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This news article was originally written in Spanish. It has been automatically translated for your convenience. Reasonable efforts have been made to provide an accurate translation, however, no automated translation is perfect nor is it intended to replace a human translator. The original article in Spanish can be viewed at Comparativa de las principales fuentes de potasio aplicadas en fertirrigación para la agricultura

Comparative of the main sources of potassium applied in fertirrigación for the agriculture

José Manuel Fontanilla, director of Marketing of Haifa Iberia

06/11/2013
71732
The importance of the potassium for the plants is very known in the world of the agriculture, since it is a macro-essential nutrient for the vegetal growth. The potassium acts like regulator of the pressesure osmótica and is an element irremplazable in the process metabolic of the plants (photosynthesis, synthesis of proteins and carbohydrates). For this reason it is fundamental in the vegetative growth, in the fructificación, in the maduration and in the quality of production of our crops. By all this a suitable contribution of this element is essential to obtain the maximum performance and quality in our harvests.

In agriculture there are three fundamental sources to contribute this essential element by means of the fertilisation, using nitrate potásico (KNO3), sulphate potásico (K2UNDER4) or chloride potásico (KCl). With the end to choose the best source of potassium for our crops go to explain the physical characteristics-chemical of each one of them (Table 1).

Table 1: physical Characteristics-chemical of nitrate of potassium, sulphate of potassium and chloride of potassium...

Table 1: physical Characteristics-chemical of nitrate of potassium, sulphate of potassium and chloride of potassium.

Nutritious value vegetable

The nitrate potásico contains 13% nitrogen (N) and 46% potassium (K2Or). Both are macronutrientes consumed by the plant entirely, not leaving waste of other elements that can be hurtful. The synergistic effect between K+ and NO3- facilitates the absorption of both ions by part of the roots of the plant, increasing the absorption of the same. Besides, the affinity between the nitrate loaded negatively and the potassium loaded positively avoids the absorption of this last to the particles of the floor, doing that it was available for the plants during a more prolonged time.

The sulphate potásico contains 50% of potassium (K2Or) and 54% of sulphate (UNDER4). The relation UNDER4/K2Or that find us in the plants is of 1:20, by what the fertilisation with sulphate potásico leaves considerable quantities of sulphate, in excess, in the solution of the floor. Chloride potásico contains 60% of potassium (K2Or) and 46% of chloride (Cl). The existence of chloride in the solution of the floor affects negatively to the plants. When it increases the concentration of chloride in the solution of the floor, the plants take said chloride instead of the nutrients aniónicos essential, especially the nitrate, affecting the development of the plant. When the quantities of chloride increase produce toxic effects, that can carry to the loss of performances and even to the death of the plant (figure 1).

It appears 1: Effect of the concentration of chloride in the fabric of the tomato in dry weight of the aerial part
It appears 1: Effect of the concentration of chloride in the fabric of the tomato in dry weight of the aerial part.

Solubility

The solubility in water of the nitrate potásico is a lot of elder that the one of the Sulphate potásico (Table 2). Besides, the solubility of the nitrate potásico increases with the increase of temperature of the water, whereas the solubility of the sulphate potásico is almost constant. Another advantage of the nitrate potásico is his rank of dissolution: the nitrate potásico dissolves faster that the Sulphate potásico. The high and fast solubility does of the nitrate potásico an ideal source for the manufacturing of solutions fertilizantes to any temperature.
Table 2. Solubility of the nitrate of potassium compared with sulphate of potassium to different temperatures
Table 2. Solubility of the nitrate of potassium compared with sulphate of potassium to different temperatures.

Compatibility

The nitrate potásico is compatible with all the fertilizantes, whereas the sulphate potásico does not have to mix with fertilizantes that contain calcium, this combination forms precipitated insoluble (plaster) what can block the system of fertirrigación.

Index salino and electrical conductivity

The Index Salino (IS) is a measure of the concentration of salts that induces a fertilizante in the solution of floor (Mortvedt, 2009). To greater index salino of the fertilizante, greater problems of salinity go to have with this.

The IS of a material expresseses like the relation of the increase of the pressesure osmótica produced by a fertilizante specific, with regard to the pressesure osmótica generated by the same weight of nitrate of sodium (NaNO3). The IS of the nitrate of sodium is the index of reference taking a relative value of 100. When it applies beside a seed, fertilizantes with low value of IS will be able to ensure a good germination without problems of proliferation. To equal weight, the nitrate potásico has a value of IS (73,6) minor that the chloride potásico (116,3) (table 1). In addition to IS, exists another indicator used to expresses the potential risk of the salinity in the floor, that is related with the effect of the solution fertilizante on the Electrical Conductivity (CE), to greater CE greater potential risk to produce symptoms by salinity in the crops.

The Electrical Conductivity (CE) of an electrolytic solution is the measure of his skill to drive the electricity. The Nitrate potásico has the lower value of CE (Table 1), compared with other sources of potassium.

Table 3: Effects in the CE of several combinations of fertilizantes, compared with KNO3, keeping constant the levels of N and K...

Table 3: Effects in the CE of several combinations of fertilizantes, compared with KNO3, keeping constant the levels of N and K.

In the table number 3 shows the effect in the CE of several combinations of fertilizantes compared with nitrate potásico when the contributions of N and K keep constants. The replacement of the nitrate potásico by the combinations 2 and 4, resulted in almost 50% of increase of the CE, whereas the combination 3 almost bends the CE of the nitrate potásico. Therefore, the selection of the fertilizante suitable will help to reduce the risks of salinización of floors and the decrease of performance associated, especially when the salts can not be washed through the irrigation.

Conclusions

The importance to contribute free potassium of chloride is very known, since the chlorine is an element that produces fitotoxicidad to the plants, by what the application of chloride potásico like fertilizante would have to limit to some crops tolerantes. Comparing the others two existent sources in the market of potassium the Nitrate potásico offers the following profits:

  • Better alimentary composition for the plant.
  • Better exert like source of K.
  • High solubility and rapidity of dissolution.
  • Wide rank of compatibility with other fertilizantes and agroquímicos.
  • Does not interfere with the absorption of other ions by part of the plants.
  • Minimum effect on the pH of the floor.
  • Low contribution to salinity of floor.

Bibliographic references

  • Mortvedt, J.J. 2009. Calculating salt index.
  • Haifa group Website. http://www.haifa-group.com/
  • Potassium nitrate association website. http://www.kno3.org/

Related Companies or Entities

Haifa Iberia, S.L.
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