MSc 1997

The study on Azotobacter and Azospirillum inoculants for nitrogen
economy in vegetable cultivation was conducted at College of Agriculture,
Vellayani, Thiruvananthapuram during 1994-1996. Two sets of
experiments consisting of pot and field trials were conducted for this
purpose.
Pot culture experiments with amaranthus showed that, plant height,
root biomass, leaf area index and yield were significantly high in the
treatment combination of Azospirillum inoculation along with FYM and 75
percent fertilizer nitrogen (N3FYM+AS). Flowering time was also
significantly delayed in this treatment.
Among Azotobacter treatments also plant height, leaf area index and
yield were significantly high in the treatment receiving 75 percent nitrogen
along with FYM and Azotobacter inoculation (N3FYM+AB).
In brinjal while Azospirillum inoculation along with 75 percent
nitrogen and FYM (N3FYM+AS) could significantly increase yield and

increase plant height and root biomass production, there were no
significant difference among Azotobacter treatments on yield.
In chilli also Azospirillum treatment coupled with vermicompost and
100 percent nitrogen (N4 VEC+AS) was significantly increasing number of
branches, number of fruits and yield. Whereas there were no significant
differences among Azotobacter treatments on yield of chilli.
When the individual effect of organic manure and biofertilizer
application for all the three crops were studied, no significant differences
were obtained between two biofertilizer treatments except for some delay
in flowering time in amaranthus due to Azospirillum inoculation. But
FYM application had favorable effects in most of the plant growth and
yield parameters of all the three crops.
The selected treatments from pot culture experiments were
evaluated under field conditions for all the three crops.
Maximum yield for amaranthus was obtained in Azotobacter
treatment with FYM and 75 percent fertilizer nitrogen (N3FYM+AB),
which also had a significant increase in plant height.

For brinjal, the Azotobacter treatment recervmg FYM and 75
percent nitrogen (N3FYM+AB) produced maximum plant height, number
of branches, number of fruits and yield. But keeping quality of fruits was
significantly high in Azotobacter treatment with full dose of vennicompost
and 75 percent fertilizer nitrogen (N3 VECF+AB).
For chilli, Azospirillum treatment receiving full dose of
vermicompost and 100 percent nitrogen (N4VECF+AS) produced
maximum yield which also has got maximum plant height. Keeping
quality of fruits was also significantly high in this treatment.
The population of bacteria, fungi, actinomycetes, Azospirillum and
Azotobacter were significantly high in most of the treatments receiving
either Azospirillum or Azotobacter inoculants and organic manure
supplements.