Fish Liquid Fertilizers: How are they Made?
Tuesday, July 28th, 2009What fish and parts of the fish are used for making fish fertilizer? By-products or waste materials from various types of fish are used. And although technically several varieties of fish can be used, mostly Menhaden fish that contain few amounts of meat and used for making animal feed are used.
The first step is to cook the fish and to squeeze its juice and oils by pressing. The oil is removed while the leftover solids can be ground and baked into protein meals and fed to animals. The juice of the fish is brought to a boil until it becomes more concentrated and results in a fish emulsion.
A small amount of phosphoric acid is added to the fish emulsion to lower the pH. Lowering the pH makes the liquid fertilizer more acidic, which prevents it from decaying and fermenting into gas. Before phosphoric acid was added in the manufacturing process, containers of fish emulsion were known to burst from fermentation. Because the amount of added phosphoric acid is so small (less than one percent by weight), the product is still considered organic.