Combined application of biochar and silicon nanoparticles enhance soil and wheat productivity under drought: Insights into physiological and antioxidant defense mechanisms

Agricultural drought periods are enhanced by the change in global climate that threatens food security. One of the main factors affecting soil and wheat productivity worldwide is drought stress. Especially, in semi-arid climates, studies are not found about adding organic amendments may be a viable way to reduce the adverse impacts of drought on crops while enhancing soil qualities and water use efficiency. In this study, we aimed to explore the effects of combined application of biochar (BC = 5 %) and silicon nanoparticles (SiNP = 900 mg/L) on soil and wheat drought resistance. Drought stress was applied at the three most critical growth stages of wheat, tillering (DTS), flowering (DFS), and grain filling (DGFS) stages, then evaluated the soil nutrients and wheat drought physiological resistance under applied treatments (BC, SiNP, BC+SiNP). Results showed that combined treatment of BC and SiNP greatly reduced the adverse effects of drought by enhancing plant height (9.36 %), spike length (25.63 %), number of fertile tillers (29.26 %), grains per spike (10.86 %), thousand-grain weight (18.25 %), and biological yield (16.34 %) with comparison to the control application. Additionally, physiological measures like water use efficiency (20.58 %), stomatal conductance (29.26 %), chlorophyll a (16.25 %), chlorophyll b (18.96 %), transpiration rate (21.65 %), photosynthetic rate (22.94 %), electrolyte leakage (-17.77 %), MDA (29.25 %), hydrogen peroxide (-19.88 %), superoxide dismutase (11.19 %), catalase (9.26 %), peroxidase (18.59 %), nitrogen (14.81 %), phosphorus (13.89 %), and potassium (17.61 %) were also meaningfully improved by treated application. BC and SiNP also significantly amended the organic carbon, nitrogen, and minerals percentage in soil. In conclusion, using the synergistic application of BC and SiNP could be a successful strategy to promote the biological soil properties, plant growth, yield, and quality of wheat crops as compared to all other treatments via dropping the dangerous effects of drought stress.