Effects of Soil pH and Coatings on the Efficacy of Polymer coated ZnO Nanoparticulate fertilizers in Wheat (Triticum aestivum).

This study used ZnO nanoparticles (NPs) as seed treatments and as soil amendments to enhance Zn concentrations in wheat grain. In the seed treatment experiment, seeds were treated with dextran coated (DEX-ZnO) and bare ZnO NP suspensions, in addition to ZnSO4, at 500 mg Zn/L. In the soil amendment experiment, soil pH was adjusted to 6 and 8, then soils were spiked with 15 mg Zn/kg soil in the form of DEX-ZnO and bare ZnO NPs, as well as ZnSO4. For the seed treatment, ZnO NPs resulted in significantly higher grain Zn concentration 96.9 ± 25.4 compared to (72.2 ± 25.4), (78.3 ± 24.3), and (81.0 ± 19.4) mg Zn/kg in the control, ZnSO4, and DEX-ZnO NPs treatments, respectively. In the soil amendment experiment, grain Zn concentrations were the same across all Zn treatments regardless of soil pH. Plants grown at pH 6 had higher Zn accumulation and leaf and stem biomass compared to pH 8. This study demonstrates that treatment of seeds with ZnO NPs can enhance Zn content of grain using far less Zn than is typically used for soil amendments. This may help reduce the environmental impact of Zn fertilization.