El citrus cultivation, especially the orange, is a great Spanish reference, having its main bases in the area of Huelva, Seville and the Valencian CommunityThere are many scientific studies that teach us how to properly fertilize plants to achieve good juice quality, fruit size, and number.
Figure 1. Flowering and fruit set in citrus fruits.
La phase of fflowering and fruit setting It is critical for many varieties that have production problems. Therefore, the correct application of fertilizers before and during flowering and during fruit set of fruit is essential to maintain an adequate number of fruits per tree.
Los microelements They play an essential role in the flowering of citrus fruits. Among them, and due to their level of consumption, the most important are iron, zinc y manganese. They are related to the phase of cuajado and number of fruits, and its deficiency in the plant causes physiological disorders and reduces the number of fruits per tree.
El zinc It intervenes directly in the synthesis of some amino acids, although its most relevant function in plants is activation of numerous enzymes, highlighting the auxin synthesis (indoleacetic acid). It is therefore involved in the production of growth regulators responsible for the internode elongation and chloroplast development. Your deficiency reduced significantly the growth and productive potential.
El manganese is related to photosynthesis, the efficient use of nitrogen, protein metabolism and enzyme activationIt acts on carbohydrate and fatty acid metabolism, phosphorylation reactions, and nucleic acid (DNA and RNA) formation. It also intervenes in water photolysis during photosynthesis, as well as in sucrose synthesis in plants and protein formation. Severe and persistent manganese deficiencies reduce growth, productivity, harming the general development of the plants.
Figure 2. Zinc (left) and manganese (right) deficiencies in citrus leaves.
During the flower formation process, the manganese intervenes in the pollen germination and pollen tube growth, while zinc promotes pollen formation and viability. It is therefore essential to maintain adequate nutrition of these two nutrients to ensure proper and viable flowering and obtain a sufficient and quality harvest.
El fruit setting and initial development depends, among other factors, on the competition effects established between the number of flowers in development. In most cultivated varieties, the fruit set deficit only occurs when the plant it blooms a lot However, it is also possible to find reduced yields when the plant flowers very little. In the first case, it is unable to nourish all the ovaries that begin to develop, and most of them detach from the tree, significantly reducing the yield. In the second, the reduction in the number of flowers is always related to a very high number of fruits harvested (alternating crops) (Moss,1971); the action of these can be through a nutritional effect, reducing the accumulation of reserves prior to floral differentiation, or through a flowering inhibition caused by gibberellin synthesis which takes place in the fruits (Bellato et al., 1998).
Figure 3. Diagram of crop alternation in citrus fruits.
It turns out to be a lot More frequently the problem caused by excess of flowersThis occurs as a consequence of reduced harvestsThe absence of fruit is the cause of a lack of flowering control, and the excess of flowers results in a reduction in the yield that restarts the cycle. In these cases, the intensity of competition between developing flowers is responsible for the decrease in the number of those that started developing, as well as the reduced final fruit size.
Figure 4. Diagram of the lack of continuous production caused by excess flowers in citrus fruits.
This effect of flowering intensity on fruit set is general for all species and varieties and for all climatic conditions. Experiments conducted jointly with Tangor 'Ellendale' in Spain and Uruguay indicate a decrease in the percentage of set flowers as flowering becomes more intense (Gravina et al., 1996), regardless of the cultivation area.
To avoid reaching flowering intensities so high that they compromise setting and significantly reduce the harvest, hormonal treatments based on the application of acid gibberellic (as a flowering inhibition factor) (Agustí, M. et al., 2003), or some kind of biostimulants that provide the plant with metabolites capable of activating the synthesis of promoting and inhibitory factors in balance enough to achieve good flowering and set.
From the Cultifort Technical Department we want to offer a recommendation to help cover the nutritional and metabolic needs required during flowering and fruit set of citrus fruits.
It is a liquid formulation with high richness in zinc (8,7% w/v) and manganese (10,2% w/v) chelated with EDTA, polycarboxylic acids (2,9% w/v) and reducing sugars* (2,9% w/v).
It is recommended to apply it during the spring and summer buds or during the last weeks of ripening to accentuate the color of the fruits.
Product certified for use in ecological agriculture (CAAE).
BVC EVOLUTION (Formerly BVC 2021)
Liquid biostimulant for foliar application and with a great synergistic effect between amino acids (2,4% w/v) and complejo alginic en emulsion (24% w/v), with nitrogen (12% w/v) (ureic, ammoniacal, nitric and organic), potassium (1,2% w/v) and reducing sugars* (12% w/v).
BVC EVOLUTION promotes the synthesis of proteins and carbohydrates and promotes the beginning of the physiological activity of the plant, controls problems of alternation of production, improve the quality of the fruits y advances maturationThe alginic complex emulsion included in its formula contains Mineral salts, Vitamins, essential oils, proteins y natural phytohormones (cytokinins, auxins, and gibberellins), in addition to other compounds such as betaines, polyamines and oligosaccharides, which increase the resistance from the plant in front of low temperatures y Adverse weather conditions. Likewise, BVC 2021 acts on apical dominance, exerts a Multifactorial control of flowering, delays leaf senescence, participate in the fruit ripening process and can influence the coloration of the same due to their carotenoid content.
REFERENCES
Agustí M., Martínez A., Mesejo C., Juan M., Almela V., 2003. Fruit Set and Development in Citrus Fruits. Technical Outreach Series. Department of Agriculture, Fisheries and Food, Generalitat Valenciana.
Bellato M., Castro PRC. And Agustí M.,1998. Alternância de produção em citros. Laranja, 19:293-304.
Gravina A., Rabiza H., Juan M., Almela V. and Agustí M., 1996. Flowering-fruiting interrelationships in 'Ellendale' tangor under the growing conditions of Spain and Uruguay. Proc. Int. Soc. Citriculture, 2: 1081-1085.
Moss GI., 1971. Effect of fruit on flowering in relation to biennial bearing in sweet orange (Citrus sinensis). J. Hort Sci., 46: 177-184.