autumn sowing lucerne, spray topping in the previous spring to reduce seed set of annual weeds before the autumn is another option. If the soil test suggests the pH needs to be raised, incorporation of lime can occur; this starts the process to turn the paddock into a fine, firm, weed free seed bed. Pre-emergent herbicide such as Trifluralin can be used at sowing to control weeds to give the lucerne the best chance to establish. Lucerne can also be direct drilled when there is adequate soil moisture.
Lucerne does not establish well from being sown too deep. The seed should be covered by 1-2 cm of soil. Using a roller after sowing is important to get good seed soil contact on lighter soils.
5. Seed treatments
Treating lucerne seed is recommended in any situation for successful establishment. Seed treatments for lucerne include applying Rhizobia to the seed to aid nodulation of lucerne roots. Apron fungicide and Poncho® Plus insecticide are also applied to provide each plant the best possible start to establish. This treatment is known as SowEasy KickStart™.
6. Fertiliser requirements at sowing
Lucerne requires phosphorus and nitrogen at sowing to aid strong establishment. Single super phosphate at 250-300 kg/ha or M.A.P or D.A.P fertiliser at 80-100 kg/ha is recommended to be drilled with the seed.
Consider the following three questions when deciding which variety to sow:
Quality of lucerne hay is directly related to the amount of leaf present relative to stem. Highly winter active varieties generally have a lower proportion of leaf to stem and thicker stems at maturity, when compared to more winter dormant varieties. However, management and disease will have a much greater effect on the proportion of leaf in hay than will the variety selected.
8. Top dressing of fertiliser
A soil test will assist in making fertiliser decisions for your lucerne stand. Annual applications of phosphorus, potassium and lime (Ca) are commonly applied to lucerne stands as these are the major nutrients removed in grazing and hay lucerne stands.
The following table shows the amount of key nutrients removed from one tonne dry matter of lucerne hay. Nitrogen is not normally applied as lucerne can fix nitrogen during the growing season.
|Nutrient||Symbol||Amount removed in 1t DM
of lucerne hay
Most lucerne diseases are infectious and are caused by living organisms such as bacteria, fungi, nematodes and mycoplasma-type organisms. They penetrate plant tissue by piercing the outer membrane of the plant. Most common fungal diseases in southern grown regions are damping off, root rot, crown rot and common and pepper leaf spot. Choosing new varieties that offer better disease resistance will help in prevention of these diseases occurring and therefore increases overall yields and persistence of your lucerne stand.
10. Treat for pests as soon as they appear
Lucerne pests include red legged earthmite (RLEM), lucerne flea and aphids which can quickly kill seedlings. Spray with registered insecticides as soon as they appear. Certain insecticides can be tank mixed with glyphosate prior to sowing to protect the initial few weeks of a lucerne crop.
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.
11. Manage for persistence
The persistence of a stand of lucerne will depend largely on the way it is managed. Winter dormant varieties (because of their lower crown) are generally more suited to grazing than winter active types. When grazing winter active varieties, care must be taken not to eat out the crown. Strict rotational grazing must be employed and a recovery period must be allowed for the lucerne to regrow prior to future grazing.
It is generally accepted the optimum management strategy for maximum productivity and persistence of lucerne in its first year is to have the stand at least 20 cm high and preferably 10% flowering before first cut or grazing. This allows adequate root reserves to be laid down for strong regrowth after cutting. Another good indication on when to first cut or graze young stands (or old stands) is to look for the appearance of 2 cm long new shoots (secondary regrowth) from the crown of the plant. This may be a more reliable indicator than the 10% flowering yardstick.
Lucerne is an ideal crop for many farmers and by following the 11 tips identified above will help farmers achieve a productive and profitable lucerne stand.