Crops from the Vaccinium genera belong to the Ericaceas family. Their species are widely distributed in Europe and USA. Vaccinium genera are classified in two groups: Male Blueberries (Blueberries, heildelbeere) and Female Blueberries (Cranberries, Poiselbeere, Airelles).

There are mainly two types: Highbush blueberry and rabbiteyes blueberry.

The first is characterized for being self fertile variety, and then plantings can be established as only one cultivar (variety), even though it has been verified, when two or three varieties are placed in the orchard, larger size and early maturity fruits are obtained.

The highbush blueberry is the specie that first was planted as a crop and is the one that produces better quality in terms of size and flavor. Even though, Rabbiteyes blueberry is considered of less economical importance, it has the advantage of requiring a short winter, is not as demanding on soils and is more resistant to alkaline pH, heat and drought.

Soil: characteristics are determinant for a good Berries´ development, since their physical characteristic define roots development and crop’s water holding capacity. Also, in relation to their chemical characteristics determine essential nutrients´ availability for growing and production; besides in some cases, there are toxicity problems for the crop by the presence of some element.

Soil pH is a characteristic that define nutrients´ availability for the crop. Blueberries grow better on the following soil characteristics: humid, acid (pH 5-5.5), sandy, sandy or clay peat not very deep, and low fertility. In general, due to their humid and oxygen demands, the soil must have good drainage, high water holding capacity and porosity for proper aeration. When soils´ acidity conditions are not adequate for the blueberry crop (higher pH), it is necessary to perform management practices that allow to increase acidity (diminish soil pH). Among them, one of the most efficient and economic convenient is the application of sulfur (elemental sulfur). Even though, it must consider that a soil pH alteration affects the nutrients´ availability for the crop.

Main Nutrients
The application of balanced nutrition aims to ensure adequate aerial and root growth to store as much carbohydrate in specialized organs. Adequate nutrition of the crop is a key factor in obtaining good harvests.

To achieve an appropriate nutrition plan in blueberry is necessary to know the nutrient demand in quantity and type of nutrient. It is also important to know the role of each nutrient for crop growth, yield and quality of production.

For obtaining an adequate nutritional plan on berries, it is necessary to know the nutrients’ demand according the quantity and nutrient type. Also, it is important to know the role of each nutrient on the crop’s growing, yield and production quality.

Nutritional demands of different berries species significant differ between them, due to their different growing behavior and production levels. Similarly, the optimum foliar levels also differ for each of these species.

The demand or nutrients´ extraction for the crops has been determined by numerous authors, which have generated these values principally for macro-nutrients. A Summary of the described information, in the existing literature about this topic, is presented in the following tables:


Estraction (kg/ton Fruit)

Critical foliar level (%)


















Comparison of nutrients´ extraction levels by ton of fruit and foliar levels for Blueberry. - Source: Vidal y otros 1999 y Vidal y Burgos 2003.

Annual growing can vary according to the climatic and soil conditions and technological or management level of the orchard. In each of these conditions a different requirement level is determined for satisfying the photosynthates´ formation, cellular structures and metabolic reactions. The demand of annual growing components considered is: fruits, leaves, sprouts, roots and an increment of permanent structures.

For calculating nutritional doses it must be considered the nutrients´ content of the exported tissues from the orchard, which are the pruning and fruit residues (not incorporated), since leaves and roots remain finally in the soil and are recycled.

As the plant is increasing the production also increases its requirement of potassium due to the high extraction that fruit produced, being this nutrient essential for a good production level and desire quality.

Besides, to determine the nutrients concentration of tissues it is important to know the development of these tissues during the crop growing cycle, with the objective to define the periods and adequate nutrients´ quantities to apply.


Yield level (ton/ha)

N Requerimient (kg/ha)

P2O5 Requirement (kg/ha)

K2O Requirement (kg/ha)














Blueberry´s annual requirement of nitrogen, phosphorous and potassium in the productive stage for three yield levels. - Source: Hirzel y Rodríguez 1993.
Nutrients Role
The mayor quantities of extracted nutrients for berries are potassium, nitrogen and calcium which are important for determining yield and quality for the plants.

The Berries´quality parameters demanded by fresh and frozen markets are based principally on appearance (color, size, shape and lack of defects), firmness, flavor (soluble solids, acidity and volatile aromatic compounds) and nutritive value (Vitamins A & C).


