Dr. J.S.

Bamboriya

BIOFERTILIZERS

Biofertilizers are defined as preparations containing living or latent cells of microbes

which helps in enhancing the soil fertility either by fixing atmospheric nitrogen, solubilization
of phosphorus or decomposing organic wastes or by augmenting plant growth by producing
growth hormones with their biological activities.
Use of biofertilizers is one of the important components of integrated nutrient
management, as they are cost effective and renewable source of plant nutrients to
supplement the chemical fertilizers for sustainable agriculture. Several microorganisms and
their association with crop plants are being exploited in the production of biofertilizers. They
can be grouped in different ways based on their nature and function.
I. N2 FIXERS

a. Free living : Aerobic – Azotobacter, Beijerinckia, Anabaena

Anaerobic – Clostridium
Facultative anaerobic – Klebsiella

b. Symbiotic : Rhizobium, Frankia, Anabaena azollae

c. Associative symbiotic : Azospirillum

d. Endophytic : Gluconacetobacter
Burkholdria
II. PHOSPHORUS SOLUBILIZERS

Bacteria : Bacillus megaterium var. phosphaticum

B. subtilis, B. circulans
Pseudomonas striata

Fungi : Penicillium sp.

Aspergillus awamori

III. PHOSPHORUS MOBILIZERS

a) AM fungi : Glomus sp., Gigaspora sp., Acaulospora sp.
b) Ectomycorrhizal fungi : Amanita sp., Boletus sp., Laccaria sp., Pisolithus sp.
c) Ericoid Mycorrhiza : Pezizella ericae
d) Orchid mycorrhiza : Rhizoctonia solani

IV. POTASH SOLUBILIZERS : Bacillus mucilaginosus, Fraturia aurantia

V. SILICATE AND ZINC SOLUBILIZERS: Bacillus sp
VI. PLANT GROWTH PROMOTING RHIZOBACTERIA: Pseudomans spp., and many more
Dr. J.S. Bamboriya

IMPORTANCE OF BIOFERTILIZERS
Biofertilizers are known to make a number of positive contributions in agriculture.
 Supplement fertilizer supplies for meeting the nutrient needs of crops.
 Replace 25-30% chemical fertilizers.
 Add 20 – 200 kg N/ha (by fixation) under optimum conditions and solubilize/mobilize
30-50 kg P2O5/ha.
 They liberate growth promoting substances and vitamins and help to maintain soil
fertility.
 They suppress the incidence of pathogens and control diseases.
 Increase the crop yield by 10-40%. N2 fixers reduce depletion of soil nutrients and
provide sustainability to the farming system.
 They improve soil physical properties, tilth and soil health.
 Biofetilizers are eco-friendly, non-pollutants and cost effective.

DISADVANTAGES OF BIOFERTILIZERS
 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.

1. STRUCTURE AND CHARACTERISTIC FEATURES OF RHIZOBIUM

Description and characteristics
Classification

1. Family : Rhizobiaceae
2. Genus : Azorhizobium- for stem nodulation (Sesbania rostrata)

Bradyrhizobium- Slow growing (Soybean, Lupin & Cowpea miscellany)

Rhizobium – Fast growing (Pea, Lentil, Bean, Lathyrus, Berseem)

Morphology
1. Unicellular, cell size less than 2µ wide, short to medium rod, pleomorphic.
2. Motile with Peritrichous flagella
3. Gram negative
4. Accumulate PHB granules.
Physiology
1. Nature : Chemoheterotrophic, symbiotic with legume
2. C source : Supplied by legume through photosynthates,
monosaccharides, disaccharide
3. N source : Fixed atmospheric N2

