Background: Magnesium deficiency has become a major nutritional disorder in lateritic soils of Kerala. Appropriate magnesium fertilization is the best strategy to combat deficiency issues. Apart from correcting nutritional deficiency, magnesium fertilization has an influence on the growth of beneficial microbes such as nitrogen fixing bacterias and arbuscular mycorrhizal fungi. The experiment aimed to investigate the effect of magnesium fertilization on crop yield and population rhizosphere micoflora of cowpea in lateritic soils of Kerala.Methods: A pot culture experiment was conducted with a gradient of magnesium additions ranging from 5 mg kg-1 to 80 mg kg-1 of soil along with recommended dose of fertilizers. Population of rhizobium, free living nitrogen fixing bacteria, spore count of arbuscular mycorrhizal fungi and per cent root colonization of arbuscular mycorrhizal fungi were studied during flowering. The available magnesium and magnesium uptake were also worked out during harvest. Yield and yield contributing characteristics of cowpea were measured during harvest stage.Result: Magnesium addition produced significant variations in population of rhizobium and free- living nitrogen fixing bacteria whereas spore count of AMF and per cent root colonization of AMF did not vary according to the added doses of magnesium. A higher population of rhizobium, free living nitrogen fixers, root nodules, magnesium uptake, plant height and yield were obtained in the treatment where magnesium was applied @ 10 mg kg-1 soil.
FREE-LIVING NITROGEN-FIXING BACTERIA PERSPECTIVE FOR CREATION OF EM-ASSOCIATIONS
