Foliar silicon application enhances maize agronomic performance under drought stress

Abstract

Drought stress poses a critical threat to maize productivity by impairing physiological processes and yield formation. Silicon (Si) has emerged as a stress-mitigating element due to its ability to improve plant water status, preserve membrane stability, and protect photosynthetic pigments under drought conditions. However, there is a further need to explore the effectiveness of foliar-applied Si in hybrid maize under different drought conditions, especially during the reproductive stage. This pot experiment was conducted during fall 2023 to evaluate the effectiveness of foliar-applied silicon (Si) in mitigating drought-induced damage in hybrid maize. The experiment was arranged in a completely randomized design using a factorial arrangement with three field capacity levels (100%, 80%, and 60% FC) and four silicon concentrations (0, 4, 6, and 8 mM). Drought stress at 60% FC reduced grain yield per plant by 32.7%, thousand-grain weight by 16.3%, relative water content by 23.9%, and chlorophyll a by 46.2% compared with the well-watered control. While foliar application of 8 mM Si alleviated drought effects by increasing grain yield by 30.7%, biological yield by 7.5%, and relative water content by 9.2% compared with untreated plants under 60% FC. Cell membrane injury was reduced by 12.9% with 8 mM Si under severe drought. Significant FC × Si interaction effects were observed for thousand-grain weight, grain yield per plant, biological yield, grain protein content, and grain rows per cob. These findings suggest that, among the tested treatments, foliar application of 8 mM Si was most effective in reducing drought-induced physiological damage and maintaining yield under severe reproductive-stage drought stress.