The term “Guano” applies to natural mineral deposits consisting of excrements, eggshells and carcasses of dead seabirds found in almost rainless, hot-dry climatic regions and corresponding fertilizers. Guanos are classified according to age, genesis, geographical origin and chemical composition. Main types are nitrogen- and phosphate Guanos. Phosphate Guanos require a calcareous subsoil for the development, while nitrogen Guanos are formed only under the special climatic conditions of the subtropical-edge tropical high pressure belt with coastal deserts. The most significant nitrogen Guano is the Peru-Guano, which has been used over 2000 years as agricultural fertilizer in Peru. In Europe the application of Guano as fertilizer emerged in the 1840 as “Guano boom” and lasted until the early twentieth century when Guano was replaced by industrial manufactured fertilizers. Only a small quantity is still exported to Europe as additive to organic/mineral fertilizers, more for image boosting than for effect.
Part of the book: Seabirds