1. Precursor, place in crop rotation

Alfalfa can return to the same field no earlier than the number of years it has been grown there.

Fields to be sown with alfalfa must not have had legumes for at least 5 years.

After alfalfa, it is best to sow swidden crops, especially maize. Cereals with a flush surface should only be put on weak soils after alfalfa.

2. Soils

Alfalfa can be grown on all soil types provided they are deep and structural to allow root development. The soil reaction should be neutral. It does not tolerate waterlogging, acidification, excessively compacted or stony soils.

3. Tillage

Alfalfa will be in one place for several years, so it is best to till the soil 25-30 cm deep. There should be depth for root development, but a fine triangular seedbed on top. Competition from weeds in the initial development should also be avoided, so the last pre-sowing tillage is carried out immediately before or at the same time as sowing.

The main tillage may vary according to farm tradition and soil characteristics, but must be carried out in autumn. It is important to have a loose, structured, settled and clean soil bed before sowing.

4. Sowing

a/ depth of sowing - about 2 cm - 1 to 3 cm maximum. Light dry soil - 3 cm, heavy and cold soil - 1-1,5 cm.

b/ row spacing - best results are obtained when sowing in cohesive rows - 10-15 cm (usually 12.5 cm).

c/ sowing density - the highest yields per mass have been found at 2,4 kg/dca, but since germination, which is low in alfalfa, has to be compensated for, in practice the sowing rate varies between 2,5-3 kg/dca.

Note: Where alfalfa is an investment for industrial production on large areas, I do not recommend experimenting with sowing under cover in mixture with other crops or limiting this to small trials.

d/ decontamination - against soil-borne pathogens causing a range of diseases, it is advisable to treat the seed with appropriate fungicides. Care should be taken not to waterlog the seed during treatment so that it is properly topped at sowing.

e/ sowing period - theoretically alfalfa can be sown from 10 March to 10 September. The average daily air temperature should be about 10 degrees. If the spring is cold and wet, sowing too early will result in stunted initial development. In early spring the day is still short and the root cannot develop properly.

Late planting in turn leads to drought risks, which can, however, be compensated for in subsequent seasons.

Sprouts and young plants can withstand down to -7 degrees. But if we have late frosts of -1 degrees and already more developed plants - their vegetation peak will perish.

BECAUSE OF THESE REASONS I recommend sowing after March 15 for southern Bulgaria, after March 25 for northern Bulgaria, after April 1 for high fields.

f/ inoculants- it is possible to use inoculant seeds to stimulate the activity of tuber bacteria, but they are not a determining factor, and in alfalfa in general their effect is questionable.

f/ raining - mandatory after sowing (adapted to soil structure and moisture).

5. Fertilizing

Phosphorus is mandatory for yield formation, it is best to apply it sparingly before deep tillage, the norm for the long term is about 25 kg P2O5. If less is applied, about 6-8 kg/dca will be added annually.

Although it should not be overloaded with Nitrogen, it is still necessary to pre-sow 3-6 kg N/dca, this will ensure the initial development and nutrition of the crop. More should not be fertilised as it will inhibit the formation of tuber bacteria.

Alfalfa will then be fertilised with nitrogen annually, before the start of the growing season. There are different trials and theories here, further I would recommend trying 2 schemes on certain areas and making your own choice.

a/ Standard - a moderate dose at the beginning of the growing season (5-6 kg/dca of N)

b/ Strike high at the beginning of the growing season - 15-18 kg/dca of active ingredient)

The second option has the ability to overcome the tuber suppression effect and increase both yield and protein, but it also depends on conditions, I would recommend trying it on a small area. It only applies to old alfalfa.

Research suggests that mineral nitrogen application during the growing season has no economic impact on yield. I recommend very small amounts of organic amino acids for vitalization be added when going in with an insecticide or other occasion with the sprayer.

Potassium - alfalfa exports large amounts of potassium with the produce. It should be applied in a phosphorus supply at a high rate. Since this is not practiced, I always recommend a spring time foliar application of potassium for health and drought tolerance. It can also be by granulates. Magnesium is also important. Magnesium for young alfalfa especially will stimulate root development. Our soils are relatively well stocked with potassium, but magnesium is increasingly lacking.

A very important element for alfalfa is Calcium - it also increases the protein content. If the soil reaction is below 6 or at the limit, it is good to apply extra.

Of the trace elements, Molybdenum also responds well - as a seed treatment or vegetatively.

If the cut is left to seed, an application of Boron at the start of flowering is recommended.

6. Weed control

Registrations are few. Please specifically for herbicides consult representatives of the respective importing companies.

Pulsar is most widely used for both young and old alfalfa. There is registration only in young. 120 ml/dca. BASF, SYNGENTA.

Senkor - BAYER - for old while still dormant in winter, for young after sowing before emergence. 90-100 ml/dca.

Basagran - BASF - had registration many years in alfalfa. 200-250 mc/dca for young alfalfa among broadleaves in 2-4 leaf.

A more recent generation is the combination herbicide Corum at 125 ml/dca - a vegetative herbicide and has registration in old alfalfa against both broadleaf and cereal weeds. BASF.

Eclipse - ADAMA, applied in autumn or winter when there is no vegetation. 50-75 g/dca.

Against cereal registration have Dual Gold 150 ml/dca and Stratos/Focus ultra.

7. Fighting diseases

Of the diseases, ascochyta, rusts, mildews, verticillium wilt, bacterioses, viruses, etc. are the most common. Fungicides with the active ingredient azoxystrobin are effective against some typical fungal diseases, tebuconazole against others.

In general, well cared for and supplied with trace elements, alfalfa resists and overcomes the attacks of pathogens.

Plant health is stimulated by the introduction of copper and sulphur into the crop.

Consider what the production requirements are if it is to be exported.

 
8. Pest control

Alfalfa is mainly attacked by leafhoppers, ladybirds, weevils and sometimes aphids.

Other polyphagous pests are also found.

There is a wide choice of insecticides, but it is important to change the active substances.

MONITOR THE QUARANTINE PERIOD - KEEP IT SHORTER IF POSSIBLE SO THAT THERE ARE NO RESIDUES IN THE PRODUCE.

Treat after observation and as needed. If there is an infestation at the beginning of undergrowth development - spray, but if the infestation is when the undergrowth is almost formed, then it is better to harvest it a few days prematurely and treat the field immediately after mass removal.

 9. Harvesting

The stage matters for yield and quality.

As the above-ground mass increases, yield increases but protein decreases at the expense of cellulose. In short, the plants get rougher.

Protein content is highest in budding. Thereafter, protein decreases by about 0.3% per day until flowering. Vitamins, digestibility and nutritional value decrease. A compromise for optimum yield/quality ratio is to harvest at the beginning of flowering.

Cutting height is important to preserve crop longevity. It is correct to cut at 5-6 cm. The last cut in the autumn - at 7-8 cm. The first cut of young alfalfa is also made at this height.

The last mowing, depending on the weather, should give the alfalfa a rosette of more than 10 cm. This is from the end of September for the northern and high parts of Bulgaria until mid-October in the southern plains.

Ing. Evelina Marinova

January, 2020