2025-07-082025-07-082025Nieto Cantero, J., García López, A.M., Recena Garrido, R., Quintero Ariza, J.M. y Delgado García, A. (2025). Beyond Macronutrients Supply: The Effect of Bio-Based Fertilizers on Iron and Zinc Biofortification of Crops. Agronomy, 15 (6). https://doi.org/10.3390/agronomy150613882073-4395https://hdl.handle.net/11441/175128Iron (Fe) and Zinc (Zn) deficiencies in crops pose indirect problems for human health. The risk of these deficiencies increases with high doses of phosphate fertilizers. Fertilizers obtained through recycling—so-called bio-based fertilizers (BBFs)—can contain significant amounts of Fe and Zn, which can contribute to crop biofortification. Although the use of some organic BBFs has been shown to improve biofortification, an in-depth study on this effect and on the effect of P on Fe and Zn nutrition with the use of different kinds of bio-based P fertilizers is still lacking. A pot experiment with 11 different BBFs was conducted using two soils with different physicochemical properties that affect P, Fe, and Zn dynamics (one rich in CaCO3 and the other rich in Fe oxides) to assess their biofortification effects on wheat and sunflower. Although some BBFs increased Fe concentration in the edible parts, the overall trend was towards an increased P:Fe ratio (up to 62%), which decreased Fe digestibility. On the other hand, all BBFs led to Zn biofortification, with a 27% decrease in the P:Zn ratio in the CaCO3-rich soil, while in the Fe oxide-rich soil, the decrease was up to 61%. The supply of Zn and organic C, as well as the dominant P forms in BBFs, were the main factors explaining Zn biofortification. Bio-based fertilizers also decreased the antagonism between P and Zn and between Fe and Zn. The results demonstrated that the inclusion of BBFs in agrosystems management can contribute to improving the quality of human diets, at least with regard to Zn intake, while also contributing to more sustainable fertilization practices.application/pdfengAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/biofortificationphosphoruscircular economyrecycled fertilizersinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess10.3390/agronomy15061388