by Katerina-Glafki Apostolopoulou
Il boron (B) is a essential microelement for the healthy growth of plants, especially olive treesIts application directly impacts olive production and quality, as it improves calcium mobility, flower development, and fruit set. It reduces fruit drop and increases fruit size and weight, improving yield quality.
La its deficiency can cause serious problems in the flowering and fruiting of trees, influencing the final yield of the olive grove. Although its use among olive growers is more widespread in spring, during the winter period, when the trees are dormant, Correct application of boron can improve fruit production and quality, preparing the trees for the new production season.
Application through soil
In olive groves, boron is usually applied via borax, a crystalline fertilizer. Borax is applied during the rainy season, to ensure easy dissolution in the soil and better absorption by tree roots. The recommended application dose is 300 g per tree every 2-3 years, although studies conducted on olive groves in Türkiye have shown that an annual application of 250 g may be more effective in increasing the production and quality of the fruits.
Foliar application
The Foliar application of boron from December to February appears to have positive effects on flowering and fruitingIn particular, foliar application of boron in January has proven to be particularly effective in increasing production. Studies conducted on olive groves in Egypt have shown that Foliar application of boron in January increased production by 200% compared to trees that did not receive such application.. The reason why January and February are the most suitable months for applying boron is linked to the beginning of the differentiation of flower buds in the olive tree, a process fundamental for successful flowering and fruiting.
Foliar application of boron, especially if combined with other nutrients such as nitrogen and magnesium, produces positive results in the differentiation of flower buds and the greening of foliage, improving the overall growth of trees and their productivity.
Il boron not only influences flowering, but also has a significant impact on fruit qualityIn a 2015 study, foliar application of boron to an olive grove in January led to increased production, as well as better-quality fruit with a higher oil content.
Olive growers should carefully monitor their trees' needs through soil and leaf analyses, always consulting a specialized agronomist. Especially in areas with severe boron deficiency, winter and spring applications can yield spectacular results in terms of fruit set and overall grove yield. Specifically, trees treated with boron in both periods showed up to 3,5 times higher fruit set (7%) compared to those treated only in spring (2%).
Sources
Hegazi, E. S., Motaium, R. A., Yehia, T. A., & Hashim, M. E. (2015). Effect of foliar application of boron on vegetative growth, flowering, fruit set, yield and fruit quality of olive trees (Olea europaea L.). Journal of Horticultural Science & Ornamental Plants, 7(1), 48-55.
Gul, G., Khattak, A. M., Shah, M., Amin, N. U., Bakht, T., Iqbal, J., & Shah, S. (2017). Effect of different boron concentrations and application times on olive production (Olea europaea L.). Sci. Int. (Lahore), 29(5), 1155-1159.
