Rhizospheric organic acids as biostimulants: interactions with soil borne microorganisms and effect on soil biochemical properties

The biostimulant potential of three different organic acids present in the rhizosphere, specifically lactic, oxalic and citric acids, has been studied. The results showed a rapid and complete metabolism of these three acids, which were used as a source of carbon and energy by soil microorganisms. Regarding to microbiota composition, amplicon sequencing of the 16S rRNA gene showed changes in the structure of soil microbial communities. Application of organic acids produced a decrease in richness and diversity indices inducing the proliferation of microorganisms involved in their degradation. Thus, the structure of the microbiological communities changed in a specific way for each acid. This study presents evidence supporting the use of organic acids as potential soil fertility inducers, by their effects enhancing dominance of PGPB and by stimulating soil microbial activity.