Many alfalfa cultivators face the problem of gaps in culture in the year 4-5 since its establishment, and this is associated with the physiological depletion of plants. However, things become more worrying when the density of plants in relation to the unit area is reduced from the first years after the establishment of the crop.

In the second case, the first measure taken into account is to correct the density of the plants by overseeding. But will this help in improving the culture?

Overseeding in alfalfa cultivation is inefficient for several reasons:

First of all, alfalfa is a slow-growing perennial plant in the early stages of development and this will create uneven competition with mature plants and weeds for light, water and nutrients.

Second, if the cause of this is not identified, the plants will disappear again in the overseeded areas.

Third, mature alfalfa plants produce autotoxins that reduce the development of young plants and suppress sprouting seedlings.

However, there are also situations in which the overseeding of alfalfa surfaces is successful:

• when on the surface that is being sown, the crop was established in late autumn at the end of the sowing season, and some of the seedlings were affected by frost;
• also in the case of the 1^st year of cultivation the over-sowing gave results, when the surface was flooded and the plants perished in an early stage of development;
• if the alfalfa was established on land with a high reserve of pests or diseases and the degree of emergence was considerably influenced by this.

In the case of cultivating alfalfa for fodder, we can very well overseed a low-density crop with other annual or perennial fodder plants (Sudan grass, Lolium multiflorum, Festuca pratensis, Festuca arundinacea etc.); sown in autumn or early spring, these species will be in vegetation in spring, before or together with alfalfa plants, and on the other hand they will adapt better in areas of the plot where the soil is less beneficial for alfalfa.