Crop Guide: Citrus Tree Fertilizer Recommendations

Index:

1. Many benefits with Haifa quality fertilizers
2. Summary of recommended applications with Haifa fertilizers
3. Plant nutrients requirements
4. Soil analysis
5. Plant analysis data
6. Nitrogen
7. Phosphorus
8. Potassium
9. Nutrigation™ (fertigation)
10. Nutrigation™ Recommendations for Young trees
11. Nutrigation™ recommendation of bearing trees
12. Nutrigation^™Schedule
13. Proportional Nutrigation™
14. Nutrigation™ practice in Israel
15. Multicote™ Agri Controlled Release Fertilizers
16. Foliar nutrition

3.1 Many benefits with Haifa quality fertilizers

Either soil application, fertigation or foliar treatments, Haifa provides quality products to benefit of any citrus grower.

Soil application:

Multi-K™ in prilled form, can be applied manually or by fertilizer spreader, a source of nitrogen in nitrate (NO3-) form and chlorine free potassium. Prevents salinity injuries and is quickly up-taken by tree roots.

Multicote™ Agri most suitable when labor is not available or affordable, or where leaching of plant nutrients may occur, this control release fertilizer (CRF) is an ideal solution.

Nutrigation™ (fertigation) Multi-K™, Poly-Feed™, Haifa MAP™ and Haifa MKP™ are water soluble fertilizers, containing major macro and minor plant nutrients. Due to the compatibility and the solubility of these fertilizers, can be fertigated in the most effective way and with most beneficial results.

Foliar applications: 

Haifa Bonus™ affects the external and internal fruit quality: increases size and weight, prevents creasing and splitting, improves soluble solids and vitamin C content. In addition, correct quickly and effectively plant nutrient deficiencies.

Tank mix of Haifa Bonus™ with plant growth regulators, improves their functions.

In addition to nutritional functions, Haifa Bonus™ suppresses scale population, like Floridian Wax Scale, an environmental friendly and economical treatment.

Poly-Feed™ available in many N-P-K ratios to deal with an effective way to prevent and to cure plant nutrient deficiencies.

Magnisal™ will cure in a very quick and effective way magnesium (Mg) deficiencies.

The recommendations appearing in this document should be regarded as a general guide only. The exact fertilization program should be determined according to the specific crop needs, soil and water conditions, cultivar, and the grower’s experience. For detailed recommendations, consult a local Haifa representative.

Disclaimer: Any use of the information given here is made at the reader’s sole risk. Haifa Chemicals Ltd. provides no warranty whatsoever for "Error Free" data, nor does it warrants the results that may be obtained from use of the provided data, or as to the accuracy, reliability or content of any information provided here.

In no event will Haifa Chemicals Ltd. or its employees be liable for any damage or punitive damages arising out of the use of or inability to use the data included.

3.2 Summary of recommended applications with Haifa fertilizers*

Table 10: Summary of recommended applications with Haifa fertilizers*

* For detailed recommendations, refer to the relevant paragraph in the following chapters.

* For detailed recommendations, refer to the relevant paragraph in the following chapters.

* For detailed recommendations, refer to the relevant paragraph in the following chapters.

* For detailed recommendations, refer to the relevant paragraph in the following chapters.

* For detailed recommendations, refer to the relevant paragraph in the following chapters.

* For detailed recommendations, refer to the relevant paragraph in the following chapters.

* For detailed recommendations, refer to the relevant paragraph in the following chapters.

* For detailed recommendations, refer to the relevant paragraph in the following chapters.

3.3 Plant nutrients requirements

The tree age and the expected yield are two important parameters in determining the required plant nutrients (Table 11).

Table 11: Required rates of macro and secondary plant nutrients according to growing stages and expected yield

3.4 Soil analysis

This is useful for measuring pH, available P and certain exchangeable cations, notably Ca and Mg.

Table 12: A standard soil test, using Mehlich-1 extractant, interpretation and phosphorus recommendations for commercial citrus orchards, 1-3 years of age

Application of high rate of magnesium (Mg) fertilizers, may suppress the uptake of potassium (K) due to their cationic competition.

