Iron (Fe) Biofortification Using Fe‐Aminochelates in Sunflower Growing in Calcareous Soils

ABSTRACT Background Efficient agronomic approaches should be developed to alleviate iron (Fe) deficiency in lime‐rich soils. Aims The present study aimed to investigate the efficiency of eco‐friendly synthesized Fe‐aminochelates in remediating Fe deficiency and improving the yield and nutritional quality of sunflower ( Helianthus annuus L.), compared to FeSO₄ in calcareous soil. Methods Fe (glycine) 2 [Fe (Gly) 2 ] and Fe (methionine) 2 [Fe (Met) 2 ] aminochelates were synthesized and characterized via a CHN analyzer, H 1 NMR and FT‐IR spectroscopy. In a field experiment, Fe‐aminochelates and FeSO₄ were applied using three methods (priming, fertigation, and foliar spray) at various plant growth stages. Results The application of [Fe (Gly) 2 ] and [Fe (Met) 2 ] through different methods significantly improved the biomass yield, nutritional quality, and yield attributes, compared with those of FeSO 4 . Compared with the control, foliar application of [Fe (Met) 2 ] increased seed yield (73.9%), oil yield (125.8%), and seed protein content (60%). In addition, antioxidant enzyme activities, total soluble protein (TSP), and seed nutrients such as Fe, N, and S concentrations, as well as the Fe concentration in leaves, also increased in response to [Fe (Gly) 2 ] and [Fe (Met) 2 ] application, whereas the N/S ratio decreased with increasing seed oil content. Conclusions These results suggest that the application of Fe‐aminochelates may be a promising way to promote Fe biofortification and overcome Fe deficiency under calcareous conditions.