Crop Guide: Banana Fertilizer Recommendations

Index:

1. Nutrient uptake/removal
2. Soil test
3. Leaf analysis
4. Interpretation of nutrient status (lamina 3)
5. Nutrients demand
6. Summary: Nutrient uptake - N, P, K
7. Nitrogen
8. Suggested fertilizer rates and their plant nutrients content
9. Haifa NutriNet™ web software for Nutrigation™ programs
10. Soil-applied fertilizers
11. Examples of soil-applied fertilization practices
12. Controlled release fertilizers
13. Nutrigation ™ (fertigation)
14. Foliar feeding

Banana plants need fertile soil and an abundance of soil moisture for best growth and production. The development rate the plant makes in its first 3-4 months determines the weight of the bunch and the number of hands. Consequently, it is essential to provide the best care during this period.

Placement - Soluble potassium, phosphorus and nitrogen fertilizers can be made easily available to the roots after planting. Application can be done in various forms; 1) Soil application broadcast or localized. Since banana roots quickly ramify away from the pseudostem, fertilizers should be rather broadcast than concentrated around the pseudostem.

2. Nutrigation (Fertigation- fertilizer placement via irrigation) is most efficient since nutrients are applied directly to the root zone

Timing - Fertilizing schedule should coincide with climatic conditions and phenological stages of the crop.

Frequency - Frequent applications are especially important where the soil is light and lacking in fertility and when rainfall is heavy. Because of its limited mobility in the soil, P fertilizers should be applied once or twice annually in the subtropics. N, K fertilizers are normally applied at short intervals via the irrigation system. In humid tropics, intensive leaching due to extremely heavy showers dictates immediate fertilization via soil application in order to compensate for leaching losses.

Application frequency can be reduced significantly when Multicote_^™, controlled-release fertilizer, is used.

By using Multicote_^™, less leaching of plant nutrients, if any, will occur and less applications are required.

4.1 Nutrient uptake/removal

Uptake of macronutrients is in the following mass order: Potassium (K) > Nitrogen (N) > Calcium (Ca) > Magnesium (Mg) > Phosphorus (P), see table 21.

Uptake of micronutrients is in the following mass order: Manganese (Mn) > Iron (Fe) > Boron (B) > Zinc (Zn) > Copper (Cu).

N, P, K, Mg, and Cu have a high re-translocation rate compared to other nutrients.

Table 21: Nutrient removal by banana plants (cv.Cavendish)*

* 50 ton/ ha of fresh fruit @ 2000 plants / ha

N:K ratio*

Critical leaf N:K ratio for optimum yields varies between 1:1 and 1:1.6, depending on method for leaf analysis.

Low N:K ratio results in:

• “Finger Drop” (Dégrain) – a post-harvest problem of ripe banana bunches, called. Finger Drop occurs during hot, wet seasons in tropics, if K supply is low, so that NH₄⁺ accumulates.
• Delay in bunch emergence
• Widely spread hands, easily damaged during transport
• Fruit pedicles are fragile and when ripe, fruit fall from the bunch
• reduced wind resistance

*  Banana Nutrition (Lahav & Turner), IPI-Bulletin No 7 (1985), Irizarry et al. (1988), Garcia et al. (1980), Oschatz (1962)

On soils high in Sodium also Na⁺ has to be considered for the optimum cationic balance

e.g. problems with high Na:(K+Mg+Ca) ratio as in Canary Islands (Banana Nutrition : Lahav & Turner) IPI-Bulletin No 7 (1985); Banano (ed.: Rosero Ruano); Godefroy-Lachenoud, 1978).

Here again, Multi-K™, either water soluble or Multicote, a coated CRF potassium nitrate, can not only be ideal source of K⁺, but also due to the antagonistic cation (K⁺) effect, can reduce or prevent the uptake of sodium.