Table 13: The standard Mehlich-1 soil test interpretations and magnesium recommendations for commercial citrus orchards.

However, because citrus trees are grown on a wide range of soil types, it would be difficult to establish standards for all soils. They are therefore usually developed for certain soil types in a given region.

It is usually more difficult to assess the N and K status in the soil because both these elements are subject to leaching, especially in humid regions.

3.5 Plant analysis data

Leaf analysis is an essential tool to determine the required plant nutrients (Table 14). According to leaf analysis results, the fertilization rates and the correct ratio of plant nutrients can help to schedule the fertilization program.

Table 14: Leaf analysis standards for mature, bearing citrus trees based on 4 to 6-month-old, spring-cycle leaves from non-fruiting terminals

3.6 Nitrogen

The form of a nitrogen, either ammonium (NH₄⁺), nitrate (NO₃^-) or amide (NH₂), plays an important role when choosing the right fertilizer for Nutrigation of citrus trees.Nitrate-nitrogen is a preferable source of nitrogen as it suppresses the uptake of chloride (Cl^-) and at the same time promotes the uptake of cations, such as potassium (K⁺), magnesium (Mg²⁺) and Calcium (Ca²⁺). In addition, the nitrate form of nitrogen increases the pH of soil solution near the root system, especially important in acidic soils.

The nitrogen in Multi-K^™ (potassium nitrate, KNO₃) is entirely in nitrate form, which makes it a suitable fertilizer for Nutrtigation™.

Table 15: Nitrogen requirements and recommendations for the first three years after planting

* Other water-soluble N fertilizer may be added and Multi-K^™ rate should be reduced accordingly.

Table 16: Nitrogen requirements and recommendations for trees aged 4-7 years, by variety

* Other water-soluble N fertilizer may be added and Multi-K^™ rate should be reduced accordingly.

Table 17: Nitrogen requirements and recommendations for trees eight years and older

* Other water-soluble N fertilizer may be added and Multi-K^™ rate should be reduced accordingly.

3.7 Phosphorus

Table 18: Test interpretations and phosphorus recommendations for commercial citrus orchards, ages 4 and above

3.8 Potassium

Potassium recommendations also depend on the age of citrus trees. During the first 3 years after planting, K₂O should be applied at the same rate as N (g K₂O/tree). For orchard ages of 4 years and above, K₂O should be applied at the same rate as N (in Kg K₂O/ha). 

Table 19: K recommendations for the first three years of orchard-age

Table 20: K requirements and recommendations for trees aged 4-7 years

3.9 Nutrigation™ (fertigation)

Application of 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.

3.9.1 Nutrigation™ Recommendations for Young trees

• Soil type: Light to medium
• 240 irrigation (application) days per year. If more application days, calculated daily rates should be reduced, accordingly 
• Rates are based on N: K₂O ratio 1: 1

Table 22: Nutrigation™ recommendations for young trees

^* In fertile soils and irrigated water with high content of plant nutrients, rates of fertilizers should be reduced, accordingly.

Table 23: Recommended applications of Haifa MAP™ (12-61-0) when soil test is not available

^* Estimated 240 irrigated days.

3.9.2 Nutrigation™ recommendation of bearing trees

• Soil type: light to medium 
• Tree population:  400-600 trees/ha
• Expected yield: 40 t/ha

The recommended average rates of nutrients (Kg/ha):

Nitrogen:The recommended amount is based on the nitrogen consumption of 4-6 Kg N/ ton of fresh fruit. 75% of the entire amount of nitrogen should be applied from early spring to the mid-summer. It is recommended to split this amount of nitrogen and to apply it proportionally in each one of the irrigation cycles.

The rest 25% can be applied in autumn, after color breaking, or as post-harvest fertilization.

Phosphorus:One or two applications at the beginning of spring.

Potassium: It is recommended to divide the entire amount of potassium and to apply it proportionally in each one of the irrigation cycles from early spring to early summer irrigations.

