Monopotassium phosphate: tips for correct application
· Valerii Korolko · 7 min read
All recommendations from Prodservis are based exclusively on the example of Prayon Monopotassium Phosphate (MKP), which makes it possible to highlight the particular advantages, quality nuances and technical support that distinguish Prayon fertiliser from other analogues on the market.
Monopotassium phosphate fertiliser from Prayon – what it is and why it is chosen
Prayon Monopotassium Phosphate (MKP) is potassium monophosphate.
Monopotassium phosphate fertiliser:
- Guaranteed product purity
Prayon MKP undergoes multi-stage purification of the raw material, which ensures the absence of insoluble impurities and extraneous salts. Every sample of the product is checked for the absence of chlorides, sodium and heavy metals – this is critically important for crops sensitive to saline ions (berries, ornamentals, seedlings). - High solubility and uniform granule size
Prayon MKP granules are of uniform size, which guarantees fast and even dissolution without sediment. Even in cold water (above +10 °C) Prayon MKP dissolves completely, which significantly speeds up the preparation of working solutions compared with cheap analogues. - Consistent quality from batch to batch
The use of automated production systems guarantees a stable content of P₂O₅ ≈ 52% and K₂O ≈ 34%.
That is why, when it comes to "potassium monophosphate" or "monopotassium phosphate fertiliser", most professional farms prefer Prayon products.
Composition of monopotassium phosphate from Prayon: what is inside
Prayon Monopotassium Phosphate (Prayon MKP) has a stable composition that is carefully calibrated during production:
Phosphorus (P₂O₅ ≈ 52%): a highly available form that underpins energy metabolism, root system development, abundant flowering and the formation of quality seeds. In addition, Prayon checks for the absence of insoluble phosphates (for example, amorphous phosphate), which are sometimes found in low-quality analogues.
Potassium (K₂O ≈ 34%): by optimising water balance, it helps increase stress resistance (drought, disease, temperature fluctuations), improves the quality and appearance of fruit, and promotes the accumulation of beneficial substances. Potassium ions in the form of pure MKP (without sulphate or chloride compounds) provide optimal osmotic potential in the cells, which increases stress resistance. The manufacturer regularly monitors the granulometric composition to prevent agglomeration and uneven dosing.
Absence of impurities: All other salts (Cl⁻, Na⁺, SO₄²⁻) are controlled at below 0.5%, which makes Prayon MKP safe for soils with a high level of salinity and for sensitive crops. As a result, you get a "monopotassium phosphate fertiliser" with a guaranteed absence of side ions that can affect the pH of the solution or cause burns. It is this stable combination of components that explains why the "application of monopotassium phosphate" from Prayon gives the maximum effect in laboratory and field tests.
How to apply monopotassium phosphate from Prayon correctly: use and frequency
Application of monopotassium phosphate (the rates given are adapted to the high solubility and purity of the product)
Application forms of Prayon MKP
- Foliar feeding
For spraying, a solution with a concentration of 0.2–0.4% (the risk of sediment forming on the leaf surface is eliminated); thanks to the uniform granule size of Prayon, the spraying system stays clean and is not blocked by crystals. - Soil feeding (drip irrigation, fertigation)
For irrigation through a drip or fertigation system: 1–1.5 kg of Prayon MKP/ha per cycle (300–500 l of water). Thanks to the absence of calcium and magnesium, Prayon MKP does not cause precipitation in pipes and filters, which is often observed with cheap ammonia or nitrophosphate complexes. - Hydroponics and aeroponics
A source of phosphorus and potassium for closed systems (concentration 0.5–2 mM). Thanks to the stable composition, the solutions do not change their electrical conductivity (EC) for 24–36 hours, which is especially important for precise control of nutrition.
Timing and frequency of feeding
- "Green bud" phase and budding
The first foliar spraying with Prayon MKP at a concentration of 0.3% at the "green bud" phase. Thanks to the increased phosphorus concentration, plants form flower-bearing generative organs more actively. The second treatment 10–14 days later (after the start of budding) with the concentration reduced to 0.2% – to stimulate fruit set with minimal risk of burns. - Fruit filling phase
Application of Prayon MKP through drip irrigation (1.2 kg/ha) in the middle of the filling phase ensures an optimal level of K₂O, which increases the dry matter content of the fruit. The last foliar feeding with Prayon MKP (0.2%) is carried out no later than 14 days before harvest, to avoid the accumulation of residues on the fruit and reduce the risk of burns during hot days.
