Akbar Soliemanzadeh;Majid Fekr

Department of Soil Science, College of Agriculture, Shahid Bahonar University of Kerman, Kerman 7718897111 (Iran);Department of Soil Science, College of Agriculture, Shahid Bahonar University of Kerman, Kerman 7718897111 (Iran

fe nps;green;fe;calcareous soils;iron nanoparticles;extract

Green iron nanoparticles (Fe NPs) can be a practical solution to combat iron (Fe) deficiency in calcareous agricultural soils. The main aim of the present work was to assess the effects of green Fe NPs on Fe availability in calcareous soils. For this purpose, green Fe NPs were synthesized using green tea (G-Fe NPs), Shirazi thyme (T-Fe NPs), walnut green hull (W-Fe NPs), and pistachio green hull (P-Fe NPs) extracts and applied as a source of Fe fertilizer to sorghum (Sorghum bicolor L. Moench) plants. Results of X-ray diffraction (XRD), scanning electron microscopy (SEM), and dynamic light scattering (DLS) indicated that the green Fe NPs were amorphous in nature and the polyphenols obtained from plant-part extracts acted as both capping and reducing agents. Similar to the behavior of Fe-ethylenediamine-N,N′-bis(2-hydroxyphenyl) acetic acid (Fe-EDDHA) in calcareous soils, G-Fe NPs, T-Fe NPs, W-Fe NPs, and P-Fe NPs increased Fe release compared with the control and FeSO4 treatment. Cumulative Fe release data fitted well to the power function, intra-particle diffusion, and Elovich kinetic models. According to the pot experiment, the increment in soil Fe availability upon Fe-EDDHA and Fe NPs application led to an increase in Fe uptake, growth, and photosynthetic pigment contents of the sorghum plants. Although further research is needed to evaluate the residual effect and environmental impact of green Fe NPs, they may be an appropriate substitute for traditional Fe fertilizers in calcareous soils.