Abstract

                                A Field experiment was conducted during 2014 at Cotton Research Station Farm, Perambalur district in black soil in order to study the soil available NPK and their uptake using Glomus intraradices (AM fungus) and zinc solubilizing Bacillus sp. (ZSB) in combination with graded levels of ZnSO4 in maize (Zea mays L.). Treatments consisted of two factors viz., microbial inoculation (M1 control, M2 AM, M3 ZSB and M4 AM + ZSB) and graded levels of ZnSO4(S1 0,S2 12.5, S3 25, S4 37.5, S5 50 kg ha -1 and S6@ 0.5% foliar spray on 45 and 65 DAS) replicated thrice in FRBD. The soil available N decreased with the advancement of crop growth in black soil. The combination of AM and ZSB had enhanced the soil available NPK and uptake at vegetative, tasselling and harvest stages of crop growth. Increased doses of ZnSO4 application had positive effect on the soil available N and K at all stages. Graded doses of ZnSO4 on soil available P was not spectacular. Although it enhanced the NPK uptake correspondingly, the increase was not significant beyond 25 kg of ZnSO4 ha-1. Combined application of AM and ZSB along with 50 kg of ZnSO4 ha-1 had recorded the highest soil available NPK and their uptake at vegetative, tasselling and harvesting stages. The application of graded doses of ZnSO4 in combination with AM and ZSB had also increased the soil available NPK, which in turn increased the fertility status of soil resulting in increased uptake of all the three primary nutrients.

Key words : Maize, Glomus intraradices (AM), Zinc solubilizing Bacillus sp., ZnSO4, NPK availability and uptake