Combined use of zinc nanoparticles and co-composted biochar enhanced wheat growth and decreased Cd concentration in grains under Cd and drought stress: A field study

Toxic metals present in soil and water severally affect the food crops and create serious health concerns. The current field study was focused on the impacts of foliar spray of zinc oxide nanoparticles (ZnO NPs) (100 mg/L) and soil applied co-composted biochar (0.5% w/w) on yield and cadmium (Cd) accumulation by grains of wheat (Triticum aestivum L.) under simultaneous Cd and water limited stress. After 60 days of seeds sowing, drought stress was initiated in half plots by alternate irrigation compared to normal irrigation. Plants were harvested after 122 days and various physiological parameters were measured. Results showed that drought and Cd stress collectively decreased plant dry weight and chlorophyll contents and caused oxidative stress in leaves. While application of NPs and co-composted biochar improved the plants biomass and chlorophyll contents by overcoming the oxidative stress and alterating the antioxidants enzymatic activities in stressed plants. Combined application of NPs and co-composted biochar restricted the Cd uptake below its threshold level in grains (0.2 mg/kg). The current study concluded that the combination of ZnO NPs and co-composted BC was helpful to improve wheat growth and biomass, chlorophylls contents, antioxidant enzyme activities by scavenging ROS and reducing Cd uptake by plants under simultaneous Cd and drought stress.