Studies on Microbial Changes in Soil as a Result of Continuous Application of Fertilizers, Farmyard Manure and Lime

Effect of continuous application of fertilizers, FYM and lime on microbial population of an acidic red loam soil was studied. While bacteria, actinomycetes, Azotobacter, cellulose decomposers and phosphate solubilizers increased in FYM, FYM+lime+PK and lime+NPK, fungl and Beijerinckia proliferated under N, NP and NPK treatments. Azotobacter was absent in the latter three due to unfavourable pH condition created. Microbial population in the wheat rhizosphere was invariably higher than that in the non-rhizosphere but FYM application alone or in combination with the inorganics and lime supported greater population of bacteria and actinomycetes. Ammonium sulphate incorporation stimulated fungal population both in the rhizosphere and non-rhizosphere. A significant positive correlation between the rhizosphere microflora and CO₂ evolution was observed.