Insights from increasing experience with lucerne

The key learning points listed

• Ensure a solid foundation (soil). This always applies, but especially for the cultivation of legumes. The correct pH and the availability of calcium are important, among other factors. Grow lucerne on land with low weed pressure, because control options are limited and weeds spread quickly.
• Sow at the right moment. This means, among other things, not sowing after 15 September in autumn. The best period is the second half of August, also in relation to weed pressure. This fits well in a rotation with grain or after maize in the case of spring sowing and a cover crop with grain. Grass as a preceding crop is discouraged and is not permitted under the eco‑scheme. This relates to mineralisation after ploughing, which reduces nitrogen fixation by lucerne.
• Prevent wheel damage. Unlike grass, lucerne is sensitive to damage caused by tractor tracks. This leads to plant loss and bare patches with all associated disadvantages. The crop does not recover, and overseeding is not possible. In practice, headlands are often sown with grass or a grass–lucerne mixture to limit damage. For the same reason, a mineral fertiliser application may be more suitable than slurry. In summer and/or autumn, a potash fertiliser is necessary if slurry is not used.
• Determine the right moment for renewal. The crop lasts on average three years, but there are examples of two years and also of five years. A guideline is at least 175 plants per square metre in the second year. If there are fewer than 430 stems per square metre, renewal is recommended.
• Consider the need for a cover crop. Usually this is not necessary. An advantage is slightly faster ground cover, lower weed pressure and somewhat higher yield of the first cut. However, it carries the risk of reducing lucerne yield. On fields with high weed pressure it can be an option. In that case, it is preferable to mix 5 kg of an annual clover mix (Protafix) with 25 kg lucerne.
• Conserving lucerne after harvest requires attention. The protein‑rich product must be chopped properly and compacted during ensiling. Using a preservative is essentially a must. Farms that ensiled lucerne between layers of grass achieved good results on average last year.
• Make use of the advantages in the ration. These include the high levels of protein and structural fibre. Lucerne fits best in rations with a high proportion of maize silage. The compound β‑carotene is known for its positive effect on fertility.