4. Respiration : Aerobic
5. Growth : Fast (Rhizobium), slow (Bradyrhizobium)
Dr. J.S. Bamboriya

6. Doubling time : Fast growers – 2-4 hrs

Slow growers – 6-12 hrs
7. Growth media : YEMA

Rhizobia are soil bacteria, live freely in soil and in the root region of both leguminous
and non-leguminous plants. However they enter into symbiosis only with leguminous plants,
by infesting their roots and forming nodules on them. Non legume nodulated by Rhizobia is
Trema or Parasponia sp.
The nodulated legumes contribute a good deal to the amount of N 2 fixed in the
biosphere, (50-300 kg N/ha) varied with crops.
Clover - 130 kg N/ha
Cowpea - 62 – 128 kg N/ha
Beijerinck first isolated and cultivate a microorganism from the roots of legumes in
1888 and he named this as Bacillus radicola and latter modified as Rhizobium. The name
Rhizobium was established by Frank in 1889.
Legume plants fix and utilise this N by working symbiotically with Rhizobium in nodules
on their roots. The host plants provide a home for bacteria and energy to fix atmospheric N2
and in turn the plant receives fixed N2 (as protein).

Azorhizobium
These genera can produce stem nodules. Stem nodulation has been reported in 3
genera of legumes: Aeschynomene, Neptunia and Sesbania.
Stem nodulating Rhizobium comprises both fast and slow growing types having the
generation time of 3-4 hr and 10 hrs respectively. Those nodulate Aeschynone can cross
inoculate with S. rostrata strains Azorhizobium caulinodans.
- Fix N2 in free living conditions without differentiating into bacteroids.
- Have O2 protection mechanisms, to fix N2 under free living conditions.
- Mode of entry is through lateral root cracks. No infection thread is formed during
colonization.
- Form both stem and root nodules in S. rostrata.
- Gram negative, motile rods.
- Produces root nodules in rice, wheat.

Cross inoculation group (CGI)

It refers the group of leguminous plant that will develop nodules when inoculated
with the rhizobia obtained from the nodules from any member of that legume group. There
are seven cross inoculation groups.
Dr. J.S. Bamboriya

Cross Inoculation Rhizobium spp. Host it can nodulate N2 fixation

Groups kg/ha
Pea group Rhizobium leguminosarum Pea, Lentil, Lathyrus and Vicia 62-132

Clover group R. trifolli Trifolium (red and white clover) 130

Alfalfa group R. melioti Melilotus (Sweet clover), 100-150
Medicago (Alfalfa), Trigonella
(Fenugreek)
Soyabean group R. jopanicum Soyabean 57-105
Cicer group Rhizobium spp. Bengal gram 75-117
Lupini group R. lupine Lupinus 70-90
Cowpea group Rhizobium spp. Mung, Redgram, Cowpea and 57-105
Groundnut
Bean group R. phaseoli Bean

Mechanism of Nitrogen fixation by Legume-Rhizobium

Some plants of leguminosae family form a symbiotic association with bacteria of the genus
Rhizobium which fix atmospheric nitrogen. Specific rhizobia for different legumes infect the root
moving to the root cortex through an infection thread, which results in the formation of a tiny out-
growth called legume “root nodule”. Few plants like “Sesbania rostrata” form such nodule on
the stem as well. Nitrogen is fixed in these nodules. The association of legume with rhizobia is host
specific. The presence of flavonoids and isoflavonoids in the legume root exudates is reported to be
responsible for the host specificity. The flavonoids are also implicated in triggering the process of
nodulation.
Once the rhizobia are delivered into cortical cells, they change their morphology and
physiology to become bacteroid, the actual seat of N2 fixation. The bacteroids are separated from
the plant cell contents by peribacteroid membrane synthesized by plant. Bacteroids have
nitrogenase enzyme and are embedded into leghaemoglobin, a hemeprotein. The role of
leghaemoglobin is to regulate the supply of oxygen to bacteroids and to prevent the exposure of
nitrogenase to O2. The gaseous N2 is converted into NH4+ which diffuses into cytosol to be carried to
shoot for protein synthesis.
The amount of leghaemoglobin and bacteroid production had direct relations with amount of N2
fixed by legumes. The process of N2 fixation is wholly dependent on the activity of enzyme
“Nitrogenase” which is present in bacteroids.
Contribution
1. Direct contribution of N symbiotically with legumes.
2. Residual nitrogen benefit for the succeeding crop.
3. Yield increase is by 10-35%.
4. Improve soil structure.
5. Produces exopolysaccharides.
6. Produces plant growth hormone.
Recommended for legumes (Pulses, oilseeds, fodders)
Promising strains: NGR 6, NC 92, CC 1, CRR 6, CRU 14, COBE 13.
Dr. J.S. Bamboriya