4.2 Soil and leaf analysis
 

4.2.1 Soil test

Soil tests should be practiced to establish an effective, economical fertilizer program. The soil test for N is often considered an unreliable indicator of soil N status under banana, as close relationships between soil N test and banana response to applied N are difficult to obtain.

Bananas perform best in soils with a pH of 5.0 (calcium chloride) or above. The table below provides a guide to preferred levels for bananas from a typical soil test.

Table 22: Guide to preferred levels for bananas from a typical soil test

As a result, soil test information is usually combined with local knowledge as variation occurs between areas (Tab. 24) to construct an optimal fertilization program.

Table 23: Soil analysis – critical values

(Godefroy and Dormoy (1988); Turner et al. (1989); Rosero Ronano (2000)

* millequivalent/ 100 g soil

4.2.2 Leaf analysis

For many years, leaf samples were taken from the 7^th petiole and from the 3^rd lamina. During these years hardly any changes took place in the laminae nutrient standards, while over the years, increased levels of N, P and K in the petioles, were adopted (Fig. 44).

Figure 44: Changes of N, P and K content in the 7^th petiole over the years

Also, the vegetative mass of banana plants was increased, mainly due to better varieties, intensified fertilization schedules and rates. Consequently, nutrient content in plants increased as well (Tab. 24).

Table 24: Banana plants mass increased from the 1960s to the1990s

(Lahav and Lowengart, 1998)

The third leaf from the top of the pseudostem of recently flowering (shot) plants is usually sampled for analysis.

Table 25: Recommended critical nutrient levels using the third leaf as sample leaf

Samples are taken from the leaf parts at different positions on the plant (Fig 45.

When to sample: The samples should be taken either just before flowering or following floral emergence and when all female hands are visible.

Which tissue to sample:  In most banana-producing countries the laminar structure of leaf 3 is sampled for tissue analysis (IRS method, 1975). However, samples of the central vein of leaf 3 and the petiole of leaf 7 are also used. The laminar structure of leaf 3 is sampled by removing a strip of tissue 10 cm wide, on both sides of the central vein, and discarding everything but the tissue that extends from the central vein to the center of the lamina.

Figure 45: Sampling parts of banana leaves

4.2.3 Interpretation of nutrient status (lamina 3)

Table 26: Standards of N, P and K levels in banana lamina

Table 27: Contents of Macro-nutrients in banana leaves (% in Dry Matter)

Table 28: Contents of Micro-nutrients in Banana Leaves (ppm in Dry Matter)

Table 29: Interpretation of macro and secondary plant nutrient status (lamina 3)*

* - IFA manual – average of literature review

Table 30: Interpretation of micro plant nutrient status (Martin-Prevel (1999 - IFA-manual)

*May also consider P/Zn ratio (high = Zn deficiency)

Table 31: Interpretation of micro plant nutrient status - Growth stage: Large / fully grown sucker

(Martin-Prevel (1999 - IFA-manual)

4.3 Nutrients demand

Nutrient management according to nutrient uptake and removal – general recommendation*:

• The nutrient uptake of the whole mats is a base for fertilizer application, only when fertilizing the first crop
• For ratoon crops, crop residues of the previous crops, like leaf trash and cut pseudostems supply additional nutrients – less fertilizer is needed
• Nutrient losses from fertilizers and trash have to be considered for calculating fertilizer rates for plant and ratoon crops
• Split application of fertilizers reduce nutrient losses
• In particular, N and K losses can be high

* Irizarry et al. (1988); Twyford & Walmsley (1973/74/76); van der Vorm and van Diest (1982)

Removal of plant nutrients in the harvested banana fruit is one of the major considerations in formulating fertilizer recommendations. The quantities of plant nutrients contained in the whole plant and in the fresh fruit harvested and removed from the field, are the basis for scheduling the fertilization program. The large amounts of K reflect the high K content in the fruit. When the previous crop is being left in the field, the contribution of recycled plant nutrients should be taken into consideration (Tab. 32).