Nutrigation^™Schedule:

Table 24: Nutrigation schedule on bearing trees

Recommendations for Bearing Trees (higher yield)

• Soil type: light to medium
• Plant population: 440 trees / ha
• Expected yield: 60 ton / ha

The recommended average rates of nutrients (Kg/ha):

Table 25: Nutrigation™ schedule of total plant nutrients per seasonal application

^* Split into low rates and applied weekly ; ^** Split into 1-2 applications

In case of magnesium deficiency, it is recommended to spray with 2% Magnisal^™ (Haifa's magnesium nitrate product) when the leaves of the early spring flush have reached 2/3 of their final size. This Nutrigation™ programshould be adjusted according to leaf analysis data.

3.9.3 Proportional Nutrigation™

Proportional Nutrigation™, (constant concentrations of plant nutrients during the entire irrigation session) is a beneficial tool, mainly when growing on sandy soils (Table 26).

Table 26: Proportional Nutrigation

* P in orthophosphate form serves as a buffer.

3.9.4 Nutrigation™ practice in Israel

Non-bearing citrus trees

Table 27:  Recommended rates of N, P and K, on young – non-bearing citrus trees:

When proportional fertigation is used, the concentration of N, the irrigated water in non-bearing orchard should not exceed 200 ppm (200 g N in 1000 L water).

In fruit bearing orchards grow where leaf analysis is not available, it is recommended to apply 200 kg N /ha/yr, 180 Kg K₂O/ha/yr and once in three years 60 Kg P₂O₅/ha.

Applications of potassium may vary according to soil texture; in light texture soils, low rates of phosphorus in each fertigation may be added, similarly to N, while in heavier texture soils higher rates of P may be applied once a week.

Bearing citrus trees

Apply N throughout the irrigation period according to the harvesting time of the fertigated variety. Varieties that are having color breaking difficulties, it is recommended to complete the N fertigation in mid summer. When proportional fertigation is used, the concentration of N, the irrigated water bearing orchard, should not exceed 50 ppm N (50 g N in 1000 L water).

Phosphorus should be applied, as needed, during the entire fertigated period in equal rates. If orchard is not fertigated, phosphorous should be applied in one portion in either spring or fall.

Applications of potassium may vary according to soil texture; in light texture soils, low rates of phosphorus in each fertigation may be added, similarly to N, while in heavier texture soils higher rates of P may be applied; once a month.

Recommendations according to leaf analysis

Table 28: Recommended potassium application rates according to leaf analysis, for oranges, (Shamuti, Washington navels, Valencia), lemons and tangerines

Table 29: Recommended potassium application rates according to leaf analysis, for grapefruits

Potassium: should be applied in the same rates and methods as nitrogen.

Table 30: Recommended phosphorous application rates according to leaf analysis, for oranges, (Shamuti, Washington navels), lemons and tangerines

Table 31: Recommended phosphorous application rates according to leaf analysis, for grapefruits and Valencia oranges

Phosphorous: When drip irrigation is practiced, it is recommended to apply the phosphorous as a full-soluble product, such as Multi-MAP or Multi-MKP, at a constant concentration, during the entire irrigation season.

When leaf analysis is unavailable, it is recommended to apply 200 kg/ha of nitrogen, 180 kg /ha of K₂O and once every three years, 60 kg/ha of P₂O₅.

Nutrigation^™with recycled water: this kind of water may contain substantial quantities of plant nutrients. Therefore, it is recommend analyzing the water in order to determine the available plant nutrient and to use the leaf analysis results as a guidance criterion for the real application of the fertilizers.

3.10 Multicote™ Agri Controlled Release Fertilizers

There are two main situations in which the use of Multicote™ Agri products are recommended:

1. In the planting hole: It is recommended to apply Multicote™ Agri in the planting hole, to ensure balanced and adequate plant nutrients that are essential during the root development stage and the initial growth. This is recommended both in the nursery, when the seedling is transferred to the growth pot, and when the young plant is transplanted to the new plantation.

2. In sandy soils and high precipitation conditions:  As a standard crop nutrition management, in order to minimize leaching problems and yet to feed the citrus trees with all essential plants nutrients, the grower has a choice of several longevities of Multicote™ Agri to suit crop needs according to local growing conditions.

