Effect of Nutrient Forms in Foliar Fertilizers on the Growth and Biofortification of Maize on Different Soil Types

This research aimed to evaluate how different chemical forms of key nutrients, delivered through an advanced foliar product (PRO) and a standard formulation (TRA), influence maize performance when grown on contrasting soil types. Each fertilizer provided a set of macro- and micronutrients, including nitrogen, phosphorus, potassium, boron, copper, iron, manganese, molybdenum, and zinc, along with trace elements such as chromium, iodine, lithium, and selenium. In TRA, Fe and Zn were complexed with EDTA, and trace elements were present in mineral form. In PRO, Fe and Zn were chelated with amino acids, and trace elements were bound to plant extracts. The study examined increasing doses of PRO and their potential toxicity. Both fertilizers improved maize biomass: fresh weight increased by 5–8% and dry weight by 8–14%, depending on the dose. At the lowest dose, yields were similar. However, PRO was more effective in biofortifying maize with iron and zinc on sandy soil, increasing levels by 16% and 7% compared to TRA at the lowest dose and up to 29% at the highest dose. PRO was well tolerated at higher doses. No significant differences were observed between the second and third doses of PRO, suggesting reduced efficacy at the highest dose.