Silaging lucerne

You can make baled or clamp silage with lucerne. With our weather conditions, high humidity and the low sugar content of lucerne can make it difficult to ensile. Also, lucerne is high in protein and calcium, which will buffer any changes in pH in the clamp/bale.

In the first year of the crop, you can harvest one or two cuts. After this, however, the crop will be suitable for cutting four to five times a year, typically at five-week intervals.

Typically, you can harvest lucerne from mid-May onwards (depending on location). The first two cuts are often the highest yielding.

The proportion of total yield from lucerne cuts

Source: Sheldrick et al. 1995

Deciding on the best time to cut can be a compromise between yield, quality and crop persistence. While the protein content of lucerne is greatest at the pre-bud stage, it is believed that routine cutting at this time shortens the lifespan of the crop.

Herbage harvested at full bloom will have a higher proportion of stem. As the crop flowers, the stems become more fibrous and the feeding quality of the forage decreases. Most growers choose to harvest the crop at the point of flower (10–30% flowers open) to balance quality and yield and to ensure there is adequate root development.

To encourage persistency, some growers opt to harvest one flowered crop per year. Work from New Zealand, where research is based around grazing the crop rather than cutting, supports this approach. However, French growers do not do this, because they find the subsequent cut to be of lower quality.

Regrowth of new shoots can also help determine optimum time for cutting. Harvesting when new shoots are visible will ensure good regrowth. However, shoots should be short enough to avoid damaging these with the mower.

Redrawn. Original source: Rural Industries Research and Development Corporation (2012)

• Minimum cutting height of 7cm to avoid damage to the crown of the plant. This will also allow good airflow under each swathe, which will help dry the crop
• Wilt the crop to a minimum DM of 30% (40‒50% if baling) to concentrate the sugar content, as direct cut is high in moisture and often too low in sugar
• Roller-type mower conditioners that cut and condition the lucerne by crimping or crushing the stem are preferable to speed up the rate of moisture loss from the stem without extensive damage to the leaf

Lucerne/grass mixtures are thought to be easier to ensile because of the higher grass sugar content.

Because the leaf dries out quicker than the stem of the plant, over-wilting or extensive handling can result in large amounts of leaf shatter.

Raking the crop before the dew has evaporated and reducing tractor speed will help reduce leaf losses.

Using an additive is advisable when ensiling lucerne. Seek advice from the local merchant or supplier.