Silicon and Biochar Synergistically Stimulate Nutrients Uptake, Photosynthetic Pigments, Gaseous Exchange and Oxidative Defense to Improve Maize Growth Under Salinity

Numerous challenges arise in plants, particularly salt-sensitive species such as maize, as a result of salinity. The effectiveness of silicon (Si) and biochar has been recognized in alleviating salt-induced stress. Combined application of Si and biochar could be an effective approach for mitigating drastic effects of salinity on crop plants as compared to their sole application. Hence, the present investigation aimed to assess the effects of combining Si (100 mg kg −1 ) and biochar (1%) on nutrient uptake, concentration of chlorophyll, antioxidant activities, and growth of maize. Present study was conducted using potted maize plants cultivated in sandy clay loam soil, with irrigation carried out using both saline and tap water. The integrated use of Si and biochar was effective in enhancing maize growth under normal and saline conditions. Silicon and biochar synergistically optimized reduction in sodium uptake and improved the accumulation of nutrients including potassium, phosphorus, and nitrogen in roots and shoots, as well as concentration of carotenoids and chlorophyll (a, b, and total). The combined application of both treatments also resulted in increased rate of transpiration and stomatal conductance, while reducing the activities of superoxide dismutase and peroxidase. Consequently, these observed improvements in plant health properties enhanced maize growth under salt stress with significant improvement in shoot and root biomass. Moreover, through the implementation of heat map and correlation analysis, this study yielded critical insights into the investigation. In summary, the integrated application of biochar and Si can be regarded as a comprehensive approach to enhance maize performance under saline conditions.