Synthetic apatite nanoparticles as a phosphorus fertilizer for soybean (Glycine max)

TLDR

Some soluble phosphate salts used as effective phosphorus fertilizers cause surface water eutrophication, whereas solid phosphates are less effective, and synthetic apatite nanoparticles could supply sufficient P to crops with reduced environmental mobility and lower bioavailability to algae. The study evaluated the fertilizing effect of synthetic apatite nanoparticles on soybean in a greenhouse experiment. The nanoparticles were synthesized via a one‑step wet‑chemical method, yielding spherical hydroxyapatite particles with a mean diameter of 15.8 ± 7.4 nm. Application of the nanoparticles increased soybean growth rate by 32.6 % and seed yield by 20.4 % versus a regular P fertilizer, while above‑ground biomass rose 18.2 % and below‑ground biomass 41.2 %, indicating that apatite nanoparticles can enhance agronomic yield and reduce eutrophication risk.

Abstract

Some soluble phosphate salts, heavily used in agriculture as highly effective phosphorus (P) fertilizers, cause surface water eutrophication, while solid phosphates are less effective in supplying the nutrient P. In contrast, synthetic apatite nanoparticles could hypothetically supply sufficient P nutrients to crops but with less mobility in the environment and with less bioavailable P to algae in comparison to the soluble counterparts. Thus, a greenhouse experiment was conducted to assess the fertilizing effect of synthetic apatite nanoparticles on soybean (Glycine max). The particles, prepared using one-step wet chemical method, were spherical in shape with diameters of 15.8 ± 7.4 nm and the chemical composition was pure hydroxyapatite. The data show that application of the nanoparticles increased the growth rate and seed yield by 32.6% and 20.4%, respectively, compared to those of soybeans treated with a regular P fertilizer (Ca(H2PO4)2). Biomass productions were enhanced by 18.2% (above-ground) and 41.2% (below-ground). Using apatite nanoparticles as a new class of P fertilizer can potentially enhance agronomical yield and reduce risks of water eutrophication.