African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6801

Full Length Research Paper

Studies on heterotrophic bacteria with special reference to Azospirillum from rhizosphere and root of different crops

Tripathi J.1, Singh A. K.2 and Tiwari P.3
1Sai Baba Adarsh Mahavidyalaya, Ambikapur, Chhattisgarh, India. 2RMD College of Agriculture and Research Station, Ajirma, Ambikapur, Chhattisgarh, India. 3Government College Bhanupratappur, Kanker, Bastar, Chhattisgarh, India.  
Email: [email protected], [email protected]

  •  Accepted: 09 July 2013
  •  Published: 11 July 2013


Availability of heterotrophic soil bacteria and an associative micro-aerophilic nitrogen fixing Azospirillum, from the rhizosphere of different crop plants, was studied. Microorganisms were reported from root and rhizospheric soil (from twenty-seven different samples collected from Chhattisgarh, India) of different crop plants. The amount of total heterotrophic bacteria, in different samples, varied significantly from 3.01×108 to 4.90×108 in rhizosphere and from 1.11×108 to 2.91×108 in root tissues. Azospirillum population significantly varied from 3.81×108 to 4.90×108 in rhizosphere and from 2.09×108 to 2.88×108 in root tissues. Rhizospheric soils were found to harbor the highest population of heterotrophic soil bacteria and Azospirillum in comparison with plant tissues. Nitrogen, phosphorus, potash, organic matter (OM) and pH value have significant positive correlation but electrical conductivity (EC) have non-significant effect with total heterotrophic bacterial population. Based on the correlation co-efficient (r) value, all significant positive correlation has been grouped in three categories viz; strong (r = >0.5), medium (r = >0.4 but <0.5) and weak (r = <0.4). Thus, in the present study, N, OM and rhizospheric pH have strong significant positive correlation with total heterotrophic bacterial population while P and K content have medium correlation with bacterial population.


Key words: Heterotrophic bacteria, rhizosphere, Azospirillum, nitrogen fixing bacteria, correlation, regression.