MKP vs MAP Fertilizer: Compare the Nutrient Recipe Before Substitution

MKP and MAP both supply phosphorus, but they are not equivalent fertilizer ingredients. Monopotassium phosphate adds potassium; monoammonium phosphate adds ammonium nitrogen. Replacing one by the same delivered mass changes the nutrient recipe. MOS lists monoammonium phosphate (MAP) and monopotassium phosphate (MKP) separately. Select the offered grade and test it in the intended formulation; a catalogue name alone does not qualify a substitution.

Start with the nutrient that the recipe can accept

Haifa’s technical fertilizer overview identifies MKP as a phosphorus/potassium source and MAP as a phosphorus/nitrogen source. The practical purchasing question is whether the formula needs potassium, ammonium nitrogen, or a constrained contribution of either. That decision belongs to the complete nutrient plan and application conditions. It is not a universal recommendation for a crop stage, and it does not establish the nutrient analysis of a MOS batch.

Compare on a defined basis, then rebalance the formula

Ask whether phosphorus is reported as elemental P or as the conventional P₂O₅ equivalent. Likewise, potassium may be reported using a K₂O equivalent. These reporting conventions should not be mistaken for the chemical species in the bag. Confirm assay, moisture basis and units before calculating the amount of each offered grade needed for a common phosphorus input.

Matching that input is only the first calculation. Review the changed potassium and ammonium-nitrogen contribution, and the companion nutrient salts and total stock concentration. Have the responsible formulation or agronomy team approve the revised recipe. Do not infer equal behavior from equal phosphorus or equal bag weight. This guide gives no replacement ratio, application dose or crop-performance guarantee.

A soluble ingredient still needs a stock-solution trial

Test a representative lot with the actual water and complete recipe. Record concentration, preparation temperature, mixing sequence and observation period; compare dissolution, residue and clarity or sediment against agreed acceptance criteria. A dilute jar test does not qualify a much more concentrated stock or different water. Haifa’s dissolution guidance separates incompatible stock ingredients; review calcium-containing concentrates separately from phosphate concentrates rather than assume one clear solution can be stored indefinitely.

Ask the supplier to confirm the intended grade’s impurity and water-insoluble limits and the relevant test methods. If the catalogue’s specification rows do not clearly link a value, unit and grade, request the original TDS and lot COA. Do not reconstruct a purity, pH range or storage claim from disconnected entries. Handle samples under the actual SDS and site procedure.

Request the grade and evidence needed for the RFQ

Begin at the MAP Product page and include the MKP alternative page when asking for a nutrient-source comparison. Provide the fertilizer application, required grade, existing recipe or nutrient constraints, water analysis, stock concentration and sample acceptance method. Include order quantity, annual demand, packaging and destination; request current TDS/SDS, lot COA and a representative sample. Ask the supplier to confirm actual grade specifications and availability before committing. The article does not promise purity, compatibility, certification, MOQ or delivery.