INTRODUCTION
Many heterotrophic bacteria and fungi and fungi
efficiently solubilize insoluble phosphate of rock efficiently solubilize insoluble phosphate of rock
phosphate groups when added to the soil. These phosphate groups when added to the soil. These
organisms secrete organic acids and enzymes that organisms secrete organic acids and enzymes that
solubilize insoluble phosphorus which becomes then solubilize insoluble phosphorus which becomes then
available for plant absorption.available for plant absorption.
Phosphate Solubilizing Biofertilizers as component of INM
Many bacteria belonging to Bacillus, Pseudomonas Flavobacterium Micrococcus Streptomyces and fungi belonging to Aspergillus Penicillium and Trichoderma efficiently solubilize insoluble phosphate of rock phosphate groups. These organisms secrete organic acids and enzymes that Solubilize insoluble phosphorus added to the soil, which becomes then available for plant absorption
Phosphate Solubilizing Bacteria
Spore Rod shape
Rod shape FlagellaPigmentation
Colony
BACILLUS
PSEUDOMONAS
Phosphate Solubilizing Fungi
Aspergillus awamori
Aspergillus conidia Aspergillus colony
Aspergillus fruiting body
Penicillium Trichoderma viridi
Mechanism of Phosphorus solubilization
Organisms are Pseudomonas, Bacillus, Aspergillus Penicillium, Trichoderma Bacteria and fungi secrete organic acids and EnzymesOrganic acids and Enzymes dissolve insoluble phosphorus bound with soil and organic matter
Selection Procedure
Bacteria / fungi in specified media containing insoluble phosphate
Incubate and observe the clearing zone around colonies
Quantify the phosphorus dissolved by specified organism Select efficient culture based on above criteria
CLEAR ZONE AROUND BACTERIAL COLONIES
INDICATE DISSOLUTION OF INSOLUBLE
PHOSPHATE
Treatment
Wheat Rice Chickpea Grain yield Grain yield Grain yield
Control P. striata B. polymyxaA. awamoriRock phosphateRP+ P. striataRP+ B. polymyxaRP+ A. awamoriSuper phosphate
344037303660362037304350417041704440
249025402580256027202740282027402870
237024602920278025602920314030702850
Phosphate Biofertilizer enhance yield of Wheat Rice and Chickpea
PSB increase crop yield by 5-10 %
LET US SUM UP
Many heterotropjic bacteria and fungi efficiently efficiently
solubilize insoluble phosphate of rock phosphate solubilize insoluble phosphate of rock phosphate
groups. groups.
These organisms solubilize phosphate by secreting These organisms solubilize phosphate by secreting
organic acids and enzymes that render solubilization organic acids and enzymes that render solubilization
of insoluble phosphorus added to the soil, which then of insoluble phosphorus added to the soil, which then
becomes available for plant absorption.becomes available for plant absorption.
contd…contd…
contd…
Inoculation of phosphate solubilizing micro
organisms increase crop yield by 5-10 %.
The integrated use of rock phosphate and PSM add
30-35 kg P2O5/ha.
ASSESSMENTWrite true or false :
i) The bacteria genera Bacillus, Pseudomonas,
Flavobacterium,Flavobacterium, Micrococcus Micrococcus and and StreptomycesStreptomyces can
solubilize insoluble phosphate.
ii) The clear zone around bacterial colonies indicate
dissolution of insoluble phosphate.
iii) Inoculation of phosphate solubilizing microorganisms
increase crop yield by 20 %.
iv) iv) Mechanism of phosphorus solubilization involves Mechanism of phosphorus solubilization involves
secretion of organic acids and enzymes.secretion of organic acids and enzymes.
INTRODUCTIONASSESSMENTModel answers :
i) True
ii) True
iii) False
iv) True
REFERENCES
i) Soil Microbiology – N. S.Subba Rao
ii) Advances in Microbiology – N. S.Subba Rao
iii) Bio-fertilizer and Organic Farming – NIIR Board
iv) Nitrogen fixing organisms
(Pure and applied aspects) – J. I. Sprent and
P. Sprent