Microorganisms in Biostimulants

ABSTRACT

In March 2016, the EU Commission presented a proposal for new regulations on fertilising material. The regulation includes product rules for a wide range of organic and inorganic products. Microbial biostimulants is one of the categories of products that are included. Biostimulants, in the draft EU regulation, are defined as fertilising materials that affect nutrient processes independently of the product's own nutrient content and with the purpose of improving nutrient utilisation, tolerance for abiotic stress or quality of the crop. Positive list in which species of these bacterial genera are listed Azotobacter spp, Rhizobium spp., Azospirillum spp and Mycorrhizal fungi are a part of the regulation. Since the import and use of these organisms are the responsibility of both the Norwegian Food Safety Authority and the Norwegian Environment Agency, they asked VKM to submit a joint report on effects on health (humans, plants and animals), biodiversity and dispersal, quality of agricultural land and on soil environment. Conclusions: Health risks Based upon our literature review, we have found no indication of any specific diseases in plants, animals or humans induced by the discussed microorganisms. A few reported cases of human disease are caused through wound infections or injections in immunocompromised patients. These represent a situation where any microorganism may induce infections and is not specific for the agents discussed in this report. In summary, the risk of any disease caused by the discussed microorganisms is considered negligible. Environmental risks In soil the biodiversity, competition, adaptation and functional redundancy of microorganisms are extremely high. This means that introduced microorganisms have a very small chance for establishing, and even less so for affecting biodiversity and soil functioning. Introduction of nitrogen fixing species or fungi that can transport P to plants (mycorrhiza) will lead to an increase in the primary production. However, even a large increased activity for these processes will not outcompete naturally occurring symbiotic N-fixation or growth of inherently non-mycorrhizal plant species. Thus, the risks associated with introduced non-pathogenic microorganisms are very low.