Crop Guide: Olives Cultivation

 

As mentioned in the previous chapter, before loading the soil with nutrients that will serve the plantation for the first years of its life, soil properties need to be adequate for growing olives. After performing a thorough soil test, the grower should ascertain that the soil is not too acidic, nor too basic or sodic. Should the soil test show a need for soil amelioration, the following means need to be taken.

 

Usually only the surface, i.e., top 18 cm (7 inch) layer becomes acidic enough to require liming. The amount of finely ground limestone required varies with soil texture. In order to raise the pH of the said layer by one pH unit from an initial pH of 4.5 or 5.5, the following rates are needed:

 

Alkali soils may be acidified by application of elemental sulfur. Sulfur in the form of sulfate is not an acidifying material. It is advisable to acidify the soil gradually, over several years. Two small applications of acidifying material a year apart are better than a single large application. Soil acidification reactions may take a year or more to complete, so check soil pH annually to monitor the change. Check pH at the same time each year, as soil pH varies seasonally. Monitor soil pH and wait until the desired pH is reached before planting. Add elemental S according to the clay content of soil. Mix the sulfur into the soil.

 

Examples for application rates:

Sodic soils can be corrected by the application of gypsum. Application rate should be determined by a lab analysis. After the gypsum is applied, the displaced sodium must be leached below the root zone by high rates of irrigation. Organic materials such as manure, cover crop, or crop residues may help improve the soil structure for leaching. In order not to again build up a high sodium load, irrigation water should have a high ratio of calcium and magnesium versus sodium.

 

The following program is recommended for situations where the intended plot is not equipped with irrigation and fertigation systems, the soil is not fertile, and no previous crop residues can be recycled. In such situations the following nutrients, fertilizers and rates are recommended:

In the next two years, it is enough to apply nitrogen only, at app. 11 kg / ha (e.g., 32 kg / ha of AN) per year, while all other nutrients will be supplied by the aforementioned side-dressed fertilizers.

 

Example: Plant density: 500 trees / ha

Soil type: Light to medium

Pre-planting base dressing is done the same way as in paragraph 5.2.

Once planted, apply by fertigation a 1:1 ratio of N & K, as shown in the following table. Start applying phosphorus based on leaf analysis from the third year and on.

 

Table 5.1: Fertilization schedule of non-bearing olive trees

 

 

This program is based on Haifa's product Poly-Feed® 17-10-27 + micro nutrients, a fully water-soluble fertilizer that contains all essential plant nutrients. The following table suggests application timing and rates of this product, assuming that planting takes place in spring.

 

Table 5.2: Fertilization program for newly planted olive trees

 

 

Table 5.3: N-P-K application rates and forms

 

 

5.6 Recommendations for a rain-fed, olive-bearing orchard yielding from 6 to 20 ton / ha (25 kg / tree)

This program is based on Haifa's product Poly-Feed 17-10-27 + micro nutrients, a fully water-soluble fertilizer that contains all essential plant nutrients. If manure is added, rates should be reduced according to the analysis of the manure.

 

Table 5.4: A program for a rain-fed, olive-bearing orchard

 

5.7 Recommendations for irrigated but not fertigated, olive-bearing orchard, yielding 3-5 ton / ha

The total amount of nutrients should be split into 4 – 6 side-dressing applications, from early spring till early summer.

 

5.8 Recommendations for nutrigated (fertigated) olive-bearing orchard

The programs are based on the general uptake curves of the different plant organs depicted in Figure 5.1.

 

Figure 5.1: A scheme of the nutritional requirements of leaves (green curve), flowers (yellow curve) and fruits (red curve)

 

Plant density: 500 trees / ha

Soil type: light to medium

Side-dressing equipment is not available

Foliar spraying equipment is not available

 

Table 5.5: Fertigation schedule according to season and physiological stage of olive trees

* Multi-K® – Potassium nitrate (13-0-46)

** Haifa MAP – Mono ammonium phosphate (12-61-0)

Ammonium nitrate (34-0-0)

 

End fertigation 50 days prior to harvest.

Divide nutrigated rate into weekly doses.

Adjust fertilized rate according to leaf analysis data.

 

Same orchard conditions as in Option I.

 

Table 5.6: Fertigation schedule under Mediterranean growing conditions

* Multi-K^® – Potassium nitrate (13-0-46)

** Haifa MAP^® Mono ammonium phosphate (12-61-0)

Ammonium nitrate (34-0-0)

Divide monthly rates into weekly doses.

Adjust fertilized rates according to leaf analysis data.

 

 

Table 5.7: The effect of tree density on yield and plant nutrient removal

 

Side-dressing equipment is available

Foliar spraying equipment is available

 

Table 5.8: An olive orchard nutrition program based on side dressing, nutrigation and foliar feeding

The latest above-mentioned case illustrates the marked role that foliar sprays can play in the mineral nutrition of olive orchards. We will now elaborate on the subject.

 

5.9 Foliar feeding with Haifa products

Foliar feeding is a fast, highly effective method of providing nutrients when used as a supplement to administer fertilizers through the soil. It is an ideal feeding method under certain growth conditions in which absorption of nutrients from the soil is inefficient, due to temporal or continuous conditions limiting nutrient absorption from the soil, such as uncontrolled weeds, a nematodes attack, water-logging, etc. Precision-timed foliar sprays are also a fast-acting and effective method for treating nutrient deficiencies and plant and fruit growth and improving quality.

 

Here are some operational tips for best results from Haifa's foliar products:

 

Haifa offers a special fertilizer line for foliar applications: HaifaBonus™, Poly-Feed™ Foliar, and Poly-Olive™. These high-K foliar formulae contain a specially developed adjuvant for better adhesion to the leaf surface, improved absorption and prolonged action.

