Effect of Zn fertilizer in combinations with arbuscular mycorrhizal fungi and zinc solubilising bacteria on micronutrients transformations and uptake in maize grown on calcareous soils

Abstract

A field experiment was conducted in black soils in order to study the micronutrients viz., iron (Fe), Manganese (Mn) and copper (Cu) transformation in soil under maize cultivation and their uptake of by maize using Arbuscular Mycorrhizal (AM) fungi and Zinc Solubilizing Bacteria (ZSB) in combination with graded levels of ZnSO4. Treatment consisted of two factors viz., microbial inoculation (M1: control, M2: AM fungi, M3: ZSB and M4: M2+M3) 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 @ 45 and 65 days after sowing) replicated three times in randomized block design (RBD). The results revealed that the microbial inoculation significantly increased the soil available micronutrients Fe, Mn and Cu content at vegetative, flowering and harvesting stages of maize crop. Among the graded doses of Zn, the highest available micronutrients content was recorded with the treatment S5 followed by S4, S3 and S2 over the control. The application of M4S5 resulted in higher DTPA extractable micronutrients Fe, Mn, and Cu compared to the other treatment combinations. Application of AM fungi + ZSB (M4) registered the highest uptake of micronutrients by grain. Graded levels of Zn application enhanced the nutrient uptake correspondingly. However, beyond 25 kg of ZnSO4 ha-1, the increase in Fe, Mn and Cu was not statistically significant.