Table 32: Plant nutrient requirements vary according to expected yield and plant growth, considering the contribution of recycled plant parts from the previous crop (expected yield: 30-60 ton/ha)

Table 33: Nutrient Uptake by Cavendish Banana (per Mt of whole bunch banana)*

* - IFA World Fertilizer Manual, 1991

Summary: Nutrient uptake - N, P, K

• Nitrogen
  constant need for N throughout the growth period
• Phosphorous
  constant need for small P amounts throughout the growth period
• Potassium
  constant need for K throughout the growth period
  80% of K application should be done before peak flowering
  Smaller K rates at early stages, increased K rates in month before and after flowering (from “large” to “shot”)
• Magnesium
  constant need for small Mg amounts throughout the growth period.
• Calcium
  Main Ca uptake until shooting/shot
  No net Ca uptake into bunch after shooting
  Main Ca application for fruit production should focus on periods before shooting
• Sulfur
  The most rapid S uptake occurs from sucker to shooting stage.
  After shooting the uptake rate is reduced.

4.3.1 Nitrogen

The form of nitrogen (N) either ammonium (NH₄⁺) or nitrate (NO₃^-), plays an important role when choosing the right fertilizer for Nutrigation of banana plants.

Nitrate-nitrogen (NO₃^-) 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 (Mg⁺) and Calcium (Ca⁺⁺). Also, the nitrate form of nitrogen, increases the pH of soil solution near the root system, which is an especially important feature in tropical acidic soils.

The nitrogen in Multi-K™ potassium nitrate is entirely in nitrate (NO₃^-) form, which makes it a suitable fertilizer for fertigation.

A better solution is to use Multicote™, Multicote_^™ AGRI and CoteN™, controlled-release fertilizers, which would release gradually all plant nutrients according to plant’s needs, while preventing leaching losses.

4.4 Suggested fertilizer rates and their plant nutrients content

Common standards for applying N, P and K*

• N
  Split N application
  Every 1-3 month in relatively dry climates
  In humid tropics, at high rainfall, or irrigation; apply every 2-4 weeks, while with MulticoTech™ (4M), apply every 10 weeks.
• P 
  P application once/year broadcast to ratoon crops or incorporated into soil before planting
  On P fixing soils; rates may be 4 times higher than plant need
  In healthy plantation P dressings may biennially
• K 
  80% of K should be applied by flowering
  Apply K more frequently under leaching conditions
  Rates of K according to soil analysis, e.g. if exchangeable K is < 0.4 meq/100 g soil

* - Lahav & Turner (1989 - IPI-Bulletin No 7), Martin-Prevel (1999 – IFA manual)

4.4.1 Haifa NutriNet™ web software for Nutrigation™ programs

Haifa fertilization recommendations are available online and can be accessed through the following link: https://www.haifa-nutrinet.com 
NutriNet™ is a unique software program that will assist you to workout the recommended fertilizer rates according to the expected yield under your growing conditions.

Soil-applied fertilization schedule and fertigation rates may vary according to cultivar, climatic conditions, growth stages and expected yield. By using Haifa NutriNet™ program on-line, you may 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 (30 and 60 T/ha) of banana, as determined by NutriNet™:

* Fertilizers produced by Haifa. For details, see Appendix X.

Table 35: Amount of fertilizers (kg/ha/year) and their applied plant nutrients, for expected yield of 60 MT/ha, respectively

* Fertilizers produced by Haifa. For details, see Appendix I.