2. AZOTOBACTER
It is a free living N2 fixer, the cells are not prevent on the rhizoplane, but are
abundant in the rhizosphere region. It is classified under the family Azotobacteriaceae. It
requires more of organic matter and depend on the energy derived from the degradation of
plant residues. Beijerinck (1901) was the first to isolate and describe Azotobacter.
Species
Cell size, flagellation, pigmentation and production of extracellular slime are
considered as diagnostic features of these bacteria in distinguishing species.

A. chroococcum : Black to brown insoluble pigment.

A. beijerinckii : Yellow to light brown insoluble pigments
A. vinelandii, A. paspali, : Green fluorescent and soluble pigment
A. macrocytogenes : Pink soluble pigments
A. insignis : Yellow brown pigments

Azotobacter cells are polymorphic, gram negative, form cyst and accumulate Poly
Beta hydroxy butyric acid and produces abundant gum.
Among these species A. chrococcum and A. beijrinekii are most commonly occurring species
in India. However, A.chrococcum found in acid soils while A. beijrinekii found in neutral to alkali
soils.
Morphology

Cell size : Large ovoid cells, size 2.0 – 7.0 x 1.0 – 2.5 µ
Cell character : Polymorphic
Gram character : Negative

Physiology

1. Nature : Chemoheterotrophic, free living

2. C source : Mono, di saccharides, organic acids
3. N source : N2 through fixation, amino acids, NH4+, NO3-
4. Respiration : Aerobic
5. Growth media : Ashby / Jensen's media
6. Doubling time : 3 hours

Benefits
 Ability to fix atmospheric N2 – 20-40 mg BNF/g of C source in laboratory equivalent to
20-40 kg N/ha.
 Production of growth promoting substances like vitamin B, Indole acetic acid, GA.
 Ability to produce thiamine, riboflavin, pyridoxin, cyanogobalanine, nicotinic acid,
pantothenic acid, etc.
 Biological control of plant diseases by suppressing Aspergillus, Fusarium.
Dr. J.S. Bamboriya

• The results from larger number of experiments conducted in last four decades have
shown positive response to Azotobacter application on a crop like cereals, millets,
vegetables, cotton and sugarcane and increased the crop yield by 10 to 30%.

- Recommended for Rice, wheat, millets, cereals, cotton, vegetables, sunflower, mustard
and flowers.

3. AZOSPIRILLUM
Azospirillum was first isolated by Beijerinck (1922) in Brazil from the roots of Paspalum
and named it as Azotobacter paspali and later named as Spirillum lipoferum. Dobereiner and
Day (1976) reported the nitrogen fixing potential of some forage grasses due to the activity
of S. lipoferum in their roots. Dobereiner coined the term "Associative symbiosis" to
denote the occurrence of N2 fixing spirillum in plants. Taxonomy was re-examined and
Tarrand et al. (1978) designated this organism as Azospirillum.

It is an aerobic or micro aerophilic, motile, gram negative bacterium. Non spore former
and spiral shaped bacterium, inhabiting the plant roots both externally and internally. Being
a micro aerophilic organism, it can be isolated on a semi solid malate medium by
enrichment procedures.
Classification
Species: (7) Family – Spirillaceae
1. A. brasilense (C3 plants)
2. A. lipoferum (C4 plants)
3. A. amazonense
4. A. halopraeferens
5. A. irkense
6. A. dobereinerae
7. A. largimobilis
Morphology

1. Cell size : Curved rods, 1 mm dia, size and shape vary

2. Accumulate : PHB
3. Gram reaction : Negative
4. Development of white pellicles : 2-4 mm below the surface of NFB medium

