INTEGRATING THE POTENTIAL OF BACILLUS SP. AZ6 AND ORGANIC WASTE FOR ZINC OXIDE BIO-ACTIVATION TO IMPROVE GROWTH, YIELD AND ZINC CONTENT OF MAIZE GRAINS

Abstract

Cereal crops are a major part of our daily dietary intake. However, they are reported to have poor zinc (Zn) content. Bio-activation of zinc oxide with zinc solubilizing bacteria (ZSB) is considered a relatively newer approach to enrich cereal grains with Zn. The present study was conducted to evaluate the role of four bio-activated ZnO (BOZ) formulations in improving the growth, yield and grain Zn concentration in maize. The BOZ formulations were prepared by mixing ZnO and ground orange peels inoculated with ZSB, Bacillus sp.AZ6. Four different BOZ formulations [BOZ-1 (9:1), BOZ-2 (8:2), BOZ-3 (7:3) and BOZ-4 (6:4)] were prepared by mixing ZnO in different ratios with inoculated ground orange peel. In a soil incubation study (72 days), the bioavailable Zn fraction was found to be higher in the soil treated with BOZ-4 formulation as compared to the soils treated with other formulations as well as zinc sulfate (ZnSO4) and zinc oxide. The results of the pot study revealed the supremacy of BOZ-4 over other treatments in improving growth, yield and quality of maize. The BOZ-4 formulation resulted into 14, 20, 05, 11 and 27% increase in plant height, root length, 100-grain weight, grain yield and Zn concentration in grain, respectively, as compared to zinc sulfatetreatment. Results suggested that bio-activation of ZnO by Bacillus sp. AZ6 and orange peels waste is an effective strategy to improve yield and nutritional quality of maize.