Way of Absorption

NO3- y NH4+

Function in the plant

Proteins´ component, chlorophyll and enzymes
Enhance vegetative growth.


General yellowish color for detection of chlorophyll production.


Excessive vegetative growth
Soft and succulent tissues
Soft fruit

The required nitrogen levels for this type of crops are not high; it is important in the development vegetative phase and at post harvest. An excess of this nutrient causes serious fruit quality problems, producing soft fruit and very susceptible to mechanical damage and diseases.


Way of Absorption


Function in the plant

Regulates osmotic and sugars transport to the fruit
Activates more than 60 enzymatic processes.


Light green color leaves, with marginal necrosis and wilting
Size loss and fruit consistence
ow level of soluble solids (brix).

This nutrient is of mayor importance for fruit yield and quality on berries, since it is in charge of carbohydrates mobilization from the leaves to the fruit. The main effects of potassium are: improving fruit quality and color, and increasing sugar content. This is especially important for the frozen market.


Way of Absorption


Function in the plant

Firmness and cell structures, cementation of cellular walls
Structure and permeability of cellular membranes.


Death of growing apices in roots and leaves
Weak stems
Problems of tissues firmness specially fruits due to calcium deficiencies.

The effect of this nutrient on Berries is very important for fruit quality, since this fruit is very perishable. A good supply of calcium is essential to increase fruit durability at post harvest, especially during transport and fresh market.

It is important to consider that calcium absorption by the plant is produced early until the fruit set and photosynthetically active. From this period the calcium absorption becomes lower and generally does not reach the fruit. Then, it is necessary to use calcium foliar application to the crop.


Way of Absorption

BO3, H2BO3, HBO3

Function in the plant

Enzymatic activator
Effect on the pollen tube fertility.


Small leaves, unshaped, light green and tanned color. Symptoms appear firstly in younger leaves since this nutrient has low mobility
Low level of fruit set, then less fruit number and/or unshaped.

Due to its important role at fruit set, and considering that in case of raspberries and blackberries the fruits are compounds (poli drupa), a boron deficit normally generates unshaped fruits. In case of blueberries the main effect is a lower number of fruits. This is a nutrient required in very low quantity, then its application must be carefully done since could pass from deficiency to toxicity.

General considerations for an adequate Berries´ nutrition.

• Provide nutrients in base of expected yields and with an adequate macro and micronutrients.
• Consider cations´ relations: Ca/K, Ca/Mg, (Mg + K)/Ca.
• Apply potassium soluble and chloride free sources.
• Utilize diagnostic tools such as: soil and foliar analysis, suction probes and chlorophyll meters, among others.
• Fraction nutrients´ applications, according to the plant extraction period.
• Apply agronomic principles for a good nutrition through fertirrigation.
Nutritional Recommendation
An adequate supply of nutrients to plants should incorporate both macronutrients and micronutrients. SQM in the selection of specialty plant nutrition (SPN) that offers the following alternatives available according to the route of application (fertigation, soil or foliar):

Agronomic principles for adequate nutrition through fertirrigation

Minimum Law or Liebeg Law: All essential elements are required, in large or low quantities; all have the same importance for the plant. If one of them is lacking or is in low level, limits crop´s growing or production processes.

Vegetal Nutrition characteristics with soluble products to be considered in berries crops:

Solubility: The solubility of crystallized soluble fertilizers is the dissolution capacity of the salt or fertilizer molecule in water. This capacity is related to the chemical and physical composition of the molecule, which intervenes in the dissolution velocity.

Electric conductivity of soluble fertilizers: The electric conductivity (E.C.) is a measurement of the salts´ concentration in a liquid or solid media. As greater saline concentration, the larger is the “conductivity” of electricity, measured by a conductivity meter. All soluble fertilizers have a different E.C. In soluble fertilizers this variable is utilized for determining the salinity generated by the fertilizer in comparison with other fertilizers salts, so to select the most adequate products according each case.

Soluble fertilizers´ pH: As known, pH is a concentration measurement of H+ ions in a solid or liquid media. All fertilizers have different pH in and this parameter is also essential in the soluble fertilizer selection, since in some cases is required soluble fertilizers of acid reaction, in other neutral reaction and in other alkaline reaction, according the soil and crop type.

