Enzymatic alterations of soil and plant system on applied Zn sources, organics and microbial inoculants in zinc deficient calcareous and non-calcareous soils

The study aimed to investigate the impact of zinc (Zn) nutrition on enzymatic activity in soil and plant systems of zinc-deficient soils. Additionally, it aimed to understand the impact of solubilizer (such as Zinc Solubilizing Bacteria) and mobilizer (like AM Fungi) on enzyme activity and zinc nutrition in plants across calcareous and non-calcareous soil environments. A pot experiment was carried out with two different soils with three Zn sources (ZnSO₄, ZnO and Zn-EDTA), organic manure (FYM) and microbial inoculants - Zinc Solubilizing Bacteria (ZSB) and Arbuscular Mycorrhizal Fungi (AM F). The DTPA-Zn and plant Zn content increased with applied sources of Zn. The microbial inoculants and FYM enhanced the use efficiency of all sources of Zn compared to unapplied treatments. Regarding soil enzyme activity, FYM and AM fungi played a major role which in turn altered the dehydrogenase (SDHA) and alkaline phosphatase (AlP) activities in both soils. The Zn sources and ZSB addition enhanced the plant enzyme activity. Calcareous soil recorded higher CA, SOD and alkaline phosphatase activities compared to non-calcareous soil the latter registered higher dehydrogenase activity and fruit Zn content.