Unravelling Potential of Silicon and Rhizobacteria in Reducing Cd-related Health Risk in Grazing Animals by Enhancing Maize Fodder Quality

Cadmium (Cd) enrichment in agricultural soils due to wastewater irrigation poses significant risks to the growth, quality, and yield of maize fodder. This study explores the role of SN215 and silicon (Si) in mitigating cadmium (Cd) toxicity in maize fodder and reducing associated health risks in grazing animals. The SN215 strain, isolated from the wheat rhizosphere and identified as SN215, exhibited 83% Cd biosorption efficiency at a medium Cd concentration (10 ppm). Under controlled greenhouse conditions, the combined application of SN215 and Si significantly enhanced maize growth, resulting in a two-fold improvement in shoot fresh and dry biomass. Furthermore, the treatment improved relative water content (RWC), phenolic levels, chlorophyll concentrations, and protein content, restoring RWC to 60% and increasing phenolic content by 10% in comparison to plants under Cd-only stress. The treatment significantly increased antioxidant enzyme activities (ascorbate peroxidase, catalase, superoxide dismutase, and peroxidase) while reducing oxidative stress markers like malondialdehyde and hydrogen peroxide by 61.96% and 59.43%, respectively. Moreover, the combined application of SN215 and Si reduced Cd uptake in shoots by 95% and soil Cd levels by 30%. Health risk assessments revealed a negligible daily intake of metals and a health risk index for grazing animals with SN215 and Si treatment, highlighting its effectiveness in mitigating Cd toxicity. The findings demonstrate the potential of SN215 and Si co-application as an eco-friendly strategy to improve fodder quality and reduce health risks in Cd-contaminated environments.