Nutritional Plan for blueberries with fertirrigation at full production:

Fertirrigation program for Blueberries. Between 6 and 10 ton/ha yield

Phenological Stage

Utilized Product


Nutrients provided (kg/ha)







Sprouting to fruit set

Ultrasol® Multipurpose (18-18-18)







Ultrasol® Calcium (Calcium Nitrate)







Fruit set to harvest

Ultrasol® Production (13-6-40)







Harvest to leaves fall

Ultrasol® Development (18-6-18)







Ultrasol® Calcium (Calcium Nitrate)







Total Supply







Another important concept in the water management that must be considered is the application time, which depends of the infiltration velocity and irrigation frequency. These are determined according the soil type, plant´s phenological stage and crop´s evapotranspiration.

A water excess, as well lack of it, produce a negative effect in the plant’s growing and development processes. The lager water absorption by Berries, under a good water availability conditions, is made closer to the trunk or stem in the first 20 to 30 cm of the soil profile. The water requirements vary according the agro climatic areas.

By morpho-anatomy the blueberry plant lacks of root hairs, which restricts the water absorption capacity, and produces that the specie to be susceptible to damage by drought. Then, it is necessary an adequate moisture level, which will be supplied through the artificial irrigation (drip). The greatest plant’s demands are during the growing period and the fruits´ maturity.
Salinity corresponds to the salts´ concentration contain by the soil or a solution, which is measured through the electric conductivity and is expressed in mmhos/cm. As higher value, the higher is the salts´ concentration in the solution and vice verse.

Berries are in general very sensible crops to high Electric Conductivity (Table 1 and 2); this produces crop damage by a too high salts´ concentration solution, which produces interference in the root absorption. If this occurs, the water absorption is not produced and the plant wilthers.


C.E. (mmhos/cm) in which yield is reduced








Blueberry’s tolerance limits to salinity. - Source: Hirzel y Rodriguez 2003




Salinity (ce)







0,5 a 1,0





Limit tolerance in the soil solution for Blueberry crop. - Source: Fertirrigation on Berries, II Seminary of Fertirrigation, SQMC 2003.
Berries Phenology
For making an adequate nutrition through irrigation, firstly it must be considered the phenology. To place in order each of the stages according to time in each zone. The objective is to know in which period correspond to apply the quantity and nutrients´ type together with water.

Latency : The plant is found in the metabolic recess, which ends after a quantity of cold hours have occurred. There is neither consumption nor internal transport of water and nutrients. Nutrients are part of the chemical compounds´ reserve.
Activation : Ends of latency. An internal transformation of starches to sugars is generated. The nutrients´ mobilization from the roots and wood to the sprouting areas is initiated. The plant is provided by its own reserves. The bud swollen stage is initiated.
Sprouting : The first leaves appear. The plant begins to absorber water and nutrients.
Development : A great cellular activity is produced oriented to the new organs´ formation. The root development is initiated. In this stage Calcium is very important, which form part of the plant structures. Besides, in this period it has greater mobility which differs from other stages when this element has reduced mobility.
Growing : There is an enlargement of organs´ size and an increment of daily water and nutrients´ demand, especially Nitrogen. In this stage there is a high dependence on the external nutrient supply.
Flowering : Nutrients, sugars and water are mobilized towards the reproductive organs; the absorption by the roots is the highest. Potassium is fundamental in this stage due to its role of carbohydrates´ transport, which forms 90% of the fruit dry weight.
Fruit set : The flower pollination occurs and marks the fruit filling initiation.
Fruit filling : This is the process of highest activity in the nutrients´ internal translocation.
Veraison : In this stage the fruit has reached the maximum size and the change in color begins. The fruit becomes to be the principal organ of photosynthates demand.
Harvest : The fruit removal is performed according to commercial parameters.
Post Harvest : The plant presents a root activity and a flow of nutrients towards the roots and wood. This is the key moment for nutrients´ application and to increase the reserves for the growing initiation in the next season.
For obtaining an adequate nutritional plan on berries, it is necessary to know the nutrients’ demand according the quantity and nutrient type. Also, it is important to know the role of each nutrient on the crop’s growing, yield and production quality.
Firmer Bigger and heavier with Speedfol™

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