User:Xmlrein/sandbox

Composition
Paul Szpak has co-authored several journal articles claiming that seabird guano consists of nitrogen-rich ammonium nitrate and urate, phosphates, as well as some earth salts and impurities, and that unleached guano from favored locales, such as the Chincha Islands off the coast of Peru, typically contains 8 to 16 percent nitrogen (the majority of which is uric acid), 8 to 12 percent equivalent phosphoric acid, and 2 to 3 percent equivalent potash.

However, The Association of American Plant Food Control Officers (AAPFCO) defines Seabird guano as the hardened excrement from marine birds, which contains no organic matter or nitrogen and is a source of phosphates P2O5: "P- Hydroxylapatite - is a naturally-formed phosphate rock mineral with the formula Ca5(PO4)3(OH). The Fluorine content is less than 1%."