 

HaifaBonus is completely and readily soluble in water at all concentrations recommended for foliar applications. HaifaBonuscontains 100% nutrients and is free of potentially harmful elements. It is therefore unlikely to scorch the leaves when sprayed according to recommendations.

 

HaifaBonus is highly compatible with most pesticides used in olives. It is also compatible with other plant nutrients used for correcting common deficiencies such as magnesium, zinc and boron. It is advisable to confirm compatibility of your intended mix by preparing a sample of the spray materials at their recommended concentrations in order to rule out the possibility of a detrimental cross reaction. This mixture should be sprayed onto small area a week prior to the commercial treatment, in order to assess whether an adverse effect occurs.

 

It is recommended to apply 2 - 4 spray applications of HaifaBonus, from early spring to late summer, 3 – 4 kg Haifa Bonus / 100 liters of water (3% – 5% concentration), at a rate of 8 – 10 liters / tree (according to tree size).

 

Usually, no compatibility problems should be expected while tank-mixing HaifaBonus with copper fungicides and with insecticides, but hydrolysis may occur with dimethoate as it may break down, at pH 8 or higher, in one hour or less. Thus, a pH range of 5-6 should be maintained. An acidifying surfactant / adjuvant should be added to prevent alkaline hydrolysis of the pesticides and to assure nutrient uptake. Read surfactant instruction label for best results. Haifa MAP, also used as a plant nutrient, can be added to lower the pH of spray solution.

 

Table 5.9: Recommended foliar applications with HaifaBonus

Adding Magnisal^™ (Mg source) and boron to Haifa Bonus are preferable for the spring treatment while plain Haifa Bonus is recommended for the second spray.

 

Poly-Olive™ is an ideal fertilizer to enhance vegetative development and fruit production in olive trees.

 

Product analysis

It is recommended to apply Poly-Olive™ at the stage of inflorescence development, before flowering, and during the main stage of fruit development (August – September)

 

Recommended program for foliar feeding with Poly-Olive:

Table 5.10: Recommendedfoliar applications with Poly-Olive 15-7-30+2MgO+ME

 

 

 

Figure 5.2: The effects of spraying Poly-Olive^TM 15-7-30+2MgO+ME on fruit-set ratio and on fruit yield in olive trees

 

Haifa MAP, Haifa MKP, Haifa Cal and Haifa Micro are also suitable for foliar application.

 

5.11 Nutrigation™ (fertigation)

Nutrigation^TM (fertigation) is a technique that combines irrigation with fertilization. During the several decades since this technique was developed, it has become well established as a potent method in modern agriculture, resulting in higher yields and improved crop quality.

 

Application of top-quality water-soluble fertilizers through the irrigation system is the optimal method for providing balanced plant nutrition throughout the growth season. A balanced Nutrigation™ regime ensures that essential nutrients are placed precisely at the site of intensive root activity and are available in exactly the right quantity - when plants need them.

 

Haifa offers a wide range of water-soluble fertilizers for Nutrigation™. All products contain only pure plant nutrients and are free of sodium and chloride.

 

5.12 Soil application - controlled-release nutrition

Multicote™ Agri products are composed of polymer-coated nitrogen, phosphorus and potassium, with release longevity of 2-8 months. This line of products releases plant nutrients gradually and steadily according to an olive tree’s needs throughout the growing season. See additional information in Appendix I.

 

 

Nutrients are supplied in accordance with specific olive tree needs which assure optimal tree development.

Single application per season - This results in a drastic reduction of field labor and application costs, as well as considerably less soil compaction.

 

Minimized losses through leaching, volatilization or fixation in the soil

It is recommended that olive plantations use Multicote™ Agri 17-9-16+2MgO, a product based on 35% nitrogen derived from Multicote™, as follows:

 

5.13 Haifa NutriNet™ - online fertilization and Nutrigation™ programs

NutriNet™ is a unique software program that will assist you to work out the recommended fertilizer rates according to the expected yield of olives under your growing conditions: https://www.haifa-nutrinet.com/

 

Soil-applied fertilization schedule and fertigation rates may vary according to cultivar, climatic conditions, growth stages and expected yield. By using the Haifa NutriNet™ online program, you can obtain Haifa’s recommendations most suitable to your growing conditions by selecting the expected yield, growing method and growth stages.

 

The following is an example of recommendations for two expected yield levels (2 and 6 T/ ha) of fresh olive fruit, as determined by NutriNet™:

 

Once you enter the expected yield in the table, the recommended application rateswill be displayed (Table 25)

Table 5.12: Nutrient requirements - olives

In the example below (Table 5.13), the assumption is that the fertilization in the following olive grove is applied partially by top-dressing (Table 5.14), and partially by Nutrigation^™ (fertigation) (Table 5.15). However, any other application methods can be selected and the recommendations may vary accordingly.

 

Table 5.13: Fertilization – olive (kg / ha)

 

Table 5.14: Top / side dressing - olives

 

 

 

Table 5.15: Water soluble and chloride-free fertilizers rates for Nutrigation™

 

Once you enter the expected yield in the table, the recommended application rates will be displayed (Table 5.16).

 

Table 5.16: Nutrient requirements - olives

In the example below (Table 5.17), the assumption is that the fertilization in the following olive grove is applied partially by top-dressing (Table 5.18), and partially by Nutrigation^™ (fertigation) (Table 5.19). However, any other application methods can be selected and the recommendations may vary accordingly.

 

Table 5.17: Fertilization – olive (kg / ha)

 

Table 5.18: Top / side dressing - olive

 

 

Table 5.19: Water soluble and chloride-free fertilizer rates for Nutrigation™

 

 

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