Physiology

1. Nature : Chemoheterotrophic, associative

2. Sole carbon source : Organic acids, L-arabinose, D-gluconate, D-fructose,
D-glucose, sucrose, Pectin
3. N source : N2 through fixation, amino acids, N2, NH4+, NO3-
4. Respiration : Aerobic, Micro-aerophilic
5. Growth media : NFBTB (NFB) medium (Nitrogen free Bromothymol Blue)
 Dr. J.S. Bamboriya

6. Doubling time : 1 hr. in ammonia containing medium 5.5–7.0 hrs. in

malate containing semisolid medium

Mechanism of Action
1. Contribution by BNF
2. Production of PGP substances by bacteria
– Increases root hair development, biomass.
3. Production of PGP substances by plant
– Morphological changes in root cells.
– Increased activity of IAA oxidase
– Increase in endogenous IAA
– Increased mineral and water uptake, root development, vegetative growth and crop
yield.
4. Competition in the rhizosphere with other harmful microorganism.
5. Polyamines and amino acids production.
6. Increased extrusion of protons and organic acids in plants.

Benefits
1. Promotes plant growth.
2. Increased mineral and water uptake, root development, vegetative growth and crop
yield.
3. Inoculation reduced the use of chemical fertilizers (20-50%, 20-40 kg N/ha)
4. Increases cost benefit ratio.
5. Reduces pathogen damage.
6. Inhibit germination of parasitic weeds.
7. Restoration of arid zone, margine mangrove ecosystem.
8. Reduces humic acid toxicity in compost.
- Recommended for rice, millets, maize, wheat, sorghum, sugarcane and co-inoculant
for legumes.

4. BACILLUS

Bacillus (Latin “stick”) is a genus of gram-positive, spore forming, heterotrophic,

facultative anaerobes, free living, rod shaped bacteria, a member of the phylum
Firmicutes, with 266 named species. Bacillus species are ubiquitous in nature, e.g. in soil. They
can occurs in extreme environments such as high pH (B. alcalophilus), high temperature (B.
thermophilus) and high salt concentrations (B. halodurans).
The first commercial bacterial fertilizer, Alinit, was developed from Bacillus spp. and
resulted in a 40% increase in crop yield. Other Bacillus spp.-based products, such as Kodiak

strain (Bacillus subtilis GB03), Quantum-400 (B. subtilis GB03), Rhizovital (Bacillus
amyloliquefaciens FZB42), Serenade (B. subtilis QST713), and YIB (Bacillus spp.), have been
commercialized for improving crop production. Indeed, Bacillus-based bio-fertilizers are more
Dr. J.S. Bamboriya

active compared to Pseudomonas-based fertilizers due to the more effective metabolite

production and spore-forming character of Bacillus spp., which enhances the viability of cells in
commercially formulated products.

5. PSEUDOMONAS

Pseudomonas is a bacteria mostly saprophytic in nature, is found in soil, water and

other moist environment. Pseudomonas is a rod shaped, slender (0.5 to 3.0 μm), strict
aerobe, motile (motile by polar flagella, sometimes more than two flagella may be present),
gram negative bacteria belonging to Pseudomonadaceae family and genus Pseudomonas.
In modern agriculture, imbalanced use of fertilizers, specifically nitrogen and
phosphorous, and indiscriminate use of chemical pesticides has led to depletion in soil fertility
and environmental pollution. Plant growth-promoting rhizobacteria can provide a sustainable
and ecofriendly solution to the problem. Over the last few decades, members of
genus Pseudomonas have been extensively studied for their plant growth promotion and bio-
control of plant pathogens. The beneficial effect of Pseudomonas touches every corner from
nutrient solubilization, plant growth promotion, biological control of insect pest and plant
pathogens, and degradation of certain organic and inorganic pollutants to bioremediation of
heavy metals and pesticides. With worldwide growing concern over environmental pollution and
production of pesticide-free organic crops, Pseudomonas strains have a crucial role to play for
sustaining crop production and soil health in coming decades.

