Conjoint application of Ni and Mn on the enzymatic activities, nutritional parameters, and nutrient concentration in the soybean crop grown in the Ni and Mn-deficient soil

The conjoint application of manganese (Mn) and nickel (Ni) at various doses and its comprehensive investigation at the nutrient concentration and biochemical levels have not been studied in soybean crop in detail so far. To, solve this purpose a pot experiment was conducted in glass house on low nickel and manganese soil in Department of Soil Science and Agricultural Chemistry,Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, during 2019–20 and 2021–22. There were 10 treatments with two levels of Ni (5 and 10 mg kg −1) and Mn (10 and 20 mg kg−1) with recommended dosage of fertilizers nitrogen, phosphorus, potassium(8.93, 35.71 and 17.86 mg kg−1) applied to all treatments except control. The result of the study showed that the maximum concentration of iron (Fe) at 30 DAS (Days after sowing), 60 DAS, 90 DAS in root and leaves of soybean was recorded in T3(RDF + Ni10) which was 698 and 317 mg kg−1, while in stem maximum concentration reported in T4(RDF + Mn10). While in case of Mn, Ni, N, Mg, Cu and Zn maximum concentration at 30 DAS, 60 DAS, 90 DAS in root, leaves and stem were reported in T9(RDF + Ni10Mn20). The minimum concentration of Fe, Cu, Mn, Zn, Ni, N and Mg at 30 DAS, 60 DAS,90 DAS in root, leaves and stem were reported in T1(RDF).The maximum enzymatic activity (Catalase, Ascorbate peroxidase, Lipid peroxidase and Superoxide Dismutase) reported in T9(RDF + Ni10Mn20), while lowest reported in T1(RDF). Further protein and oil seed content in soybean crop recorded to be highest in T9(RDF + Ni10Mn20), while lowest reported in T1(RDF). Overall, the study highlights the synergistic interaction between Ni and Mn in enhancing nutrient uptake, enzymatic activity, and seed quality in soybean, thereby providing critical insights for optimizing micronutrient management in soybean production systems.