Microbial Population in Rhizosphere as Influenced by High Input Rates of Fertilizer Application to Sorghum on a Vertisol

Population of fungi, bacteria and actinomycetes was affected significantly with different rates of fertilizer treatments at all the crop growth stages. Fungi, bacteria and actinomycetes proliferated under NPK and FYM. Different genera of organisms were not affected by various treatments. Aspergillus, Bacillus and Actinomyces were predominant over all other groups of organisms. Increasing trend of microbial population was noticed after 30 days of sowing and it declined at harvesting stage. The bacteria and actinomycetes showed significant positive correlation with yield, uptake and available nutrient status under organic and inorganic treatments, while fungi showed positive effect under inorganic treatments and negative effect under FYM.