EU regulation 2019/1009 lays down the provisions concerning the placing on the market of fertilizer products in the EU. And it defines a fertilizer product as: a substance, mixture, microorganism or any other material applied or intended to be applied to plants or their rhizosphere, fungi or their mycosphere, or intended to constitute the rhizosphere or mycosphere, by itself or mixed with other materials, in order to provide nutrients to plants or fungi or to improve their nutritional efficiency.
As for biostimulant products of group C6, it defines them as “fertilizer product whose function is to stimulate plant nutrition processes independently of the nutrient content of the product, with the sole purpose of improving one or more of the following characteristics of plants and their rhizosphere:
• nutrient use efficiency,
• tolerance to abiotic stress,
• quality characteristics or
• availability of immobilized nutrients in the soil and rhizosphere.
The European Regulation only allows the use of u types of microorganisms to formulate biostimulants:
• Bacteria of the genus Azotobacter
• Mycorrhizal fungi
• Bacteria of the genus Rhizobium, and
• Bacteria of the genus Azospirillum
The characteristics of biostimulant products must be demonstrated through officially recognized tests in order to be marketed. In other words, in order to be officially registered, the product must be accompanied by a report defining the object of the trial (one of the four previous activities in a more specific way), a description of the fertilizer product, a description of the trials carried out to demonstrate its efficiency with data taken in the field, semi-field or greenhouse, statistical treatment and conclusions.