Enhancing Wheat Yield and Zinc Biofortification through Synergistic Action of Potent Zinc-Solubilizing Bacteria and Zinc Sulfate in Calcareous Soil

Abstract

Zinc (Zn) is deficient all over the world, mainly in the developing countries, and zinc sulfate is applied as a source of Zn fertilizer. However, the major portions of applied zinc sulfate become unavailable to plant in the soil and can be reverted back to available by inoculating zinc-solubilizing bacteria. Given the significance of the problem, this investigation aimed to enhance wheat yield and zinc biofortification. The approach involved inoculating the crop with native zinc-solubilizing bacteria and applying zinc sulfate to calcareous soil. In this study, a pot and field experiments were conducted to evaluate the impact of treatment combinations (control (without Zn and bacterial inoculation), 4, 8, 12, 16 and 20 kg Zn ha⁻¹ were applied to soil without and with inoculation of zinc-solubilizing bacteria to seed of wheat cultivar, i.e., Wadaan-17 and Zincol-16). Results showed that zinc-solubilizing bacteria in conjunction with zinc sulfate significantly (P ≤ 0.05) increased the yield by 61%, grain zinc concentration by 139%, and apparent Zn recovery efficiency varied from 0.5 to 4.8% as compared to control under pot conditions. Similarly, under field conditions, the observations showed a 38% increase in yield, a 112% increase in grain zinc concentration and a 166% increase in zinc uptake. Additionally, the apparent zinc recovery efficiency ranged from 0.6% to 3.6% compared to the control. Among the treatment combinations, inoculation of Zn-solubilizing bacteria in conjunction with 8 kg Zn ha⁻¹ substantially boosted yield and yield attributes of wheat crop under both the pot and field conditions. Hence, it can be concluded that Zn-solubilizing bacteria have immense potential to be used as inoculants as they synergize the effect of chemical Zn, increase yield and improve the nutritional value of wheat under alkaline calcareous soil.