Effects of nanofertilizer and nano-plant hormone on soil chemical properties and microbial community in two different soil types

Application of nanotechnology in agriculture has been expanded to improve crop production. The impact of nanomaterials (NMs) on factors that influence the survival and function of beneficial microorganisms is a less studied aspect that needs to be better understood. Only a few studies have assessed the effects of NMs on beneficial soil microorganisms. This study was conducted to assess the effects of nanofertilizer FertiGroe® N (FG-N) and nano-plant hormone HormoGroe® auxin (HG-A) on the chemical properties and microbial communities of two contrasting soils, Lipa clay loam (CL) and Sariaya sandy loam (SL), over a 35-d incubation period in the laboratory. Bacterial and fungal communities were evaluated using amplicon sequencing analysis within the 16S and internal transcribed spacer regions, respectively. The application of FG-N significantly decreased soil pH, but did not affect total N and available P for both soil types. A significant increase in exchangeable K was observed only in Lipa CL. The application of HG-A had no significant effect on soil chemical properties. Regarding the bacterial community after incubation, the relative abundances of Acidobacteriia, Chthonomonadetes, and Saccharimonadia decreased, whereas Acidimicrobiia, Chloroflexia, and Gemmatimonadetes increased with FG-N application in Lipa CL. The application of HG-A increased the relative abundance of Rubrobacteria, Chthonomonadetes, and Chloroflexia in Lipa CL. For the fungal community, FG-N application increased the relative abundance of Sordariomycetes, Agaricomycetes, and Eurotiomycetes, whereas Dothideomycetes and Mortierellomycetes decreased in Lipa CL after incubation. In Sariaya SL, FG-N application increased the relative abundance of Dothideomycetes, Eurotiomycetes, and Mortierellomycetes, but decreased that of Sordariomycetes and Agaricomycetes. Fungal classes observed in the control samples were not detected in the HG-A treatment, but were recovered after incubation in Lipa CL. The microbial diversity in both soil types showed slight changes with FG-N and HG-A application. Principal coordinate analysis illustrated the clustering of bacterial and fungal taxa between Lipa CL and Sariaya SL. Pearson correlation analysis showed that several bacterial and fungal communities were positively or negatively correlated with soil pH. The results suggest that FG-N can be safely used in crop production and HG-A may be used mainly for vegetative propagation.