IN the UK, lucerne can be clamped or baled - hay is rarely made due to the fragility of the leaf.
Conservation can be difficult due to the high humidity and low sugar content of the crop, so good management is key to high quality forage. The high protein and calcium levels will buffer any changes in pH in the clamp/bale.
Cutting is usually from mid-May, depending on location and only one or two cuts will be taken in the establishment year. Do not cut too early in the establishment year to allow optimum tap root development. Normally, first cut should be allowed to reach 25-50 per cent flowering.
Once established, lucerne can be harvested four to five times per year, usually at five-week intervals - these intervals are crucial to manage feed quality and allow nutrients to build up between cuts. It is critical for long-term survival to leave the crop to build up root reserves for six weeks in autumn after a late August/early September cut. This cover can be harvested in mid-October, or grazed with sheep.
For optimum yield and quality, cut at the early flowering stage. In cold seasons, flowering maybe delayed, so cut when the crop is in bud stage. Later in the season it will flower more readily. Cutting intervals will be affected by hot and dry weather, so it is crucial to keep checking the crop.
Ideally mow with a crimper conditioner (not a flail) and leave in as wide a row as is practical for the forage harvester or baler. The aim is to cut the stem without bre-aking the delicate leaves. ‘Gentle’ rowing up is recommended.
A minimum cutting height of 10cm (4in) will avoid damage to the re-growing buds on its crown. The bottom 10cm of stem will have a very low D-value anyway and the higher stubble will allow air to pass through the newly-cut grass to aid drying.
The crop should be wilted for 24-36 hours to 35 per cent DM (minimum of 30 per cent) - low dry matter lucerne ensiles badly.
If baling silage, do not allow the crop to get too stemmy as it may puncture the wrap. Select varieties with finer stems and cut at the right time.
A minimum of six wraps is advisable, eight is preferable –the extra cost of about 75 pence per bale will be worth it.
Lucerne is low in sugar, usually about 30 per cent, so the use of additives is recommended. Often specific inoculants are used and at a higher rate than for other forages. Clamp in thin layers with plenty of rolling.