Abstract:
With the continuous use of chemical fertilizers in Agriculture system may help
to produce sufficient amount of food for growing population but these
chemicals have an adverse effect both on the environment and living
organisms. Biofertilizers are a promising alternative to hazardous chemical
fertilizers and gaining importance for attaining sustainable agriculture. They
play key role in maintaining soil health and plants. Microorganisms can
interact with the crop plants and enhance their immunity, growth, and
development. Nitrogen, Phosphorous, Potassium are the essential nutrients
required for the growth of crops, but these nutrients are naturally present in
insolubilized forms. Certain microorganisms make them soluble and can be
easily assimilated by plants for their growth and development. In this study,
Azotobacter chroococcum were isolated from forest surroundings of Panbari
Dharan. 25 soil samples were collected in sterile bag and cultured in Ashby’s
media by serial dilution and incubated at 30˚C for 5 days. Morphological,
cultural, biochemical characterization was done and bacteria were identified.
Isolated A. chroococcum was cultured in Ashby’s broth and inoculated on
tomato seedlings by root dipping technique. It was found that tomato plants
inoculated with A. chroococcum has significant growth in height, no. of leaves
and root length than that of untreated tomato plants. The research result
showed that this strain had positive effect on the increase of nitrogen content
of soil. On the base of this study, it is concluded that Azotobacter
chroococcum has positive effect in growth of plants. It could be good
biofertilizer as an alternative to nitrogen fertilizer.
Description:
Dissertation
Submitted to the Department of Microbiology,
Central Campus of Technology, Tribhuvan University, Dharan, Nepal,
in Partial Fulfillment of the Requirements for the Award of Degree of
Master of Science in Microbiology
(Agriculture)