6. FRANKIA (symbiotic association with trees and shrubs)

Representative of the genus Frankia are non-legume, root nodule inducing symbionts
with dicotyledonous plants and are important contributors to nitrogen fixation. They are gram
positive, nitrogen fixing soil actinomycetes capable of forming actinorhizal symbiosis.
Four host infectively groups have been identified amongst Frankia strains such as-
A] Strains which nodulate Casuarinas and Myrica

B] Strains which nodulate Alnus and Myrica

C] Strains which nodulate Elaegnaceae and Myrica and

D] Strains which nodulate only Elaegnaceae

Studies also shows that members of genus Frankia can survive and remain infective on
soils that are devoid of host plants. The host plant of frankia belong to approximately 194
species in 24 genera within 8 families. Owing to their capacity for nitrogen fixation, nodulated
species can grow and improve soil fertility in disturbed sites, and are used in the re-
colonization and reclamation of eroded sand dunes, erosion control and in agroforestry.

7. GLUCONACETOBACTER DIAZOTROPHICUS
It is an endophytic N2 fixer and form to occur on large numbers in roots, stem and
leaf of sugarcane and other sugar rich crops. It was first isolated from sugarcane.
Cavalcanti and Dobereiner (1988) reported this new endophytic N2 fixer and recently
Dr. J.S. Bamboriya

called as from G. diazotrophicus. It can tolerate up to 30% sucrose concentration and pH up

to 3.0. Optimum sucrose concentration is 10-15%.
Produce surface yellow pellicle on semisolid medium. Does not grow at pH 7.0.
Optimum pH is 5.5.
Benefits
- Fixes atmospheric N2
- Production of PG hormones (GA, DAA is double than Azospirillum).
- Suitable for sugar rich crops with acidic pH.

8. ALGAL BIOFERTILIZERS
The agronomic potential of cyanobacterial N2 fixation in rice fields was recognized in
India during 1939 by De who attributed the natural fertility of tropical rice fields to N2 fixing
blue green algae. The rice field ecosystem provides an environment favorable for the growth
of blue green algae with respect to their requirements for light, water, high temperature and
nutrient availability.
Algal biofertilizers constitutes a perpetual source of nutrients and they do not
contaminate ground water and deplete the resources. In addition to contributing 25-30 kg
N ha-1 of biologically fixed N2, they can also add organic matter to the soil, excrete growth
promoting substances, solubilizes insoluble phosphates and amend the physical and
chemical properties of the soil.
Blue green algae are a group of prokaryotic, photo synthetic microscopic
plants, vigorously named as Myxophyceae, Cyanophyceae and Cyanobacteria. They show
striking morphological and physiological similarities like bacteria and hence called as
cyanobacteria.

CYANOBACTERIA
They are the photosynthetic bacteria and some of them are able to fix N2. They
can be divided into two major groups based on growth habit.
a) Unicellular forms and
b) Filamentous forms.
N2 fixing species are from both groups, found in paddy fields, but the predominant
ones are the heterocystous filamentous forms.

Cyanobacteria are not restricted to permanently wet habitats, as they are resistant
to desiccation and hot temperatures, and can be abundant in upland soils. However wet
paddy soils and overlying flood waters provide an ideal environment for them to grow and
fix N2.

Natural distribution
BGA are cosmopolitan in distribution and more widely distributed in tropical zone.
Free living cyanobacteria can grow epiphytically on aquatic and emergent plant as well as in
Dr. J.S. Bamboriya

flood water or on the soil surface. Heterocystous cyanobacteria formed less than 10% of the
population of eukaryotic green algae and the abundance increased with the amount of
available phosphorus and with the pH value over the range 4.0 – 6.5.

The N2 fixing forms generally have a specialized structure known as heterocyst. The
BGA have minimum growth requirement needing only diffused light, simple inorganic
nutrients and moisture. The heterocysts which are modified vegetative cells, because of
their thick walls and absence of photonactin II in photosynthesis, act as ideal sites for N2
fixation under aerobic conditions. Although the nitrogenase is present in vegetative cells, it
remains inactive because of the presence of oxygenic photosynthesis. They built up natural
fertility (C, N) in soil.

