Harvesting lucerne


Harvesting lucerne

Although lucerne can be grazed, the use of the crop as silage creates the initial interest. Lucerne is very well-suited for making silage or hay, but even for zero-grazing systems (fresh feeding). The moment when to cut lucerne is a difficult management decision. Yield and quality are very strong correlated in lucerne. From early- till full-bloom digestibility drops with 1% per day. This means harvesting in a young stage (pre-bloom) gives high quality but low yield. On the other hand, cutting at a mature stage (full-bloom) gives high yield but low quality.

On top of that, cutting management influences stand persistency. The regrowth of lucerne is very strong depending on the availability of food reserves stored in the roots. Just at the beginning of flowering, sufficient food reserves are present for good regrowth of the crop. So continuously cutting too early lowers plant health and increases weed invasion.

Timing and planning

  • The optimal time to cut lucerne is when 5-10% of the plants are flowering (early bloom). At this moment more than half of all plant should have a new sprout coming from the crown.
  • When aimed for the maximal quality, harvest occurs in pre-bloom or late-bud stage. This will exhaust the stand too much, so if done so it’s advised to let at least one cycle in the 2nd half of the season flower. This will ensure the accumulation of sufficient root reserves.
  • For maximal yield (hay production for example), harvest can be scheduled around mid-bloom stage (50% flowering).
  • Harvest by growth stage instead of calendar, gives more consistent forage yield and quality.
  • Lucerne is susceptible to damage from traffic, so don’t cut under wet conditions.

Autumn harvest

Timing of the last harvest in autumn is an important consideration. If Flemish types (winter dormant types) are used, plants should have enough root reserves before they go dormant in the autumn. Too frequent cutting in autumn is therefore not recommended. A practical advice is to not harvest for a month (best: September) to ensure plant health. It will also be possible to cut very late in autumn and let the lucerne go dormant with bare stubble instead of having new sprouts. In case of wet conditions, it might be an option to graze the last cycle or feed as green feed.

Stubble length

  • 6 cm in pre-bloom stage.
  • 7 - 10 cm in all other stages.
  • Too low cutting damages crowns and new sprouts.

Field period and technology

Fast dehydration after cutting is necessary to retain the highest forage quality, and prevent dry matter losses. As lucerne hardly dries without sunlight, the moment of cutting should leave enough time left to get sufficient dehydration before night. There are several options to speed up drying:

Use a conditioner on the mower. This machine treats the lucerne plants smoothly, without any leaf losses. For making hay or haylage, a conditioner is always needed.

  • Wide swaths of >70% of the mower width. This allows more air and sunlight on the harvested crop. For making silage, this is usually sufficient to dry fast enough.
  • Using a regular (grass) tedder isn’t advised in lucerne, as this will increase leaf losses and thus, lower protein content. If the crop has to be raked before being chopped or baled, raking should be done with a low frequency (rpm) and high tractor driving speed.

Silage and hay

The optimal dry matter content of lucerne silage is between 30 and 40%. Usually this level can be achieved on the field within 24 hours. On sunny, hot days lucerne can even be harvested on the same day of cutting. For the best silage it is recommend to chop the crop at 30-40 mm particle length. Tight compressing in a silo is needed to remove air. A basic rule is to use one heavy loader per 15 mton dry matter silage per hour. Due to low sugar and potentially lots of free available nitrogen, it is always advised to use an inoculant when ensiling lucerne.

Lucerne is ideal for making hay or haylage bales. A longer field period is needed to achieve the right dry matter content. In this situation, it’s extremely important to treat the crop carefully, as leaves fall off easily from dried lucerne plants.

Essential during the collection of silage or bales is that heavy machines do as little harm as possible to the stand and soil. Make sure that full loads aren’t transported through the whole field, and use the same tracks if possible.

European climate zones


Europe climate map zones

Depending on the climate zones, Barenbrug offers various Lucerne products. Every product has its own features suitable for different conditions.

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