by

Samah
Ramadan
INTRODUTION
A biofertilizer is a substance which contains living
microorganisms, when applied to seed, plant surfaces,
or soil, colonizes the rhizosphere or the interior of the
plant and promotes growth by increasing the supply or
availability of primary nutrients to the host plant.

Bio-fertilizers add nutrients through the

processes of natural fixation,
nitrogen
phosphorus, solubilizing
and stimulating plant growth through the
synthesis of growth-promoting substances.
What is Bio fertilizer?
Biofertilizers are natural fertilizers that are microbial
inoculants of bacteria, algae and fungi (separately or
in combination).
which may help biological nitrogen fixation for the
benefit of plants.
They help build up the soil micro-flora and there by
the soil health.
Biofertilizer also include organic fertilizers(manure,
etc.)
Use of bio-fertilizer is recommended for improving the
soil fertility in organic farming
TYPES OF BIOFERTILIZERS

Bacterial

Fungal

Algal

Aquatic fern

Earthworms

VAM fungi
Bacteria:
Symbiotic nitrogen fixers.
Rhizobium, Azospirillum spp
Free living nitrogen fixers.
Azotobacter, Klebsiella
etc.,
Algal biofertilizers:
BGA in association with
Azolla
Anabena, Nostoc,
Ocillatoria
Fungal biofertilizer
VAM
Earthworms
Bacterial biofertilizers
The live cells of bacteria used as a biofertilizers
These microbes contains unique gene called as Nif-Gene
which make them capable of fixing nitrogen.
The nitrogen fixing bacteria work under two conditions,
Symbiotically
Free living bacteria (non-symbiotic).
The symbiotic bacteria make an association with crop plants
through forming nodules in their roots.
The free living bacteria do not form any association but live
freely and fix atmospheric nitrogen.
Symbiotic nitrogen fixers.
Most important symbiotic Nitrogen fixing bacteria is
Rhizobium and Azospirillum.
Rhizobium:
 Rhizobium lives in the root hairs of the legumes by
forming nodules
 Plant root supply essential minerals and newly synthesized
substance to the bacteria
 The name Rhizobium was established
by Frank in 1889.
 This genus has seven distinct species based
on "Cross Inoculation Group Concept".
 More than twenty cross-inoculations groups have been
established.
 A new classification has been established for
Rhizobium.
 Rhizobium can fix 50-300 kg/ha

