Field selection and preparation for growing lucerne

In this section of the growing and feeding lucerne series, we look at factors to consider when selecting a variety and preparing a seedbed.

Lucerne will grow on a variety of fertile free-draining sites and soil types. It does not do well in waterlogged soils because the taproot can rot, meaning it may not be suitable for areas with high rainfall and heavy clay soils.

It has a huge requirement for calcium, so soils that are naturally at pH 6 or higher are ideal. It can cope with alkaline soils up to pH 8.5.

Soils at pH 5.5 or below will establish poorly and have a reduced ability to fix nitrogen from the atmosphere in the nodules.

Lucerne can do well in conventional or organic systems. There needs to be five to six years between crops.

Watch the video for advice on how to establish lucerne and the advantages that research by Harper Adams University has seen from growing the crop.

Preparation

Due its potentially extensive root structure, you must fix soil structure problems before planting.

Make sure the seedbed is clean because slow lucerne establishment can give weeds a chance to dominate.

Cutting lucerne removes much of the soil’s nutrients. For every tonne of dry matter removed from the field, these quantities of nutrients are removed:

  • kg of phosphate
  • 30 kg of potash
  • 30 kg of calcium

This means that growing lucerne on soils with good phosphorus (P) and potassium (K) indices (2 or more) and high pH will reduce the fertiliser or lime requirements in the short term.

Muck and slurries can be used to boost phosphate and potash levels; however, no more than 30 kg N/ha should be applied. Well-rotted and old farmyard manure has lower N levels, so may be useful.

Magnesium, molybdenum and boron are required during establishment. It is useful to carry out a full trace element soil test before sowing to determine requirements.

How to select a variety

The most important characteristic to consider when selecting varieties is dormancy. This is a measure of the winter hardiness of a variety and exists on a scale of 1–12, with 1 being very dormant in winter and 12 having virtually no winter dormancy.

There are two dominant types of lucerne grown in Europe: Provence and Flemish.

Variety type

Pros

Cons

Provence (Southern types)

Long growing season

Lack winter hardiness

Withstand frequent cutting regimes

Less suited to UK conditions

Drought-tolerant

 

Flemish (Northern types)

More cold-tolerant

Less drought-hardy

Better suited to UK conditions

Poor adaptation to frequent cutting

Varieties with a high dormancy score tend to be more productive, with more vigorous seedlings and faster recovery after cutting. Be aware that the quality of these varieties reduces considerably as they become more mature.

In contrast, winter dormant varieties tend to have less vigorous seedlings, but display excellent persistency.

For UK conditions, to achieve three to four cuts per year, a dormancy rating of 4-5 is optimal.

Provence types will have a dormancy rating of 6–8, while Flemish types are likely to have a rating between 2 and 6.

In addition to dormancy, information on other characteristics, including protein content, herbage yield, pest and disease resistance, can be found by visiting the descriptive list in the Recommended grass and clover merchants’ guide. This list includes a limited number of varieties and not all those available in the UK. One possible source of information is the French Recommended List, which includes approximately 30 varieties of lucerne.

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