Agriculture Reference
In-Depth Information
chemical fertilizers on soybean yield, carried out an experiment at the University of
Tabriz Research Farm, Iran. Biological fertilizer consisting of (1) non-inoculated
(NI), (2) PS bacteria (PSB), (3)
Bradyrhizobium japonicum
(BJ), and
(4)
B. japonicum
+ PSB (BJ + PSB) was in the presence of absence of varying levels
of chemical fertilizers: (1) control (0 %), (2) 16.5 kg/ha
1
urea + 49.5 kg/ha
1
triple
superphosphate (33 %), (3) 33.3 kg/ha
1
urea + 99 kg/ha
1
triple superphosphate
(66 %), and (4) 50 kg/ha
1
urea + 150 kg/ha
1
triple superphosphate (100 %). Grain
weight was significantly enhanced following BJ and BJ + PSB application over NI
and PSB. Also, grains per pod were more in bio-inoculated plants. Plant biomass,
grains per plant, and grain yield per plant in NI- and PSB-inoculated plants were
enhanced with increasing chemical fertilizers. The highest plant biomass, grains per
plant, and grain yield were recorded for treatment having 16.5 kg/ha
1
urea
+ 49.5 kg/ha
1
BJ + PSB. Inoculation of seeds
by BJ and BJ + PSB without chemical fertilizer application had equal or higher
performance than non-inoculated seeds with 100 % chemical fertilizer. Therefore,
soybean seed inoculation by
B. japonicum
singly or in combination with PSB not
only reduced the use of chemical fertilizer but also highlighted the role of syner-
gistic microbes in improving the yield and yield components of soybean. In a
follow-up study, Suri and Choudhary (
2013
) determined the interactive effects of
soybean-AM fungi (
Glomus mosseae
and
G. intraradices
)-PS bacterium (
P. striata
)
on the productivity, nutrient dynamics, and root colonization in soybean grown in
P-deficient Himalayan acidic alfisol. Sole application of PSB or AM fungus con-
siderably enhanced VA-mycorrhizal root colonization and root weight besides crop
productivity and nutrient uptake over control. The co-inoculation of PSB and AM
fungus also showed a similar stimulatory effect on mycorrhizal root colonization
and root weight relative to control. Dual inoculation of
G. mosseae
and
P. striata
significantly increased the grain and straw yield besides grain protein content
suggesting a strong synergism between the AM fungus and PS bacterium. The
impact of co-culture of either
G. intraradices
or
G. Mosseae
with PSB in the
presence of 75 % P
2
O
5
on crop productivity, nutrient content, nutrient uptake,
and soil fertility was at par with sole application of 100 % P
2
O
5
, but the root
colonization and root weight were maximum at flowering stage indicating that
Glycine
-
Glomus
-PSB interactions in combination with 75 % P
2
O
5
dose based on
STCR precision model could lead to the reduction in fertilizer application by about
one-fourth without disturbing the soybean productivity and soil fertility in a
Himalayan acidic alfisol region.
Gui˜az´ et al. (
2010
) in a similar study evaluated the effect of single or mixed
cultures of nodule bacterium (
S. meliloti
B399) and PS bacterium (
Bacillus
sp. and
Pseudomonas
sp.) on N-fixing efficiency of alfalfa plants and observed that the sole
culture of
Pseudomonas
sp. FM7d significantly enhanced the dry matter accumu-
lation in roots and shoots, length of plants and surface area of roots, and symbiotic
attributes of alfalfa plants. On the contrary, the mixture of
S. meliloti
B399 and
Bacillus
sp. M7c further increased the measured parameters suggesting a synergis-
tic/additive effect of the two phenotypically different bacterial genera. Likewise,
the tripartite combination of
Rhizobium
, PGPR, and PSB has been found to signif-
icantly increase nodulation and grain yield relative to uninoculated mung bean
triple superphosphate fertilizer