N2 fixing BGA: Anabaena, Nostoc, Cylindrospermum, Tolypothrix, Calothrix, Scytonema,

Westiellopsis belonging to orders Nostocales and Stignematales. Many non-heterocystous
forms are also fix N2. eg: But need microaerobic or anaerobic conditions. Gleocapsa fix in
aerobic condition.
The species of BGA, known to fix atmospheric N2 are grouped as 3 groups.
(i) Heterocystous – aerobic forms
(ii) Aerobic unicellular forms
(iii) Non-heterocystous, filamentous, micro aerophilic forms.

The blue green algal culture's composite inoculum consists of Nostoc, Anabaena,
Calothrix, Tolypothrix, Plectonema, Aphanotleca, Gleocapsa, Oscillatoria, Cylindrospermum,
Aulosira and Scytonema.
The main taxa of N2 fixing cyanobacteria
Group Genera DNA
(mol % GC)
Group-I. Unicelluar: single cells Gloeothece, Gloeobacter, Synechococcus, 35-71
or cell aggregates Cyanothece, Gloeocapsa, Synechocystis,
Chamaesiphon, Merismopedia

Group-II. Pleurocapsalean: Dermocarpa, Xenococcus, 40-46

reproduce by formation of small Dermocarpella, Pleurocapsa, Myxosarcina,
spherical cells called baeocytes Chroococcidiopsis
produced through multiple
fission.
Group-III. Oscillatorian: Oscillatoria, Spirulina, Arthrospira, 40-67
filamentous cells that divide by Lyngbya, Microcoleus, Pseudanabaena.
binary fission in a single plane.
Dr. J.S. Bamboriya

Group-IV. Nostocalean: Anabaena, Nostoc, Calothrix, Nodularia, 38-46

filamentous cells that Cylinodrosperum, Scytonema
produce Heterocysts

Group-V. Branching: cells Fischerella, Stigonema, Chlorogloeopsis, 42-46

divide to form branches Hapalosiphon

Contributions of algal biofertilizer

- Important component of organic farming.
- Contribute 20 – 25 kg N ha-1.
- Add organic matter to the soil.
- Excrete growth promoting substances.
- Solubilize insoluble phosphates.
- Improve fertilizer use efficiency of crop plants.
- Improve physical and chemical properties of soil.
- Reduce C:N ratio.
- Increase the rice yield by 25-30%.
It increases FUE of the crop plants through exudation of growth promoting
substances and preventing a part of applied fertilizer N from being lost.

I. PHOSPHATE SOLUBILIZING MICROORGANISMS

Introduction
Though most soils contain appreciable amounts of inorganic P, most of it being
insoluble forms, cannot be utilized by crops unless they are solubilized. Soils also contain
organic P that could not be utilized by plants only when it is mineralized. Phosphate
solubilizing microorganisms not only able to solubilize insoluble forms of inorganic P but are
also capable to mineralize organic forms of P, thus improving the availability of native soil P
making their P available to plants. PSM can also solubilize P from rock phosphate (RP), slag
or bone meal making their P available to plants.
Thus PSM biofertilizer being economical and environmentally safe offers a viable
alternative to chemical fertilizers.
Microorganisms involved
Many microorganisms can solubilize inorganic phosphates, which are largely
unavailable to plants. Microbial involvement in solubilization of inorganic phosphate was first
shown by Stalstron (1903) and Sacket et al. (1908) gave conclusive evidence for bacterial
solubilization of RP, bone meal and TCP.
Various bacteria and fungi reported to solubilize different types of insoluble
phosphates. Not only solubilizes but also mineralize organic P compounds and release
orthophosphates.
In general PSM constitute 0.5 – 1.0% of soil microbial population with bacteria and
Dr. J.S. Bamboriya

out numbers the fungi by 2 – 150 folds. But bacteria may lose the P solubilizing ability while
sub culturing and fungi do not lose. Among bacteria, aerobic spore forming bacteria are
more effective P solubilizers. A. awamori & A. niger, Bacillus polymixa & Penicillium striata are
effective in solubilization of phosphate.

