Mono Ammonium Phosphate (MAP) is a primary source of phosphate (PO4-) in the dry form. It also has some Nitrogen in the NH4 form. MAP is an ortho-phosphate salt that is 82% water soluble, 17% citrate soluble, and has a pH of 4.2. MAP is made from organic origin rock which is mined, ground, and treated with Sulfuric Acid. (One ton of sulfur is consumed to produce one ton of Phosphate). The product of this process is Phosphoric Acid which is then reacted with NH3 to form Mono Ammonium Phosphate. MAP is produced in the USA and several other countries such as Morocco, Saudi Arabia, Jordan, and China.
MAP, being primarily ortho and water soluble makes it highly reactive and susceptible to tie up in high Calcareous and high pH soils. However, this reactivity also makes it a relatively good starter. When applying MAP to soils in the western cornbelt adding a some Sulfur could extend the available life of MAP .
Phosphate is one of the “Big 3” macro nutrients. Nitrogen and Potassium being the other two. Phosphate is critical for root and seed production. However, every living cell on the planet, including plants and animals, requires phosphate to survive. It is used primarily as an energy transfer molecule at the cell level. It forms ATP – ADP . Phosphate removal by a 200 bushel corn crop is 70 lbs of P2O5 or .35 - .4 lbs P2O5 per Bu.
Phosphate rock reserves worldwide have been depleted and we are now mining lesser quality rock, coupled with sulfur becoming in short supply, allows for increased prices from years past.
Contact your Poole Ag representative for the latest supply and price information.