Rhizobium
 Azospirillum:
 It mainly present in cereal plants.
inhabits both root cells as well as
surrounding of roots
forming symbiotic relation and increasing
nitrogen fixing potential of the cereal plant.
 Azospirillum is recognized as a dominant
soil microbe
nitrogen in the range of 20- 40 kg/ha in the rhizosphere in
non-leguminous plants such as cereals, millets, Oilseeds,
cotton etc.
Considerable quantity of nitrogen fertilizer up to 25-30 %
can be saved by the use of Azospirillum inoculant.
These species have been commercially exploited for the use
as nitrogen supplying Bio-Fertilizers.
Free living bacteria
Large number of free living or non -symbiotic bacteria (does
not form nodules but makes association by living in the
rhizosphere) present in soil.
Commonly used free living bacteria are
Azotobacter
Klebsiella
it will not
associated with
plant.
Azotobacter is a biofertilizer which provides the required
amount of nitrogen to the plant from the soil.
Azotobactor
Azotobactor is a heterotrophic free living nitrogen fixing
bacteria present in alkaline and neutral soils.
Azotobactor is the most commonly occurring species in
arable soils of India.
Apart from its ability to fix atmospheric nitrogen in soils, it
can also synthesize growth promoting substances such as
auxins and gibberellins and also to some extent the
vitamins.
Many strains of Azotobactor also exhibit fungicidal
properties against certain species of fungus.
Response of Azotobactor has been seen in rice, maize,
cotton, sugarcane, pearl millet, vegetable and some
plantation crops.
It improves seed germination and plant growth.
Azotobacter is heaviest breathing organism and requires
a large amount of organic carbon for its growth.
Carrier material
the use of ideal carrier material is necessary for the
production of god quality of biofertilizer
Peat soil, lignite, vermiculture, charcoal, press mud,
farmyard manure and soil mixture are used as a carrier
materials
Neutralized peat soil/lignite are found to be better carrier
materials
Ideal carrier material should be
 Cheaper in cost
 Locally available
 High organic matter content
 No toxic chemical
 Water holding capacity of more than 50%
 Easy to process
Preparation of inoculants packet
 Neutralized and sterilized carrier material is spread in a
clean, dry, sterile metallic or plastic
 Bacterial culture drawn from the fermentor is added to the
sterilized carrier and mixed well by manual or mechanical
mixer
 Inoculants are packed in a polythene bags sealed with
electric sealer
Vesicular Arbuscular Mycorrhiza
(VAM)
The term mycorrhiza was taken from
Greek language meaning
'fungus root'. term
was coined by Frank in
1885
The mycorrhiza is a mutualistic association between fungal
mycelia and plant roots.
VAM is an endotrophic (live inside) mycorrhiza formed by
aseptated phycomycetous fungi.
VAM help in nutrient transfer mainly of phosphorus, zinc
and sulfur.
Mycorrhizae is the symbiotic association between plant
roots and soil fungus of the 7 types of mycorrhizae,
VAM plays a great role in inducing plant growth.
VAM are symbiotic entophytic soil fungi, which colonize
the roots of approximately 80% plants.
The VAM hyphae also help is retaining moisture around
the root zone of plants
It increases the resistance to root borne or soil borne
pathogens and Nematodes.
 They also mobilize different nutrients like Cu(copper),
K(potassium), Al(aluminum), Mn(manganese), Fe
(iron)and Mg (magnesium) from the soil to the plant roots.
They posses vesicles (sac like structure) for storage of
nutrients and arbuscular for funneling them into root
system.
External hyphae vesicles
Morphology
Arbuscles
 External hyphae
 Arbuscles
 Vesicles
Mechanism of Action
The VAM forms an association with plant roots.
It penetrates in the root cortex and spreads around
the roots of the plant.
As the name indicates, they posses sac like structure called
vesicules which stores phosphorus as phospholipids.
The other structure called arbuscule helps bringing
the distant nutrients to the vesicules and root.
Algae as a biofertilizer
Another group of free living nitrogen fixers are cyanobacteria.
Commonly called as Blue green algae.
More than 100 species of BGA can fix nitrogen.
Nitrogen fixation takes place in specialized cells called
‘Heterocyst’
BGA very common in rice field.
Unlike Azotobacter BGA are not inhibited by the presence of
chemical fertilizers.
No chemical fertilizers added, inoculation of the algae can
result in 10-14% increase in crop yields.
They are easy to produce
Usually they are mass produced in cement tanks filled with
fresh water.
Not require any processing
Quite and cheap
Cost of 10kg may be
Rs.30-40 only
Beneficial in certain crops like vegetables, cotton,
sugarcane.
Eg. of some algal biofertilizers are
 Anabena
 Nostoc
 Oscillatoria
Advantage of biofertilizers
Renewable source of nutrients
Sustain soil health
Supplement chemical fertilizers.
Replace 25-30% chemical fertilizers
Increase the grain yields by 10-
40%.
Decompose plant residues, and stabilize C:N ratio of soil
Improve texture, structure and water holding capacity of soil
No adverse effect on plant growth and soil fertility.
Stimulates plant growth by secreting growth hormones.
Secrete fungistatic and antibiotic like substances
Solubilize and mobilize nutrients
Eco-friendly, non-pollutants and cost effective method
Disadvantages
Biofertilizers require special care for long-term storage
because they are alive.
must be used before their expiry date.
If other microorganisms contaminate the carrier medium or
if growers use the wrong strain, they are not as effective.
Biofertilizers lose their effectiveness if the soil is too hot or
dry.
THANK
YOU