The arrival of spring marks the beginning of the agricultural cycle, with crops emerging from their winter dormancy and preparing for the crucial flowering process. Pome, stone and nut fruit trees are the first to awaken, while crops such as olives – characteristic of the Mediterranean climate – show a later flowering, generally in April and May. In contrast, species such as citrus or avocado, adapted to warm climates, do not require an accumulation of cold hours to initiate their cycle.

Factors influencing flowering

Several factors are involved in the flowering process, some of which can be mitigated by appropriate nutrition and biostimulation strategies. The accumulation of chilling hours is essential for the regulation of the biological cycle and flower development. In addition, the previous year’s load and flowering level may affect current production due to energy and nutritional depletion. Frost, heat stress and rainfall during flowering can also have a significant impact on production by causing flower abortion or premature fruit drop.

Essential aspects of nutrition

Maintaining a good sanitary and nutritional status of the crop is essential for successful flowering and good fruit development. Both post-harvest fertilization and flowering treatments are equally important.

The first of these should be considered a mandatory practice, as it contributes to restore the necessary nutritional levels during the winter period. As well as in the activation of the crop at the beginning of spring. The second aspect, which is the focus of this article, highlights the importance of macronutrients such as Nitrogen, Phosphorus and Calcium. As well as micronutrients such as Boron, Molybdenum and Zinc.

Focusing on this aspect, a correct fertilization plan before and during flowering, as well as during fruit set and fruit fattening is essential to guarantee the harvest per tree.

• Nitrogen contributes to increase the longevity of the ovules and thus to lengthen the pollination period.
• Phosphorus is involved in energy transfer and has a direct effect on flowering. At the same time, it increases the fruiting capacity, its intensity and the fruit set level.
• Calcium positively influences pollen grain germination by accelerating pollen tube growth.
• Boron is essential in the processes of cell division and growth. In addition to being key to pollen grain viability and regulation of hormone levels.
• The importance of Molybdenum lies in the fact that it plays a role in nitrogen fixation, being a key component in two of the enzymes that transform nitrate to nitrite and then to ammonia. In addition, Molybdenum has direct activity on pollination and fertilization of flowers.
• Zinc, on the other hand, is directly involved in the synthesis of enzymes, especially auxin synthesis. It is responsible for the growth and elongation of internodes and the development of chloroplasts.

Biostimulation, the essential companion

But nutrition without biostimulation is meaningless, since fruit trees have other complementary needs that can only be met by biostimulants. These metabolic needs are palpable during the flowering period, when the plant’s energy requirements are very high and the stress level is very high. Both biotic and abiotic stresses to which it is exposed can negatively affect fruit set, development and ripening. This is why it is essential to implement a strategy that combines biostimulation with balanced nutrition, capable of supporting the crop during this period of high energy and nutritional demand.

It is highly recommended the application of amino acids with a complete aminogram profile in which glycine, glutamic acid, alanine and proline predominate. All this to guarantee an energy supply in accordance with the demands of the flowering process. In the same way, products based on algae extracts, which are characterized by a high content of phytohormones, mannitol and arginic acid, should also be taken into consideration. One of its main functions is to mobilize sap to all parts of the plant, helping to mitigate stress caused by adverse climatic conditions and favoring fruit set and reducing premature fruit drop.

Achieving optimal fruit set after flowering, taking into account the vicissitudes that the crop has to face, and above all ensuring a successful harvest, is possible. We only need to know their needs and requirements, fertilize with appropriate products and incorporate biostimulation into our strategies to achieve the best results.