4.4.2 Soil-applied fertilizers

In soils with low fertility, such as sandy and calcareous soils, bananas should be fertilized frequently (minimum 6 to 8 times a year) for maximum production. 35% of N, P, and K application should be applied during vegetative growth after planting and before flower differentiation, 40% before flower emergence, and the remaining 25% after flower emergence. The potash requirement is high and Multi-K™ with a high K₂O content (13-0-46) is recommended as a source of K. The N-P₂O₅ -K₂O ratio of 3-1-6 is recommended. A suggestion to prepare such ratio of water-soluble fertilizers, is presented in Tab. 36

Table 36: Preparation of 1 ton 3:1:6 ratio N:P2O5:K2O water soluble fertilizer

The dry form of Multi-K™  is also suitable for broadcasting in the banana plantation, either manually or with fertilizer spreaders. Two forms of Multi-K™  enable perfect matching with the grower’s means, i.e. soluble, made of crystalline particles, and prills (2-3 mm granules). Both forms are fully water soluble, however, the prills form may be most suitable for hand and mechanized spreading. The prills is the form of choice also for blending withother granulated fertilizers.

Figure. 46: A common technique of side dressing in a concentrated band near the plant (Central - and South-America)

The amount of fertilizer depends on size and age of the stalk and on the number of stalks per mat (Tab. 37). Fertilization of young plants should be started with N-P₂O₅-K₂O ratio of 3-1-6 (when higher analysis formula is used, amount of fertilizer per mat should be reduced, proportionally), with 2-3% magnesium, applied every 2 months, and increasing gradually to 2.5 kg to 3.0 kg at flowering and fruiting time, 10 to 18 months later.

Table 37: Fertilizer program for banana plants 1

¹- A fertilizer containing nitrogen, phosphate, potash, should be applied every 2 months

     throughout the year.

²– In case of a fertilizer with higher analysis, the amount should be reduced proportionally.

³- Foliar applications of micronutrients may be applied 1-2 times per year.

⁴- Iron applications, especially in calcareous soils, should be made 1-2 times per year.

If manganese (Mn) and zinc (Zn) are needed, at least one nutritional spray containing manganese and zinc is recommended annually. Copper should be included in the spray if no copper-containing fungicide is used. Banana plants growing in acidic sandy soils may be fertilized with 0.25 to 0.5 kg dry iron sulfate 1-2 times during the warmer part of the year. Banana plants growing in high pH, calcareous soils may be fertilized with 30 to 60 g of chelated iron material (EDDHA) during the warmer part of the year.

4.4.3 Examples of soil-applied fertilization practices

The following is considered a common practice in several banana growing countries:Please note that application values may differ among locations, yields, application methods, etc., but generally the application rate of potassium is 1.5-2 fold higher than that of nitrogen.

a. Colombia,  Santa Marta , a common practice is:

Table 38: Common fertilization practice in Colombia

b. Tropical regions

Plant density: 1200-1800 mat/ha Expected yield: 45-80 T/ha

Table 39: Fertilization practice in tropical regions

* In regions with neither water salinity - nor soil salinity problems, SOP can be replaced by 

KCl during the wet season only. ** 30% of the annual potassium requirement should be applied at the time of bunch initiation.

The annual quantity of the recommended fertilizers should be divided to as many and as frequent applications as possible. In plantations without irrigation facilities, the applications should be done during the rainy season only.

c. Soil salinity area:

In an area that suffers from soil salinity, with plant density: 1200-1800 mat/ha and expected yield: 45-60 MT/ha, the fertilization practice is:

Table 40: Fertilization recommendation in saline areas

(Source: Suescun and Eduardo 1993.)

* The annual amount of the recommended fertilizers is divided to 6-8 applications. In growing areas without irrigation facilities, the applications are done during the rainy season.

AN = Ammonium nitrate, 33,5-0-0 Haifa MAP = Mono ammonium phosphate, 12-61-0

Multi-K^™ = Potassium nitrate 13-0-46

d.  West Bengal

Table 41: Fertilizer recommendations for banana (Giant Governor)

* Applied in split applications throughout the growing cycle. Fertilization is done on the 3^rd, 6^th and 9^th months after planting.

e. Subtropical regions

Table 42: Fertilizer recommendations

* in regions with neither water salinity - nor soil salinity problems, SOP can be replaced by KCl during the wet season only. 
** 30% of the annual potassium requirement should be applied at the time of bunch initiation.

