Performance of Moringa Oleifera Extract-Fe/Zn Nanoparticles in Mitigation of Drought Stress and Improving the Physiological Parameters and Yield in Sweet Corn (Zea mays L. var. Saccharata)

This study investigated the effects of Moringa oleifera leaf extract (M), nanoparticles of iron oxide (FeNP) and zinc oxide (ZnNP), and nanocomposite of Moringa extract + Fe/Zn nanoparticles (M + FeNP + ZnNP) on physiological responses and grain yield of sweet corn (Zea mays L. var. saccharata) under drought stress during the 2024–2025 growing seasons in Babil, Iraq. Experiments were conducted as a split-plot arrangement in a randomized complete block design with three replications. The main plots consisted of three drought stress levels: no stress (100% field capacity, FC), moderate stress (75% FC), and severe stress (50% FC), while the subplots comprised M, FeNP, ZnNP, and M + FeNP + ZnNP treatments. Among all treatments, the Moringa-based Fe/Zn nanocomposite (M + FeNP + ZnNP) was the most effective in mitigating drought-induced damage. Compared with the control, it increased relative water content (RWC) by 70.8%, proline content by 84.4%, superoxide dismutase (SOD) activity by 72.2%, and catalase (CAT) activity by 79.1%, while reducing thiobarbituric acid reactive substance (TBARS) content by 64.3%. It also preserved chlorophyll (Chl) a, Chl b, and photosystem II efficiency (Fv/Fm), resulting in a 28.1% increase in leaf area index (LAI) and a 112% increase in grain yield under severe drought stress. These findings demonstrate that the application of a Moringa-based Fe/Zn nanocomposite is a sustainable and effective strategy for enhancing drought tolerance and maintaining grain yield in sweet corn under water-limited conditions.