Multicote™ Agri applications:

To select the right Multicote™ Agri formula and to set application rates, some guidelines have to be followed:

• Release longevity should consider soil temperatures. As the release rate increases with temperature, higher temperatures require formula with extended longevity. Note that the declared longevity refers to release at 21^oC
• Under heavy rainfall or intensive irrigation, formula with higher percentage of coated nutrients is required.
• In any case, the percentage of coated nitrogen must exceed the minimum of 25% of the total N in the product.
• The total rates of nutrients should consider
• Theoretical needs based on removal by the crop+expected losses
• Required/expected yield level
• Farmer’s common practice and experience

Under most conditions, Multicote™ Agri  enables reduction of 10-20% in application rates as compared to conventional fertilization.

Please consult Haifa agronomist to customize Multicote™ Agri  fertilization program to suit your needs.

3.11 Foliar nutrition

Foliar feeding is a fast and highly effective method of supplementing and enriching plant nutrients when needed. Foliar application of Haifa water soluble fertilizers provides needed plant nutrients for normal development of crops when absorption of nutrients from the soil is disturbed, precision-timed foliar sprays are also a fast-acting and effective method for treating nutrient deficiencies.

Foliar application of the correct nutrients in relatively low concentrations at critical stages in crop development contributes significantly to higher yields and improved quality.

Determine safe foliar applied rate:

To verify the safe rate under local conditions, it is advisable to spray recommended rate on a few plants. After 3-4 days check the tested plants for scorching symptoms.

Preparation of tank-mix:

Dissolve Haifa water-soluble fertilizes in about half of the tank volume, and add to the spray tank. When applying together with crop-protection agents, addition of wetting agents is not necessary. To ensure compatibility of tank-mix components, a small-scale test should be performed prior to actual application.

Table 32: Haifa water-soluble fertilizers for foliar application

3.11.1 Haifa-Bonus™ increases yields and enlarges fruits

Foliar treatments with Haifa-Bonus™ proved to increase yield of many citrus species and varieties as well as increases fruit size, an important commercial parameter (Tables 33-35).

Table 33: Effect of Haifa-Bonus™ spray on size, yield and N & K levels in leaves of “Marsh” grapefruit

* 3 % spray solution X 3 applications (April, June, and November)

Table 34: Effect of Haifa Bonus™ on Yield and Fruit Size of “Valencia” oranges

* 5 % spray solution.

Table 35: Effect of Haifa Bonus™ sprays on fruit size of “Shamuti” oranges

Foliar treatments with Haifa Bonus™ not only increases yield fruit size, but also reduces fruit splitting, a problem that may cause a sever reduction in marketable fruits (Tab. 11 - 13).

Table 37: Effect of Haifa Bonus™ on “Nova” mandarins - R. Lavon (1992)

Figure 48: The Effect of Haifa Bonus™ on Yield & Fruit Size of Ruby-Red Grapefruit

Haifa-Bonus™ also reduces the fruit drop and affects the fruit quality (Tables 38-39).

Table 39: Effect of Haifa-Bonus™ spray on “Lisbon” Lemons (USA)

* 3 % spray solution X 3 applications (April, June, and November)

3.11.2 Foliar feeding on young trees

Table 40: Foliar feeding with Poly-Feed^™ on young citrus trees to stimulate growth

* add surfactant

Table 41: Foliar feeding to correct deficiencies

3.11.3 Foliar feeding prevents creasing and splitting, and improves fruit quality

For many years, foliar applications of Haifa-Bonus npK fertilizer proved to be an efficient treatment to reduce creasing in oranges (Tab. Xx).

Table 42: Foliar application of Haifa Bonus™ increases leaf K and reduces creasing in “Valencia” oranges

* 5 % spray solution.


Based on research results, the recommended treatment to reduce creasing is, to apply 4%-6% Haifa Bonus™ npK: 1st application on Mid June (after June drop), and 2nd application one month later (Table 43).

Table 43: Recommended foliar treatments with Haifa-Bonus™ npK

Table 44: Growth regulators treatments, affecting fruit size and tree productivity, by variety

Need more information about growing citrus? You can always return to the citrus tree fertilizer & citrus crop guide table of contents