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