II. MYCORRHIZAE
Mycorrhiza (fungus root) is the mutualistic association between plant roots and
fungal mycelia. Frank (1885) gave the name "mycorrhiza" to the peculiar association
between tree roots and ectomycorrhizal fungi. 95% of the plant species form mycorrhizae.
It can act as a critical linkage between plant roots and soil. This association is characterized
by the movement of plant produced carbon to fungus and fungal acquired nutrients to
plants. Mycorrhizal fungi are the key components of the rhizosphere are considered to have
important roles in natural and managed ecosystems.
Types of mycorrhiza
Mycorrhizal associations vary widely in structure and function. Two main groups of
mycorrhizae are recognized; the ectomycorrhizae and endomycorrhizae, although the rare
group with intermediate properties, the ectendotrophic mycorrhizae.
1. Ectomycorrhiza
The fungal hyphae form a mantle both outside the root and within the root in the
intercellular spaces of the epidermis and cortex. No intracellular penetration into epidermal
or cortical cells occurs, but an extensive network called the Harting net is formed between
these cells. Sheath or Mantle increases the surface area of absorbing roots and offers
protection to the roots. Harting net can act as storage and transport organ for P.
Ectomycorrhizae are common on trees, including members of the families pinaceae
(Pin, Fir, Spruce, Larch, Semlock), Fagaceae (Willow, Poplar, Chesnut), Betulaceae (Birch,
Alder), Salicaceae (Willow, Poplar) and Myrtaceae.
The fungi forming Ectomycorrhizal association are coming under Basidiomycotina and
Ascomycotina. eg: Laccaria laccata, Suillus, Rhizopogan, Amanita and Boletus.
2. Endomycorrhizae
Endomycorrhizae consist of three sub groups, but by far the most common are the
Arbuscular Mycorrhizal fungi. Fungi under AM are the members of Endogonaceae and they
produce an internal network of hyphae between cortical cells that extends out into the soil,
where the hyphae absorb mineral salts and water. This fungus do not form an external
mantle but lives within the root. In all forms, hyphae runs between and inside the root cells
which includes,
Ericoid mycorrhiza - Associated with some species of Ericaceous plants
Orchid mycorrhiza - associated with orchid plants
Arbuscular mycorrhiza - associated with most of the plant families
Dr. J.S. Bamboriya

Arbuscular Mycorrhizal fungi

The most important one is AM.
AM, an endomorphic mycorrhizae formed by the aseptate phycomycetous fungi are
associated with majority of agricultural crops, growing under broad ecological range.
Class : Zygomycotina
Order : Endogonales
Family : Endogonaceae
150 species of AMF are known.

Colonization Process
Roots do not show visual morphological changes due to AM colonization. AM fungal
infection into a host occurs by germination of spore, hyphal growth through soil to host
roots, penetration of host roots and spread of infection inter and intracellularly in the root
cortex. Colonization occurs under two phases: (1) Extra matrical phase and (2) Intra radical
phase.
Extra matrical phase: Events occurring outside the root after the germination of
chlamydospores. Mycelium explores larger soil volume. Fungal growth can be 80-130 times
the length of root. Extra matrical hyphae (EMH) are larger in diameter than inner hyphae.
Once the fungus recognises the plant, appresorium is formed in the host roots and
penetration occurs via the appresorium. EMH ends with resting spores in soil.

Intra radical phase: Events occurring inside the root cortex. After penetrating the cortex,
the fungus may produce intercellular as well as intracellular hyphae in the cortical cells.
Forms two morphological structures namely arbuscules and vesicles inside the cortical cells.

Arbuscules: are the first formed structures after the hyphal entry into the cortical cells.
Arbuscules are the fine dichotomously branched hyphal filaments look like little trees.
Arbuscules start to form approximately 2 days after penetration. They are considered as the
major site of exchange between the fungus and host root. They are short lived (4-13
days) and degenerate.