Table 43: Nutrient recommendations in banana growing areas*

* - Martin-Prevel (1999 – IFA manual)

4.5 Controlled release fertilizers

Haifa'’s Multicote^™ Agri products contain polymer-coated fertilizer granules, that slowly release plant nutrients into the soil solution at a pre-determined rate. Moisture in the soil is absorbed by the encapsulated fertilizer granules - dissolving the nutrients inside and releasing them into the root zone.

Why to use Multicote Agri?

• Multicote™ Agri can be used in any kind of soil. The release rate is determined exclusively by the soil temperature, which is also a major factor affecting plant growth rate.  Soil type, humidity, pH, and microbial activity do not affect the release rate
• In tropical regions, where heavy rains may leach out plant nutrients from the root zone and where many fertilizer applications are required to offset loses, Multicote^™ Agri  will be the ultimate solution. It is not affected by soil moisture or heavy rainfall, as it releases gradually plant nutrients.
• Since banana crop requires heavy and continuous feeding, many fertilizer applications are required. Consequently, Multicote^™ Agri saves on number of applications, thereby it considerably saves labor.
• Many experiments and field trialsproved the efficiency of this product, resulting in higher yields.
• The efficiency of Multicote^™ Agri , due to a continuous nutrients release into the soil solution is much higher than conservative fertilizers. Consequently, lower rate of Multicote^™ Agri may be applied; saving on fertilizer expenditure as well as on freight cost.
• Wherever environmental concern over fertilizer ground-water contamination is an issue, Multicote^™ Agri will be the product of choice.

Multicote™ Agri application concepts:

In many banana-growing countries Multicote_^™ Agri proved to produce the highest yield at a competitive cost as compared to regular fertilization. There are two main application concepts:

1. In tropical regions with heavy rains, the use of Multicote_^™ Agri will result in considerably less losses of plant nutrients as compared to conventional fertilizer applications. Also, less applications per year will be required.
2. In irrigated banana plantations where fertigation is practiced, Multicote_^™ Agri can be applied during the rainy season where irrigation is not being practiced. This combination of both application methods, will save labor and ensure continuous plant nutrients supply during the rainy period.

4.5.1 Application recommendations

In tropical regions and where heavy rains may leach plant nutrients from the root zone of banana plant, Multicote_^™ Agri  is recommended. Based on field trials and growers experience, Multicote_^™ Agri 17-7-25+2MgO can be applied every 2 months at a rate of 260 g/mat /year.

In irrigated fields, where only part of the growing period (about 4 months) is a rainy season, two applications of Multicote_^™Agri at a rate of 145 g / application /mat are recommended.

The rest of the time, about 8 months, water-soluble fertilizers should be fertigated. A water-soluble N-P-K fertilizer of a 3:1:4 ratio may be applied, such as 14-5-18 or 17-6-22. Eight monthly applications, of 150 g / application / banana plant, are recommended.

4.5.2 Multicote Agri proven performances

In Colombia, in cooperation with Chiquita, Multicote™ Agri was compared to the regular commercial treatments (control). The N-P-K quantity was the same in all treatments while four combinations of  Multicote™ Agri content in each treatment varied from 100%, to 75%, 50% and 25%. The growth of the plant was measured: circumference, height of mother and daughter plants, % bunches emerging per week and number of weeks per plant.

Multicote Agri™ performed better than the control on the 50-100% nutrient applications was practiced. (Figs. 47 a-d)

Figure 47 a-d: The effect of  Multicote^™ Agri on growth of banana (cv. Williams)

In the Philippines, a large-scale experiment was carried out by Mt. Kitanglad Agriventure, Inc. (MKAVI) in Lantapan, Bukidnon, comparing  Multicote™ Agri 12-0-44 to the regular fertilization program (control) (Tab. 45). The objective was to determine the effect of improving common intensive nutrition scheme by applying the N & K as Multicote™ Agri treatments:

Treatments:

Control

Multicote™ Agri 12-0-44, 800 kg/ha

Multicote™ Agri treatment produced higher and earlier yields, compared to the control plot. 

