A large coarse seaweed occurring chiefly off the coast of California. It is a type of algae and is mechanically harvested by specially equipped barges. Dried kelp contains 2–4% ammonia, 1–2% phosphoric acid, 15–20% potash, and traces of iodine.
Use:
Fertilizers, plastics and conversion to methane by microorganisms; permissible chewing-gum base.