Nano-hydroxyapatite increased soil quality and boosted beneficial soil microbes

Abstract

Nano-hydroxyapatite (nano-HA) is a promising phosphorus nanofertilizer to be applied in agriculture. Understanding their environmental implications is important for their safe and sustainable use. In this study, maize plants were cultivated in soil amended with nano-HA at 150 mg P per kg soil for 4 weeks. The impacts of nano-HA on plant growth, soil quality, and soil microbial communities were investigated. Nano-HA significantly increased fresh biomass, the content of bioavailable phosphorus, and chlorophyll content of maize plants, indicating the positive effects of nano-HA on plant growth. In addition, nano-HA increased soil quality by increasing soil bioavailable P (12.7-fold), electrical conductivity (EC) (28.7%) and soil organic matter (SOM) (15.6%). Gas chromatography–mass spectrometry (GC–MS) based soil metabolomics revealed that nano-HA increased the content of many low molecular weight metabolites in soil, e.g., sugar and sugar alcohols ( D -arabinose, L -arabitol, palatinitol, and sorbitol), amino acids ( L -tyrosine), and phenolic acids (catechin and scopoletin). The sequencing of 16S rRNA reveals that nano-HA exposure didn’t alter the richness of soil microbial communities. However, nano-HA induced a shift in soil bacterial community structure; groups related to plant growth-promoting rhizobacteria (PGPR), especially P solubilizing bacteria (PSB), e.g., Burkholderiaceae , Massilia , Sinomonas , and Streptomyces have been increased . The results of this study provide a holistic evaluation of the effects of nano-HA on plant growth and soil health.