The best fertilizer for the olive tree foliar fertilization will depend on the time of application of the treatment, mineral deficiencies found…
It must be adjusted to the nutritional requirements of the olive tree and its demand throughout the year.
To increase the contact time of the fertilizer with the leaves of the olive tree, it is important to carry out the foliar applications first thing in the morning or late in the afternoon, so that the mixture remains in contact with the leaves for as long as possible to promote assimilation. In addition, it must be taken into account that the stomata of the leaves close with high temperatures. It must be taken into account that this reduces the assimilation capacity of the foliar fertilizer by the olive trees.
On the other hand, foliar treatments are more assimilable by the new leaves of the olive tree, their application being more effective during spring.
During late summer and early autumn it is interesting to take advantage of the treatment against olive blight or other phytosanitary treatments to add compatible foliar fertilizer.
As we saw in the publication of the fertilizer of the olive tree, it is important to know the deficiencies present in our olive grove. In this way, it is easier to correct deficiencies and increase the productivity of the plantation.
The live tree foliar fertilization can be applied temporarily, taking advantage of other necessary treatments for the olive tree. In specific cases (deficiencies) it may be interesting to do them in a more massive way, especially when the characteristics of the soil or the drought prevent the extraction of nutrients from the soil, making the cover fertilizers useless.
Characteristics of foliar fertilizer for olive trees
Unlike olive tree cover fertilizers, the foliar fertilizerused in the treatments must be 10% soluble in water so that the olive tree can assimilate via the leaves. This requires the removal of impurities and the use of soluble chemical compounds. Because the amount of fertilizer that can be foliar applied is limited compared to soil applications. It is a more effective way when applied to correct micronutrient deficiencies.
Spring and autumn foliar fertilizers
En In spring, the application of nitrogenous fertilizers is common to promote olive growth, although we must take into account that an excess of nitrogen can favor the attack of pests and olive tree diseasessuch as mealybug, repilo or Glyphodes.
It is also good to include important microelements for the olive tree such as Boron.
On the other hand, autumn applications usually include a significant amount of potassium, especially during load years, as this is the nutrient most demanded by olives from the olive tree.
Advantages and disadvantages of foliar fertilizer in olive trees
Main advantages of foliar fertilizer:
- Rapid assimilation of nutrients.
- Reduction of fertilizer losses due to leaching (greater efficiency).
- Prevents the blockage of nutritional elements produced by certain soils.
- Prompt correction of deficiencies detected.
Among the drawbacks of foliar fertilizer, we have:
- Price of foliar fertilizer is much higher than that of top dressing.
- In the same line, the cost of applying the treatments is higher (except if it is added together with phytosanitary treatments that need to be carried out).
- May cause phytotoxicity or burns if the concentration is excessive.
- Some micronutrients such as iron (Fe) are barely assimilated by the olive tree via the leaves.
Price of foliar fertilizer for olive trees
The price of foliar fertilizer for olive trees will depend mainly on its richness in macronutrients and micronutrients. Foliar fertilizers richer in Potassium and with content of essential micronutrients such as Boron are more expensive compared to fertilizers rich in Nitrogen. It also depends on the price of the chemical component used in the mixture, for example, potassium nitrate has a higher price than potassium chloride.
There are different products and brands of foliar fertilizer for olive trees ( Yaravita Olivo, Nitrofoska® foliar, Basfoliar® Olivo, Welgro Olivo Classic, Bayfolan Olivo, Nutriolivo®, Laibono Olivo, Mafa-foliar, Olive Speedfol…)
They are fertilizers specifically designed for the general needs of an olive tree. Many of them, in addition to the macronutrients ( Nitrogen, Phosphorus, Potassium) contain important micronutrients for the olive tree ( Boron, Zinc, Manganese, Molybdenum…) which allows optimal nutrition.
Foliar fertilizers adapted to the needs
At a professional level, foliar fertilizers are adapted to the particular needs of the farm. For this, both soil analysis and foliar analysis of olive leaves are carried out. These data, analyzed by a professional, allow the realization of foliar treatments adjusted to the needs of our olive trees. This allows maximizing the utility of each treatment and can reduce costs since it is cheaper to buy the chemical components separately than mixed.
As a drawback, the calculation of the mixture to be carried out requires advanced technical knowledge to maintain an adequate PH, avoid damaging the olive trees with burns, prevent unwanted chemical reactions, etc…
Chemical compounds used as foliar fertilizer for olive trees
These are some of the chemical compounds used for olive tree foliar fertilization, classified by chemical elements.
- Urea CH4N2O
- Lime nitrate (Avoid mixing with sulfates, phosphates, urea…). Ca(NO₃)₂
- Potassium nitrate KNO3
- Monoammonium phosphate. NH4H2PO4
- Potassium sulfate. K2SO4 (Avoid mixing with phosphates)
- Potassium nitrate. KNO3
- Potassium chloride. KCl
- Monopotassium phosphate. KH₂PO (facilitates collection of olives)
Important: avoid mixing with sulfates, Copper or Calcium.
- Monoammonium phosphate. NH4H2PO4
- Monopotassium phosphate. KH₂PO (Favors the detachment of the olives)
- Borax. Na2[B4O5(OH)4] 8H2O
- Calcium nitrate. Ca(NO₃)₂
- Calcium chloride. CaCl 2
- Manganese sulfate. MnSO4
- Magnesium sulfate heptahydrate. MgSO₄ 7H₂O
- Magnesium nitrate. Mg(NO3)2
- Zinc sulfate. ZnSO4
- Zinc chelated with EDTA or DTPA acid.
Incompatibilities when mixing
Some olive tree foliar fertilizers cannot be used together with other chemical compounds or in certain treatments.
Well because they degrade, this is the case of the reaction between urea and soda lime, which generates ammonia vapors. Or because they precipitate as in the case of phosphates and sulfates when they are mixed with lime. This situation prevents the addition of these fertilizers together with usual treatments such as the Bordeaux mixture.
We have translated the information on our website from Spanish to English. Please note that some words may have had their meaning altered during translation.