Agriculture Reference
In-Depth Information
that incorporation of
Azolla-Anabaena
to paddy field increases rice yields and ad-
dition of dried
Azolla filiculoides
at the rate of 93 kg N/ha has increased a rice yield
upto 70 %, the increase obtained with an equivalent amount of ammonium sulphate
(Anitha and Kannaiyan
1999
). In a field experiment the cyanobacteria was used
to degrade coir pith with the help of lignolytic enzyme. (Malliga et al.
1996
) and
produced cyanopith, it can be used as bio-fertilizer to improve the crop productivity
(Jha and Prasad
2005
). Coir pith contains high lignin (31 %), cellulose (27 %), con-
tent (Bhat et al.
2003
) and carbon nitrogen ratio (C/N) of 104:1 (Palaniappan
2005
).
Manoharan et al.
2011
used cynopith as bio-fertilizers on
Amaranthus dubius
that
increases the growth of
Amaranthus
.
Azospirillum
Azospirillum
is microaerophilic
,
free living, non-symbiotic, loosely associative
nitrogen fixing bacteria and it establishes a close association with various plants
mainly with C
4
maize, sorghum, sugarcane, ray grass,
Amaranthus
etc. This micro-
organism fixes atmospheric N and makes it available for plants in asymbiotic man-
ner (Steenhoudt and Vanderleyden
2006
)
. Azospirillum
grows in the rhizosphere of
the plants or occasionally penetrates into the root tissues but is not able to produce
any visible nodule or out growth on the root tissue but grows intracellularly (Saikia
et al.
2007
). This association is due to the ability of the microbe to use malic acid,
an organic acid formed for capturing CO
2
as a carbon source. It also secretes vari-
ous phytohormones which include gibberellins, cytokinins, auxins and affect de-
velopment and morphology of root by increasing root length, number of root hair
cells, lateral roots. Azosprillium also secretes iron-chelating siderphores that help
in the sequestering of iron sufficient for plant growth (Romerheld and Marshner
1986
). A free living nitrogen fixing bacteria was for the first time reported by Bei-
jerinck in 1925 under the name of
Spirillum lipoferum
and later on renamed this
organism as
Azospirillum
(nitrogen fixing Spirillum) in 1978.
Azosprillium
is one
of recognized dominant soil microbe and is able to fix about 10-40 kgN/ha.
The
Azosprillium
inoculation improves vegetative growth of the plants (Naderifar and
Daneshian
2012
). Till date only four species of
Azospirillum
have been identified
which include
A. lipoferum, A. brasilense, A. amazonense, A. iraquense
. Among
these species only
A. brasilense and A. lipoferum
are very common in Indian soils.
Inoculation of vegetable crops with
Azospirillum
has resulted in yield enhancement.
The field experiment of
Azosprillium
with maize was examined and was confirmed
that this association benefits enzyme activating glutamine synthetase and glutamine
synthetase in the leaves of paranodulated maize plants. Bhaskara Rao and Charyulu
(
2005
) studied the association of
A. lipoferum
inoculated to foxtail millet plant in
combination with N fertilizer and demonstrated the increase in plant growth level,
dry weight of shoot and root over when compared with control plants.
Maize plants inoculated with
Azospirillum
showed high rate of photosynthesis
and stomatal conduction leading to high yield compared to control plants (Kumar
Search WWH ::
Custom Search