According to the invention, the process for the preparation of an enriching agent based on algae of the wrack type (seaweed) consists in placing the algae in a silo, in introducing therein small crustaceae of the Talitrus genus, more commonly called "sand fleas" and in stopping up the silo so as to prevent escape of the crustaceae of the Talitrus genus. The product obtained, the result of the digestion of the seaweed by the crustaceae of the Talitrus genus, is dried and reduced to a powdery form in order to be used as a fertilising substance, or enriching agent, in agriculture or horticulture.
