The olive tree expresses its productive potential only when it has a balanced and continuous supply of nutrients.
The availability of these items depends on the soil pH, from her structure, from the ability to cation exchange and water availability, today a determining factor for root absorption and nutrient mobility.
In this context, fertilization can no longer be considered a fixed intervention, but must transform itself into a “dynamic nutrition”, able to adapt to the vintage, to the available water resources and to the actual vegetative state of the olive tree.
Next to the essential macronutrients, nitrogen, phosphorus and potassium, which maintain their known optimum pH ranges for uptake (N 6–8; P 6,5–7,5; K 6,1–7,3), technical attention is now also focused onthe microelements, which more easily become limiting in the critical phases of the production cycle. Among these, the boron (pH 5,2–7), it Zinc (pH 5–7) and the Iron (pH 4,5–6,5) play a decisive role in fruit set, shoot growth and chlorophyll synthesis.
Even in the presence of adequate macronutrient levels, the deficiency of just one of these microelements can compromise yield and quality, making more careful, targeted and adaptive nutritional management essential.
The nutritional balance of the olive tree also depends on how nutrients interact with each other: some pairs, such as nitrogen and sulfur or phosphorus and zinc, mutually support each other and facilitate absorption; others, such as potassium and calcium or calcium and magnesium, counteract each other, and excessive amounts of one can reduce the availability of the other.
Needs and calendar 2026
The 2025-26 growing season, characterized by a recovery in production, will require higher inputs in irrigated olive groves.
Split nutritional calendar
February – March: nitrogen and phosphorus for vegetative recovery and flower differentiation.
April – June: boron, zinc and calcium for flowering, fruit set and reduction of fruit drop.
July – September: potassium and magnesium for fruit growth and stress resistance.
October – December: phosphorus and potassium to replenish reserves.
Dynamic nutrition requires practical choices based on three criteria: water availability, vigor and production load.
Under standard conditions, annual contributions can be directed towards:
- 90–100 kg/ha of nitrogen;
- 15–20 kg/ha of Phosphorus;
- 70–100 kg/ha of Potassium;
to be adjusted according to the year and the cultivation system.
L'nitrogen It should always be divided into at least two applications, favouring slow-release forms or fertigation in the phases of greatest demand.
Il Phosphorus it is more effective if distributed in pre-vegetative recovery, while the Potassium must accompany the enlargement of the fruit and the replenishment of reserves.
For microelements, boron e Zinc are often limiting in calcareous soils, they are Foliar treatments are recommended before flowering and after fruit set, using highly soluble formulations.
Il Calcium, essential for the consistency of the fruit and resistance to stress, can be integrated both through the roots and leaves, avoiding overlaps with potassium so as not to reduce its absorption.
Fertigation, where available, allows for the distribution of small weekly doses of N and K, maintaining constant availability in the root profile and reducing antagonisms.
Intensive systems
In intensive plantations, which present more marked root competition than traditional olive groves and require a higher supply of nitrogen and potassium, essential elements to support the greater production per hectare.
Their physiology makes them more sensitive to water imbalances and micronutrient deficiencies during critical stages of the production cycle. Nitrogen must be supplied in higher but always fractionated quantities to avoid excessive vegetative growth; potassium plays a key role in fruit quality; calcium and boron are crucial for fruit set, while magnesium, often a limiting factor in calcareous soils, directly affects photosynthetic efficiency.
Super-intensive systems
The super-intensive system is characterized by a completely different physiology. The young, low-vigour plants develop a shallow root system and have an early production cycle, requiring continuous, precise, and highly fractionated nutrition, always supplemented with irrigation. Root absorption concentrated in the top 40 cm of soil requires immediate nutrient availability; potassium requirements are high and constant; sensitivity to boron, zinc, and calcium deficiencies is accentuated; nitrogen must be administered in microdoses to avoid vegetative imbalances that would compromise mechanical harvesting.
Fertigation management must also prevent salinization and sodium and chlorine accumulation.
Conclusions
Modern orchards are highly efficient but highly nutritionally vulnerable. A deficiency of even a single micronutrient—boron for fruit set or calcium for firmness—can compromise the entire cycle. Ultimately, 2026 nutrition must be measured and adjusted in real time. The key is the complete integration of water and nutrient inputs. Only tailored management, supported by constant foliar monitoring, guarantees high yields, oil quality, and orchard longevity.
AIPO Director
Interregional Association
Olive producers
