Vol. 9, Issue 2, Part G (2024)

Author(s): Meenakshi BC

Abstract: An experiment was conducted to assess the microbial communities present in the rhizosphere soil of aerobic rice at different depths under glass house condition. The 3 feet length 4 inches diameter PVC pipes filled with soil were placed in battery boxes and seeds of aerobic rice varieties BI-33 (renamed as ARB-6) and AM-72 were sown and watered as and when required. After germination, three plants were maintained in each pipe with three replications. Soil samples were collected on 40^th and 80^th day of sowing by cutting the rhizosphere soil profile at 5 cm, 10 cm, 20 cm, 40 cm, 60 cm, 80 cm and 100 cm depth. Soil was thoroughly mixed and random soil sample was collected at each mentioned depth. The microbial population of rhizosphere present at different depths was enumerated by serial dilution plate method using suitable agar media. The highest population of bacteria including free living nitrogen fixers, phosphate solubilizers and fungi were present at 5 to 10 cm depths and the populations of the communities decreased as the depth of soil increased. Contrary to this, the population of actinomycetes increased as the depth of soil increased. This concludes that microbial population varies significantly with different soil depths and further, several factors could greatly influence the microbial communities that improve crop production.