Biofertilizer-Based Zinc Application Enhances Maize Growth, Gas Exchange Attributes, and Yield in Zinc-Deficient Soil

Zinc (Zn) concentration in soil varies from deficient to toxic. Its deficiency, as well as toxicity, through imbalanced application and cropping in industrial sites can reduce maize growth and yield. Therefore, balanced Zn application is necessary to save resources and achieve optimum growth and yield in maize. Arbuscular mycorrhizal fungi (AMF) can provide tolerance to the host plant against Zn-induced stress. Inoculation with AMF helps in regulating the uptake of Zn and enhances the growth and yield of crops. Different application rates of Zn (0, 20, 40, 60, 80, 100, and 120 mg Zn kg−1) were applied with inoculation with AMF (AM) and without AMF (NM). Results showed that root colonization was 45% higher in AMF-inoculated plants than non-inoculated plants. A significant increase in plant height (15%), number of leaves (35.4%), cob weight (4.39%), 1000-grain weight (10.5%), and biological yield (42.2%) signified the efficacious functioning of Zn20 + AM over sole inoculation with AM. We also observed that AMF inoculation with Zn20 helped to improve photosynthesis, transpiration, and stomatal conductance. Furthermore, both Zn20 + AM and Zn20 + AM significantly increased total soluble protein compared with AM. Higher application rates of zinc, i.e., Zn80 and Zn120, induced Zn toxicity with (AM) and without (NM) AMF. In conclusion, Zn20 + AM is an effective treatment to achieve better growth and maize yield without Zn deficiency or toxicity.