Foliar application of iron-based nanofertilizers to wheat grown in a Cd-contaminated field: implications for food safety and biofortification

Abstract

Nanotechnology applications in agriculture have received considerable attention with the aim of improving crop production, nutritional quality and food safety. The comparative effects of four different iron-based nanomaterials (Fe NMs, 50 mg Fe L⁻¹) on wheat were investigated following foliar application in a Cd-contaminated field trial. The results showed that α-Fe₂O₃ NMs, γ-Fe₂O₃ NMs and Fe₃O₄ NMs significantly reduced the Cd concentration in wheat grain (by 60.9%, 44.7% and 50.1%, respectively) below the established Cd safety threshold (0.1 mg kg⁻¹), but only γ-Fe₂O₃ NMs could simultaneously improve grain yield (by 8.6%) and the PA/Fe molar ratio in white flour (17.9%) compared to the control. Furthermore, α-Fe₂O₃, γ-Fe₂O₃ and Fe₃O₄ NMs significantly lowered the dietary Cd exposure and health risk by 44.2–57.9% by reducing Cd concentrations and bioaccessibility in wheat flour. The ionomic analysis demonstrated that with the exception of nZVI, elemental homeostasis was more sensitive to Fe NMs in the wheat leaf and glume, and a significant negative correlation between Cd and P, as well as Mo and Ca were observed. Overall, these findings highlight the significant potential of γ-Fe₂O₃ NMs as an effective foliar agent for safe wheat production and biofortification in nano-enabled agriculture.