Lucerne Seeds

Lucerne is used as a long-term pasture for grazing and/or hay production, a short-term stand in cropping rotations, or as the legume component of mixed pastures. Being a legume, lucerne has the ability to fix atmospheric nitrogen, providing nitrogen for its own growth, to companion species or increasing soil nitrogen levels for subsequent crops.

Lucerne can utilise more rainfall than other species and dry the soil profile with a large taproot that can easily grow to three metres depth or more to access deep soil
moisture. This taproot also acts as an energy store for the plant making established lucerne very hardy. Lucerne has a moderate tolerance of salinity, which combined with its ability to dry the soil profile and lower the water table makes it a useful tool in managing soil salinity, particularly as an option in recharge areas.

The main limitations to lucerne’s use in Australia are soil waterlogging and high soil aluminum (Al³⁺) levels which inhibit root development and cause difficulties with establishment. Aluminium is highly correlated with pH and adjusting to or selecting sites with a pH of 5.4 (CaCl₂) is recommended. Sardi 7 series 2 will has been tested to produce reliably to a pH of 5.0.

Modern lucerne varieties are now available that have been developed in Australia under grazing for Australian conditions, with adequate resistance to key pests and diseases verified in Australia, ensuring they have the best chance of performing in our unique environment. Selection of the right lucerne variety is a crucial component of establishing a successful, productive and profitable lucerne stand.

Yield Potential and Fertility

Lucerne can produce a wide range of yields potentially ranging up to 10 – 25 tonnes DM/ha/yr. Phosphorus (P) and potassium (K) maintenance are essential, especially in a cut and carry operation where high levels of K (20 – 30 kg/t of DM) leave the paddock. For each 10t DM this also equates to 200 kg calcium (Ca), and when compared to 360 kg Ca in one tonne of limestone lime, indicating that on average 1t lime/ha every two years or so is required to maintain calcium nutrition as well as to help manage pH and aluminium.

Fertiliser is generally applied at intervals that suit the grower. Ideally this is programmed with each harvest (cut), but may be only once or twice a year. Molybdenum (Mo) is essential for plant growth and healthy nitrogen fixation. Consider applying 150 – 200 g/ha of molybdate or equivalent every 4 – 5 years where levels are typically low or where Mo is neglected from other parts of the system or rotation. Mo should always be applied with copper included in the program to help avoid animal health issues.

Crop removals: For each tonne of dry matter (DM) removed, the following nutrients are lost.

Cutting for Fodder Production

Harvesting lucerne for silage or hay should to be done at or a bit before 10% flowering, but note the height of new shoots at the base of the crop, and ensure that they are not damaged as they will be the next crop (best method of assessing cutting timing). Conditioner rollers are useful for quick drying. Double conditioning has been used. Re-cutting depends on seasonality, climate and dormancy.

Root Reserves

Allowing the crop to have at least one good flowering per year will aid replenishment of root reserves.
Ideally, use the appearance of new shoots at the base of the plant (approximately 10% flowering) to determine cutting/grazing timing – this will help topup root reserves during the year. This will ideally take place in mid-late autumn, as the plant will then contain good reserves to come away the following spring. The feed reserve built up over the rest period in autumn can be fed off as valuable early winter feed, prior to winter cleaning herbicide sprays.

Lucerne as a Pasture Mix

When sowing lucerne as a pasture mix, establish it with a low seedling vigour grass such as a winter active fescue, phalaris or a winter cocksfoot. Sowing with
ryegrass is rarely successful as modern ryegrasses have too much seedling vigour. It may be better to establish the lucerne first and introduce the companion varieties a season or two later, especially for producers unfamiliar with lucerne management. In extensive sheep grazing pastures, lucerne mixtures with sub-clover are popular as they aid erosion control in the lucerne inter-row and compliment the feed availability in the cooler months. If lucerne is to be included in a pasture mix, it is
recommended to retain robust sowing rate of the lucerne component to help ensure satisfactory establishment.