Figure 48:  Multicote™ Agri treatment resulted in earlier emergence of bunches in Banana (cv. Williams)

Conclusion:

Multicote™ Agri increases the profits of banana growers by reducing number of applications and fertilization rates, and by producing higher yields.

4.6 Nutrigation ™ (fertigation)

As explained in the beginning of this brochure, the banana is a tropical herbaceous evergreen plant with no natural dormant phase. Therefore, it has a high water demand throughout the year, especially at high temperatures. In this respect, the important properties of the banana plant are:

• High transpiration potential due to the large broad leaves and high leaf area index
• Shallow root system as compared with most fruit tree crops
• Poor ability to withdraw water from soil beneath field capacity
• Rapid physiological response to soil water deficiency

These properties make banana plants extremely sensitive to slight variations in soil water content, and emphasize the importance of correct irrigation scheduling.

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

The main advantage of all micro-irrigation systems is that they are spread across the field and a large area can be irrigated from a single control point. Labor requirement is therefore minimal, uniformity of application is high, a specific root zone area can be continuously wetted and any desired irrigation regime can be applied. In addition, water loss by evaporation is minimal especially when drip irrigation is practiced. Soluble fertilizers can be applied easily and efficiently through the system directly to the root zone.

• When fertigation is carried out via drip system or micro-sprinklers, it allows expanding the growing areas to marginal lands with a limited water-holding capacity. Such instances may be sandy or rocky soils, where accurate control of water and nutrients in the immediate vicinity of the root system is critical.
• In Hawaii, shifting to drip irrigation combined with nutrigation in bananas has doubled the yield obtained from a well-managed, conventional sprinkler-irrigated plantation.

Table 44 provides an illustration for the responsiveness of the banana to Nutrigation™ with Multi-K^™ potassium nitrate.

Table 44: Effect of different potassium sources on bunch weight and total yield of bananas supplied with 600 kg/ha/Yr of K20 in the form of either K2S04 or Multi-K™ or a combination of both (1:1)*

* - Guerrero and Gadban, 1996  “Laoespensa” Cienaga Magdalena. Colombia

* Benefit/cost ratio expresses the ratio between the additional benefit/income and the additional cost associated with the treatment.

The results of this trial show that Multi-K™ is markedly superior to K₂S0₄, agronomically and economically.

Tropical regions

Plant density: 1200-1800 mat/ha;

Expected yield: 45-60 MT/ha

Table 45: Nutrigation program in tropical regions

* In regions with neither water salinity - nor soil salinity problems, SOP can be replaced by KCI during the wet season only. 
** 30% of the annual potassium requirement should be applied at the time of bunch initiation.

• The annual quantity of the recommended fertilizers should be divided to weekly applications.
• During the rainy season fertilizers should be applied by means of short (technical) irrigation cycles, designed for this purpose only.

Subtropical regions

Table 46: Nutrigation program in subtropical regions

* In regions with neither water salinity - nor soil salinity problems, SOP can be replaced by KCI during the wet season only. 
** 30% of the annual potassium requirement should be applied at the time of bunch initiation.

• The annual quantity of the recommended fertilizers should be divided to weekly applications. The common practice is to divide the entire amount of fertilizers by the number of the irrigation weeks. The fertilizers are supplied in weekly amounts.
• Alternatively, the fertilizers can be applied continuously with the irrigation water, at a constant rate - proportional fertigation.

