Biostimulants for Citrus: Complete Guide for Orange, Lemon, and Mandarin in Spain
The Spanish citrus industry is currently facing the growing challenge of competition from emerging markets such as Morocco and Turkey. In this context, differentiating through quality is the only sustainable strategy for Spanish producers. Biostimulants play a crucial role in improving aspects such as fruit size, sugar content (Brix), shelf life after harvest, and reducing defects in post-harvest. The implementation of effective biostimulation programs can make the difference between a successful citrus campaign and one that is not.
Citrus Physiology and Critical Points of Biostimulation
The physiology of citrus presents unique challenges that can be effectively managed through biostimulants.
Multiple flowering: It is common to observe several episodes of flowering, such as re-flowering or bellflowering. Synchronizing these flowerings is crucial to avoid peaks in nutrient demand and improve fruit set uniformity.
High calcium demand: Calcium is essential for cuticular resistance and prolonging the shelf life of citrus. Its deficiency can result in fruits with poor skin quality.
Sensitivity to water salinity: Especially in regions like Murcia and Alicante, where water quality can be an issue, it is important to manage salinity to prevent osmotic stress in plants.
Harvest alternation: Varieties such as lemon and orange trees often show harvest alternation. An appropriate biostimulation plan can help mitigate this effect, ensuring more regular productions.
Ecoganic Program for Citrus
The Ecoganic program establishes a comprehensive biostimulation approach based on the phenological phases of citrus, adapted for different species and specific objectives.
| Phase | Months | Species | Objective | Product | Dose L/ha | Application |
|---|---|---|---|---|---|---|
| Post-harvest | December-January | All | Tree recovery | NITROTECH 16 + TERRA HUMID | 5+3 | Fertigation |
| Start of budding | January-February | All | Activation of buds, roots | BOOST UNIVERSAL + BALANCE 7-7-7 | 3+5 | Foliar |
| Full flowering | March-April | Orange/Mandarin | Fruit set, calcium, boron | PHACE + CALCIUM 40% + MICRO PLUS | 3+4+2 | Foliar |
| Continuous flowering | All year round | Lemon tree | Permanent fruit set | CALCIUM 40% + BOOST UNIVERSAL | 3+2 | Biweekly foliar |
| Physiological drop | May-June | All | Fruit retention | CALCIUM 40% + K-FLOW 20 | 5+3 | Foliar |
| Fruit fattening | June-September | All | Size, Brix | PHOSMAX 20 + UNIVERSAL POWER | 3+2 | Monthly foliar |
| Maturation/color | September-November | Orange/Mandarin | Color, Brix, acidity | K-FLOW 20 + FULVEX 25L | 4+3 | Foliar |
Results in the Ribera del Xúquer (Valencia) and Campo de Cartagena (Murcia)
The use of biostimulants has shown significant results in the main citrus regions of Spain.
A 16% increase in fruit size has been observed, which represents a price differential in export, especially in large sizes such as 1-3. Additionally, vitamin C content has increased by 12%, providing a significant nutritional advantage in premium markets.
The reduction of physiological fruit drop has also been notable, reaching a decrease of 25%. The increase in post-harvest shelf life, in terms of an additional 3 to 4 days, is critical for export to distant markets such as the UK and Germany. Finally, the incidence of blemishes on the skin has been reduced, improving the presentation of citrus fruits.
Organic Citrus — The Fastest Growing Market
The demand for organic citrus produced in Spain is on the rise, especially in countries like Germany, France, and the Netherlands. The farm gate prices for organic oranges can be between 30% and 50% higher compared to conventional production.
The Ecoganic program is compatible with the most stringent organic certification standards, such as CAAE, Ecocert, and the European regulation EU 2018/848. Additionally, the reduction in the use of phytosanitary products is an added benefit, as biostimulants strengthen the natural defenses of plants.
Species-Specific Particularities
Citrus fruits present specific particularities by species that must be considered for effective biostimulation.
For the orange tree (Navel, Valencia Late), it is crucial to reinforce applications in May and July to mitigate the two common physiological drops. The mandarin (Clementine, Nadorcott) is particularly sensitive to water stress during July, requiring careful irrigation management.
The lemon tree (Verna, Fino) needs an uninterrupted biostimulation program due to its continuous flowering. Finally, the grapefruit has a high demand for magnesium, making it advisable to add MICRO PLUS in all phases.
Frequently Asked Questions
Does CALCIUM 40% help reduce fruit splitting in mandarins?
Yes, calcium strengthens cell walls, reducing the risk of splitting under conditions of water fluctuations.
Can fertigation be used in clay soil with high EC?
It is possible, but it is important to adjust doses and frequencies to avoid salt accumulation in the substrate.
Do biostimulants help against iron chlorosis?
They can improve the overall health of the tree, but for iron chlorosis, it is vital to correct the availability of iron in the soil.
How often should applications be made on continuously producing lemon trees?
We recommend biweekly foliar applications to maintain consistent fruit set.
Are they compatible with Greasy Spot treatments?
Most biostimulants are compatible, but it is always advisable to conduct prior compatibility tests.
