INFLUENCE OF ZINC AND SILICA SOLUBILIZING MICROORGANISMS ISOLATED FROM DIFFERENT SOURCES ON CROP GROWTH AND YIELD OF DIRECT SOWN RICE (Oryza sativa L.)
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Date
2021-12-21
Authors
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ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, GUNTUR
Abstract
Rice (Oryza sativa L.) is one of the important staple food for more than 50 % of
the world’s population providing major source of the food energy. Rice plays a crucial
role in Indian agriculture contributing to 20-25 % of agricultural income. It contributes
about 43% of the total food grain production and about 46 % of the total cereal
production in India. Depending on water and labour paucity, farmers are altering rice
establishment methods from transplanting to direct seeding in unpuddled soil as it is
possible to save water and labour wages etc. In direct sown rice, zinc and silica
deficiencies were observed in most of the rice growing areas of India posing a threat to
the crop plant growth and yield.
Keeping in view of future requirements and present needs this study was framed
to develop bacterial inoculants for zinc and silica solubilisation in direct sown rice. A
total of thirty two zinc solubilising bacterial inoculants and twenty eight silica
solubilising bacterial inoculants were isolated from Kurnool district (Mandals of
Atmakur, Kothapalle, Jupadu bungalow, Pamulapadu and Velugodu), Prakasam district
(Mandals of Tripuranthakam, Yerragondapalem, Dornala, Markapuram and Giddalur),
Guntur district (Mandals of Vinukonda, Narasaraopet, Chilakaluripet, Sattenapalle and
Piduguralla) and Anantapur district (Mandals of Guntakal, Gooty, Pamidi, Tadipatri and
Uravakonda).
After through screening for different plant growth promoting characteristics i.e.,
zinc solubilization efficiency, silica solubilization efficiency, phosphate solubilization
efficiency, potassium releasing efficiency, exopolysaccharide production activity, indole
acetic acid production activity, siderophore production activity and different
biochemical tests, two efficient zinc solubilizing bacterial isolates and two efficient
silica solubilizing bacterial isolates were selected. The efficient isolates were identified
as ZnKJJ-4 (Pseudomonas knackmussii B13 - 99.80 % identity), ZnPGG-1
(Pseudomonas aeruginosa strain FQM - 99.66 %), SiKPP-1(Bacillus mucilaginosus
strain CGMCC 1.2326 - 99.95 % identity), SiPYY-3 (Bacillus megaterium PSB1 -
99.92 % identity) by using 16S rRNA phylogenetic study.
Further, shelf life of efficient zinc and silica solubilizing bacterial isolates were
studied using different carrier material (Lignite, peat and charcoal powder) to check the
viability in a period of six months of storage in the incubator at 250C. Zinc solubilizing
bacterial isolates survived better in the lignite. Silica solubilizing bacterial isolates
persisted in charcoal powder.
Pot culture and field trials were conducted with efficient zinc and silica
solubilizing bacterial isolates and their consortia (ZnKJJ-4 + ZnPGG-1 + SiKPP-1 +
SiPYY-3) in combination with different treatments and recommended dose of fertilizer.
In the pot culture experiment, significantly highest zinc solubilizing bacteria (6.94 Log
CFU g-1 soil), silica solubilizing bacteria (6.98 Log CFU g-1 soil), total bacteria (9.85
Log CFU g-1soil), fungal population (5.37 Log CFU g-1 soil) and actinomycetes
population (6.68 Log CFU g-1 soil) were observed in T13 (RDF + ZnKJJ-4 & ZnPGG- 1
+ SiKPP-1 & SiPYY-3) at 90 DAS. Highest chlorophyll content (1.94 mg g-1), dry
matter production (47.7 gm pot-1),available nitrogen (249.4 kg ha-1), available
phosphorus (61.8 kg ha-1), available potassium (347.9 kg ha-1), zinc (0.99 ppm) and
silica content (90.8 ppm) in soil was highest in T13 in pot culture experiment. Highest
dehydrogenase activity (574.7 μg TPF g-1 day-1), acid phosphatase activity (85.36 μg
pNP g-1 h-1), alkaline phosphatase activity (138.69 μg pNP g-1 h-1) and urease activity
(69.61 μg TPF g-1 day-1) in soil was observed in T13.
Highest nitrogen (0.99 %), phosphorous (0.58 %) and potassium (2.18 %)
percentage in plant was found in T13 at 90 DAS in pot culture. Similarly, zinc (0.75
ppm) and silica (0.99 ppm) content in plant and also total zinc (0.39 ppm) and silica
(0.89 ppm) content in grain were highest in T13 in pot culture experiment at 90 DAS.
Plant height at 90 DAS (75 cm), panicle length (17.4 cm panicle-1), number of grains
per panicle (145 panicle-1), number of filled grains per panicle (127 panicle-1), 1000
grain weight (17.1 g), grain yield (27.9 g pot-1) and straw yield (49.7 g pot-1) were
significantly higher in T13 when compared to the other treatments in pot culture.
In the field studies, T13 (RDF + ZnKJJ-4 & ZnPGG- 1 + SiKPP-1 & SiPYY-3)
at 90 DAS recorded significantly highest zinc solubilizing bacteria (6.98 Log CFU g-1
soil), silica solubilizing bacteria (6.94 Log CFU g-1 soil), total bacteria (9.96 Log CFU
g-1 soil), fungal population (5.48 Log CFU g-1 soil) and actinomycetes population (6.89
Log CFU g-1 soil). Highest chlorophyll content (2.04 mg g-1), dry matter production
(2547kg ha-1), available nitrogen (262.3 kg ha-1), available phosphorus (64.7 kg ha-1),
available potassium (349.6 kg ha-1), zinc (1.14 ppm) and silica (98.9 ppm) content in
soil were found highest in T13. Highest dehydrogenase activity (583.6 μg TPF g-1 day-
1), acid phosphatase activity (90.18 μg pNP g-1 h-1), alkaline phosphatase activity
(148.69 μg pNP g-1 h-1) and urease activity (72.72 μg TPF g-1 day-1) in soil was
observed in T13.
Highest nitrogen (1.10 %), phosphorous (0.67 %) and potassium (2.29 %)
percentage as well as zinc (0.96 ppm) and silica (1.08 ppm) content in plant were found
in T13 at 90 DAS in field conditions. Under field conditions, T13 recorded highest total
zinc (0.58 ppm) and silica (0.98 ppm) content in grain. Plant height at 90 DAS (77.1
cm), total number of tillers per m2 (496), panicle length (18.2 cm panicle-1), number of
grains per panicle (157 panicle-1), number of filled grains per panicle (140 panicle-1),
1000 grain weight (19.2g), grain yield (5523 kg ha-1) and straw yield (6893 kg ha-1)
were significantly higher in T13 when compared to the other treatments.
The present investigation showed influence of efficient zinc and silica
solubilizing microorganisms on the plant growth and yield of direct sown paddy crop
under pot culture and field conditions. Zinc and silica solubilising bacteria along with
RDF (T13) enhanced the availability N, P, K, Zn and Si nutrients in the soil and nutrient
content in plant, improved the enzymatic activity, soil microflora, soil health and
fertility status of the soil.
Description
INFLUENCE OF ZINC AND SILICA SOLUBILIZING MICROORGANISMS ISOLATED FROM DIFFERENT SOURCES ON CROP GROWTH AND YIELD OF DIRECT SOWN RICE (Oryza sativa L.)