Table 47:

* 30%of the annual potassium requirement is applied at time of bunch initiation. 
** All the nitrogen amount is supplied during autumn by Multi-K™ and Haifa MAP™

4.7 Foliar feeding

The plant roots readily absorb most mineral nutrients. However, many other plant organs are able to absorb nutrients in their ionic form from solutions. The extensive area of plant leaves makes them a natural candidate as a complementary feeding channel. Indeed, this method is now widespread in feeding management of many crops. The unique advantages that this method offers for banana growers are as follows:

• When the banana crop require plant nutrients, which are fixed and immobile in the soil.
• When deficiencies are detected at advanced stages of plant growth, and a quick correction is necessary.
• When root activity is hampered by external stresses such as low soil temperature, poor aeration, nematodes, rodents, or damage by machinery.
• When the effectiveness of direct soil application is limited due to weed infestation. As foliar application bypasses weed competition, this method ensures high availability to the target organs.
• When the roots are unable to provide the plant with certain nutrients at adequate rates, during specific critical stages of growth. This syndrome may take place even in fertile soils.

4.7.1 Foliar feeding practices

In Martinique, Philippines, Colombia and elsewhere it has become a prevailing practice to apply Haifa Bonus npK at a rate of 70 -100 g/mat (25-30% of the yearly potassium requirement) at the time of bunch initiation. The high availability of Haifa Bonus npK to the plant makes it the best fertilizer in meeting the plant’s increasing demand for nutrients at this critical stage of plant development that determines yield.

In Colombia, Mexico and elsewhere, foliar sprays during the vegetative growth and bunch development were found to be remarkably beneficial in increasing bunch weight, number of hands per bunch and number of fingers per hand (Tabs. 50, 51).

Table 48: Effect of foliar application of Haifa-Bonus npK on banana plants at two locations, in Colombia*

* Guerrero and Gadban, 1992,  “La Ceiba” Santa Maria, Colombia** Six spray applications at 2% concentration, at 30-days intervals.

* Guerrero and Gadban, 1993,  San Rafael Cienaga Magdalena, Colombia 
* Four spray applications at 30-days intervals at 2% concentration. 
*** Ratio between additional benefits and the additional cost associated with the treatment.

It is a Costa-Rican banana growers’ practice to make 44 foliar-spray applications per year to control Black Sigatoka disease. Researchers from CORBANA (Corporacion Bananera Nacional) have found positive effects on vegetative growth and bunch development, when 22 of these applications were combined with Haifa Bonus npK at600 g/ha (Tab. 52).

Table 50: Advantageous effects of combining Haifa-Bonus npK in pesticide spraying*

 Sancho and Guzman, 1996)

It is a Mexican banana growers’ practice to make 36-44 foliar spray applications per year to control Black Sigatoka disease. They use to combine Haifa-Bonus npK with the pesticides Bravo 720 and Tilt as follows:

Ground spraying: 2-4% Haifa-Bonus npK in 300-400 liter/ha spray solution.

Air spray application:7-8% Haifa-Bonus npKin 20 liter/ha spray solution.

4.7.2 Foliar application recommendations

When application is done by ground spraying, the rate should be 2-4% Haifa-Bonus npKdissolved in 300- 400 liter/ha spray solution. Total rate: 6-12 kg/ha. When application is done by aerial spraying, the rate should be 8-10% Haifa-Bonus npK dissolved in 20 liter/ha spray solution.

Time and number of applications:

In subtropical regions:

Three to five spraying treatments at 3-4 week intervals. Recommended concentration for ground application is 2-4% Recommended concentration for aerial application is 8-10%

In tropical regions:

Applications can be done throughout the year, up to 22 applications, that can be tank-mixed with pesticide sprays.

Compatibility:

Haifa-Bonus npK is highly compatible with most pesticides used in banana cultivation. 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 prior to commercial treatment, in order to assess whether an adverse effect occurs.

Susceptibility:

High temperature and low humidity may increase the susceptibility of banana plants to possible spray injury. The preferred time for spraying is early morning or late evening. Plants under stress conditions should not be sprayed!

Need more information about growing bananas? You can always return to the banana crop guide table of contents & banana fertilizers

Related Articles:

NPK Fertilizers - Water Soluble Fertilizers

Informations about Plant Nutrition

Read more about Foliar Feeding

Informations about Potassium Nitrate Fertilizers