Enhancing Sesbania sesban L. (Merr.) growth and metal resilience by synergistic application of Trichoderma harzianum loaded biochar and biochar-zinc oxide nanocomposite

Heavy metals in agricultural soil are hazardous to the environment and human beings. So, the current study was hypothesized that Trichoderma harzianum maize biochar (MBT), and maize biochar zinc oxide nanocomposite (MB-ZnO) could effectively stabilize Cd and Cu in a polluted soil and evaluate their synergistic effects on Sesbania sesban L. (Merr.) growth. The biochar zinc oxide nanocomposite and T. harzianum loaded biochar were systematically characterized before applications. In this study, both types of engineered biochar (MB-ZnO nanocomposite and MBT) were applied to influence the growth of S. sesban. These plants were sprayed with various doses (0, 50, 75, 100 mg/L) of MB-ZnO nanocomposite and 2.0% (w/w) MBT. Foliar application of 100 mg/L MB-ZnO nanocomposite clearly reduced Cd and Cu content in the shoots of S. sesban by 30% and 31%, respectively. The combined application of MB-ZnO increased SOD (33.33%), and POD (37.5%) at the concentration of 100 mg /L. Co-applied application of MB-ZnO nanocomposite and MBT diminished Cd and Cu content by 39% and 38%, respectively, and increased soil pH (8.03 to 8.23). Conclusive findings of this study established that the application of the engineered biochar (MB-ZnO nanocomposite and MBT) is an environment-friendly and efficient way to immobilize toxic metals from the soil and improve the physiological, biochemical, anatomical, and antioxidant enzyme activities of the S. sesban plant.