A practical assessment of nano-phosphate on soybean (Glycine max) growth and microbiome establishment

Aims - The efficacy of needle-shaped nano-hydroxyapatite (nHA; Ca10(PO4)6(OH)2) as a phosphate (Pi) fertilizer was evaluated as well as its impact on soil and soybean (Glycine max) microbial communities.Methods - Greenhouse experiments were used to evaluate microbial communities in soy fertilized with nHA using16S rRNA high-throughput gene sequencing. Separate growth experiments using agriculturally relevant nHA concentrations and application methods were used to assess plant growth and yield compared with no Pi, soluble Pi, and bulk HA controls.Results - Overall, nHA treatments did not show significantly increased growth, biomass, total plant phosphorus concentrations, or yield compared with no Pi controls. Soil structure and rhizosphere community structures in controls and nHA treatment groups were similar, with minor shifts in the nHA-containing pots comparable to bulk HA controls at equal concentrations.Conclusion - The implementation of nHA in an agriculturally realistic manner and the resulting poor soy growth advises that contrary to some reports under specialized conditions, this nano-fertilizer may not be a viable alternative to traditional Pi fertilizers. To determine if nano-phosphate fertilizers are to live up to their conjectured agricultural potential, alternative nHAs, with differing morphologies, physicochemical properties, and interactions with the soil matrix could be investigated using the evaluative procedures described.