岡山大学環境理工学部研究報告 ISSN 2187-6940
Published by Faculty of Environmental Science and Technology, Okayama University

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Characterization and Screening of N(2)-fixing Microorganisms at Maturity Stage in Rhizosphere of Rice Grown in Brahmaputra Alluvium Soil of Bangladesh

Khan Md. H. R.
Mohiuddin M.
Rahman M.
Akhtar M. S.
Adachi, Tadashi
Abstract
Studies on the existing non-symbiotic diazotrophic systems still are the most promising for better use of biological nitrogen fixation (BNF) in agriculture. The possibilities for the extension of nitrogen fixation to rice plants still speculative. The prospect of extension of N(2)-fixation to other plants was originally formulated to simulate the possibilities for the biological use of atmospheric nitrogen in order to overcome the ecological and economical problems of nitrogenous fertilizers. In view of this, the present study was conducted for the characterization and identification of N(2)-fixing bacterial strains at the maturity (110 days) stage in rhizosphere of rice (BR 10, Oryza sativa L.) grown in Brahmaputra Alluvium soil of Bangladesh. The soil is characterized as 'Inceptisol' order and 'Aquept' suborder. It was identified as 'Dhamrai series', had 'silt' texture, pH 6.0 and 6.8 C/N ratio. The present results of the microbial tests on the rice rhizosphere soil demonstrated that out of 401 isolates, only 94 were branded as nitrogen fixing organisms per gram of soil, which is about 23.4% of the total isolates. Based on the selection criteria, four individual strains were selected for identification. Biochemical tests were conducted for proper identification. They were identified as Closteridium spp., Klebsiella spp., Bacillus spp. and Azospirllum spp.
Keywords
Azospirllum spp.
Bacillus spp.
BNF
Closteridium spp.
Diazotrophs
Klebsiella spp.
Oryza sativa L.
ISSN
1341-9099
NCID
AN10529213