“The nutritional deficiencies most observed in citrus orchards occur as a result of low levels of nitrogen, phosphorus, potassium and calcium…”
Maíra Ferreira de Melo Rossi is a Ph.D. student in plant health, with a M.Sc. degree in applied botany from the Federal University of Lavras (UFLA), and she is an agronomist from the Federal University of São Carlos.
AgriBrasilis – Is liming more important in the case of citrus? Why?
Maíra Rossi – Liming is very important for citrus plants due to their high calcium requirement. This step is essential at the time of planting, as this is the best time to correct the acidity, before establishing the orchard. In orchards that are being established, it is recommended to apply 70% of the lime dose under the projection of the crowns and the remainder between the rows.
AgriBrasilis – What are the most common nutritional deficiencies in orchards and what are the consequences of a lack of nutrients?
Maíra Rossi – The most common nutritional deficiencies observed in citrus orchards occur as a result of low levels of nitrogen, phosphorus, potassium and calcium. Calcium is the element most required in citrus: therefore, in foliar analyzes calcium is the nutrient found in the highest concentration, unlike other crops.
As for micronutrients, the most commonly observed symptoms occur due to boron, zinc and manganese deficiency. In addition to these, during the orchard formation phase, copper deficiency may be observed, due to the lower frequency of applications of copper fungicides at this stage.
Inadequate nutrition, from the implantation (establishment) phase to production can compromise the development of seedlings and the orchard yields. In this context, among the main advances in citrus farming, we can mention the gain in productivity with the greater density of plants associated with irrigation and/or fertigation, which allows for greater efficiency in the use of nutrients.
AgriBrasilis – Can nutritional management minimize the damage caused by diseases in citrus crops?
Maíra Rossi – Well-nourished plants in a citrus orchard may suffer less from diseases, but only an adequate nutrition does not provide protection from diseases or protect against pest attacks. A well-nourished plant may appear less injured when attacked by a pathogen, but this condition does not exempt it from suffering an infection or attack.
“Calcium is the element most required in citrus: therefore, in foliar analyzes calcium is the nutrient found in the highest concentration”
AgriBrasilis – How should citrus nutritional management be carried out to obtain high productivity and fruit quality?
Maíra Rossi – Fertilization during the production phase should be carried out between September and March, due to the greater demand for nutrients in the spring. Nutritional management aimed at fruit quality must prioritize fertilization with micronutrients, in addition to the recommendation to apply nitrogen, phosphorus and potassium.
Calcium prevents the formation of small fruits, for example. An adequate supply of potassium prevents fruit cracking. Even the soluble solids content, acidity, and amount of fruit juice are affected by the lack of nutrients. Thus, a well-nourished orchard directly reflects the quality of the fruits.
AgriBrasilis – When is the best time to fertilize citrus? What doses are recommended and why?
Maíra Rossi – Fertilization must be carried out throughout the formation of the orchards, from implementation to the fruit production phase. Based on soil analysis and the recommendation in the technical guidebook “Boletim 100”, the best dose can be determined according to the orchard’s needs.
Leaf analysis can also contribute to decision making. The doses indicated must follow current recommendations, taking into account the age of the orchard, the rootstock used, the group of varieties, such as tangerines, lemons, or oranges, and the expected yields.