Plants absorb P as Orthophosphate ions H2P04- and HP042- Polyphosphates are a chain link molecule of orthos and are not available to the plant until conversion.
Orthophosphates
Polyphosphates
Immediately usable
The form of Phosphorus taken up by the plant
High purity
Higher investment
Neutral pH
Higher levels of impurities
Not immediately available
Must convert in soil to the Orthophosphate before the plant can use it
Good carrier for micronutrients
Less expensive
Source: Farm Facts –Phosphorous fertilization in crop production and TVA.
Polyphosphate Production
Super Phosphoric Acid (SPA) combined with NH3 Processed through a Pipe Reactor = 10-34-0 or 11-37-0
Chain Link Molecule of Orthophosphate
Unavailable to the plant in that form
Must convert to orthophosphate
Time and Temperature
ALPINE Production
White and Green Orthophosphate acid, KOH, Aqua Ammonia, APP and water
Chemically combined to form MKP, DKP, MAP and DAP
Hot mix reaction – Chemically combining the raw materials