Optimal conditions for application
- Air temperature: +15…+25 °C. At low temperatures (< +10 °C) the penetration and absorption of ions by the leaves deteriorates, so Prayon recommends postponing treatments until it warms up.
- Humidity: medium (50–70%). It is better to spray in the morning hours (avoiding morning dew) or late in the evening, after the sun has set, so that the product has enough time to be absorbed without the risk of burns.
- Water characteristics: Prayon MKP shows no sediment even in moderately hard water.
What monopotassium phosphate from Prayon can and cannot be combined with
When using Prayon MKP, it is important to take compatibility with other products into account.
Compatible combinations
- Insecticides and fungicides
Prayon MKP combines well with most popular insecticides and fungicides that have a neutral or slightly acidic reaction (pH 5.0–6.5). Thanks to the pH control of Prayon MKP, the tank mix remains stable even when a pesticide of medium solubility is added. - Micronutrient fertilisers
Prayon MKP combines easily with trace elements in chelated form (EDTA/Zn, EDTA/Fe, EDTA/B), since a stable ionic balance is maintained in the tank mix. If micronutrient fertilisers need to be added, Prayon's "monopotassium phosphate fertiliser" is dissolved first, and only then are the trace elements introduced, in order to avoid a temporary decrease in solubility. - Organic stimulants and biostimulants
Prayon MKP can be combined with biostimulants based on humic acids, as well as with seaweed extracts. Thanks to pH control, there will be no interaction that leads to sediment or a change in the colour of the solution.
Incompatible combinations
- Water-soluble calcium products
When Prayon MKP is mixed with calcium sulphate or calcium nitrate, an insoluble Ca₃(PO₄)₂ precipitate may form, so we recommend applying calcium fertilisers separately. - Highly alkaline products can partially neutralise the phosphate acidity of Prayon MKP, which will reduce phosphorus availability. If an alkaline product must be used, carry out two separate treatments on different days.
Mistakes when using monopotassium phosphate from Prayon – how to avoid harm
Even a premium-class "monopotassium phosphate fertiliser" from Prayon can lead to negative consequences if certain nuances are not taken into account. Below is a list of typical mistakes when working with Prayon MKP and tips on how to avoid them.
Incorrect dosage
- Exceeding the recommended concentration leads to a sharp local drop in pH (to 4.2–4.5), which can cause leaf burns even in frost-resistant varieties.
- Insufficient mixing
If Prayon MKP is not completely dissolved, some of the granules may settle at the bottom of the container. During treatment this leads to uneven dosing, burning of growth points or insufficient nutrition of certain parts of the root system.
Treatment in unfavourable conditions
- High temperature and bright sun
If Prayon MKP is sprayed on a sunny day (+28…+35 °C) at midday, the working solution evaporates quickly, and crystal residues on the leaf surface cause micro-burns. - Before rain
Although Prayon MKP dissolves well and penetrates leaf tissue within 2–3 hours, rain falling within 6–8 hours after treatment can wash off about 30–40% of the active substance.
Ignoring the results of soil and leaf analysis
- If there is an excess of phosphorus or potassium in the soil, additional application of Prayon MKP can lead to the accumulation of salts in the root zone. This reduces water uptake and causes chlorosis. Before applying Prayon MKP, be sure to take the results of agrochemical analysis into account and combine it with calcium-magnesium products in the off-season (but not in the same tank).
- Mismatch with growth phases: applying Prayon MKP every week regardless of the crop development phase leads to the accumulation of deposits in the plant's vessels and disrupts the micronutrient balance.
Storage and loss of product quality: at humidity above 70%, Prayon MKP can cake and lose granule uniformity. This complicates dosing and increases the risk of deposits in equipment.
By avoiding these mistakes, you will always get the maximum efficiency from the application of monopotassium phosphate, specifically from Prayon products.
Thus, all the nuances of Prayon's "potassium monophosphate" come down to three key points: unquestionable quality from a European manufacturer, high solubility and a guaranteed result. It is these factors that make Prayon MKP the benchmark for those who strive for maximum efficiency in a plant nutrition programme.
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