Improving nutritional values and yield in common bean (Phaseolus vulgaris L.) cultivars via foliar application of zinc and iron fertilizers

Developing countries struggle to achieve food security due to a lack of superior crop cultivars, limited inputs, and environmental degradation. One way to deal with these issues is to biofortify with zinc- (Zn) and iron (Fe)-containing fertilizers to improve nutrient content and productivity. Thus, this study aims to assess the effect of foliar application of Zn and Fe fertilizers on various bean cultivars. Three cultivars (SAB-632, DAB-197, and BZ-2) combined with nine Zn- and Fe-containing fertilizers (T1 = 0, T2 = 0+1.5%, T3 = 0+3%, T4 = 0.5%+0, T5 = 0.5%+1.5%, T6 = 0.5%+3%, T7 = 1%+0, T8 = 1%+1.5%, and T9 = 1%+3%) were used as experimental treatments. The study utilized a split-plot design with a factorial arrangement and three replications, with cultivars on the main plot and fertilizer treatments on the sub-plots. The result revealed that T8 with the cultivar SAB-632 had a significantly higher (17.2%) grain Zn concentration than the control. The cultivar SAB-632 exhibited significantly higher Zn and Fe accumulations. Grain Zn and Fe accumulation were significantly enhanced by the foliar application of treatments, either individually or combined. T6 showed the highest accumulation of Zn and Fe, followed by T9. These values were increased by 33.4% and 29.2%, respectively, due to T6 compared to the control treatment. Additionally, applying these treatments to the leaves improved most agronomic parameters. Therefore, using foliar Zn + Fe fertilizers in bean cultivation can increase essential nutrient contents in grains and improve productivity, ensuring food security and nutrition for small-scale farmers.