Under-sowing in Cereals

If under-sowing lucerne with a cereal grain crop, reduce the cereal rate back to around 50% to ensure a good lucerne stand is maintained. Expect lower cereal yields as a consequence.

Grazing Management & Grazing Tolerance

Ideal management of grazing would require a short, sharp grazing period of 2 – 3 days, followed by a rest and regrowth period of around 20 – 25 days over summer and longer over winter, with the stock introduced at around 5 – 10% flowering and the crop evenly defoliated. This, however, may not always be achievable due to various factors, but the principles borne in mind and grazing management adopted which tends towards this regime. In practice, lucerne will handle limited set-stocking for a period of weeks or a month or two. If periods of set-stocking or lax rotational grazing are likely to occur, there are a number of key things to bear in mind and include in the program.

Stock will tend to graze the leaves in preference to the stems. This may lead to excessive protein intake leading to issues such as red-gut, and potentially bloat. In terms of stock performance, lax grazing may see an initial increase in performance, then the production levels fall off as stock are left with a high proportion of stalks on offer. Try to adopt a system where the entire stalk is consumed along with the leaves. Stock density will be important. Modern cultivars selected for high leaf:stem ratio such as the SARDI range will also help. Consumption of the leaf and stalk together is a relatively balanced diet for ME, CP and fibre.

Growers should select lucerne cultivars developed for and selected under grazing in Australia. These have been screened and re-selected under protocols which provide such features as a low and broad crown, high number of auxiliary buds, and have been subjected to very high grazing pressure for extended periods. The Australian program run by SARDI and Barenbrug has these features built in as breeding objectives, which result in the high resilience to grazing of all varieties in the range. The features that confer grazing tolerance also offer good attributes for high quality fodder production. The broad crown with many buds will allow for the development of a high number of finer stems, which then offers hay and silage with pleasing feed quality features.

Winter Dormant Lucerne

Winter dormant lucernes grow actively through spring and summer and into early autumn when growth rates steeply decline. They can be very productive under high rainfall or irrigation, but less productive than winter active types in regions with winter dominant rainfall below 650mm. These varieties generally have a low prostrate crown giving good grazing tolerance and improving persistence. They also have a high leaf to stem ratio which can contribute to higher feed and hay quality. Winter dormant lucernes are not suited to late autumn/early winter sowing.

Winter dormant lucernes are best suited to irrigated hay production or long-term pasture situations in colder, wetter environments, where rainfall continues into late
spring and early summer, and winter grazing is provided by other pastures or crops.

Winter Active Lucerne

Winter active lucernes have an intermediate crown size and can provide excellent grazing tolerance and persistence. This category are the most versatile and therefore the most popular lucerne type, giving good growth into late autumn and holding their quality longer than highly winter active varieties.

Winter active varieties are best suited to medium term mixed farming situations that require grazing tolerance and the ability to make good quality hay. They are well suited to irrigated or dryland production and are useful as a pure stand or as a perennial legume component in pasture blends for regions with 450 – 650mm winter
dominant rainfall.

These lucernes also make excellent permanent summer forage crops in the high rainfall dairy regions because they provide feed over a longer period than summer brassicas without the same insect challenges.

Highly Winter Active Lucerne

Highly winter active lucernes are bred for late autumn / early winter sowing and have excellent seedling vigour for under-sowing in cereals. Some of the newer
Australian bred material in this group has increased grazing tolerance because it was selected from and developed for these broadacre grazing systems.

These lucernes have a more upright crown and erectgrowth habit, they are well suited to a 2 – 4 year cropping rotation system in the 300 – 500mm rainfall zones. They provide maximum growth potential in winter dominant growing-season rainfall areas, and the highest fodder yield potential should growing and harvesting conditions allow. In general, highly winter active lucernes do not persist as well as more dormant types due to less resilience to tight grazing or machinery damage to the smaller, more up-right crown of the plant.