Vesicles: Following the formation of arbuscules, some species of fungi also form vesicles in
the roots. Terminal or intercallery hyphal swellings of the hyphae called vesicles. Vesicles
contain lipids and cytoplasm. They act as P storage organ and they ever be present in the
root. Size of the vesicles is about 30-100 µm. In vesicles P can be accumulated as
polyphosphates.
EMH, vesicles and Arbuscules play a key role in nutrient transfer particularly in mobilisation
of phosphorus.
Dr. J.S. Bamboriya

Mechanism of action
The beneficial effect on plant growth and yields following inoculation with VAM is
attributed to
(i) improved mineral nutrition, especially P (P, Zn, Cu, K, S, NH4)
(ii) Mobilization of nutrients through greater soil exploration.
(iii) Protection of host roots against pathogen infection.
(iv) Improved water relation
(v) Better tolerance to stress like salinity, heavy metal pollution
(vi) Protection against transplantation shock.

Continued…..

Arbuscules vesicles.
Dr. J.S. Bamboriya

Reasons for Enhanced P uptake by AM Fungi

- Physical exploration of soil.

- Higher affinity towards P

- Lower threshold concentration

- Rhizosphere modification

- Differences in anion and cation absorption due to exudation pattern.

- Siderophore production.

- Selective stimulation of microorganisms in the rhizosphere.

- Increased hyphal area for absorption (EMH).

- Absorb and transport P beyond the depletion zone around the root.

- P absorption by EMH is 1000 times faster than normal hyphae and 3-4 times
greater.

Disease resistance

- Resist the parasitic invasion and minimises the loss.

- Mycorrhizal roots harbour more actinomycetes.

- Mycorrhizal roots have elevated levels of phenols, while offers resistance to

fungal hydrolytic enzymes.

- Mycorrhizal infection stimulates biosynthesis of phytoalexins.

Dr. J.S. Bamboriya

MECHANISM OF PHOSPHATE SOLUBILIZATION

Different mechanisms were suggested for the solubilization of inorganic phosphates.

 Production of organic acids

 Chelating effect

 Production of inorganic acids

 Hydrogen sulphide production (H2S)

 Effect of carbon dioxide

 Proton extrusion
 Siderophore production

Siderophores, bind iron tightly to prohibit its reaction with soluble phosphate and rather
help release PO4 fixed as ferric phosphate. It is important in acid soils, where ferric PO4 is
one of the major forms.
The extent of PO4 solubilization depends on the type of organisms involved. The
genus Bacillus showed maximum activity followed by Penicillium and Aspergillus.
Streptomyces was least effective.
The principal mechanism for mineral phosphate solubilization is the production of organic
acids and phosphatases play a major role in the mineralization of organic phosphorus in the soil.
It is generally accepted that the major mechanism of mineral phosphate solubilization is the
action of organic acids synthesized by soil microorganisms.
Several soil bacteria and fungi, notably species of Pseudomonas, Bacillus, Penicillium and
Aspergillus etc. sectere organic acids and lower the pH in their vicinity to bring about dissolution
of bound phosphates in the soil. Gluconic acid seems to be the most frequent agent of mineral
phosphate solubilization. Also, 2-ketogluconic acid is another organic acid identified in the
strains with phosphate solubilizing ability.
Strains of Bacillus were found to produce mixtures of lactic, isovaleric, isobutyric and
acetic acids. Other organic acids, such as glycolic, oxalic, malonic and succinic acid have also
been identified among phosphate solubulizers. Strains from the genera Pseudomonas, Bacillus
and Rhizobium are among the most powerful phosphate solubulizers.

MECHANISM OF POTASSIUM SOLUBILIZATION

Potassium is a macronutrient taken up by plants in the large quantities. Its behavior in

the soil is impacted by soil cation exchange and mineral weathering, rather than microbial
activity. It is known that potassium solubilizing bacteria (KSB) can solubilize K-bearing minerals
and convert the insoluble K to soluble forms of K which is available to plant uptake.

Many bacteria such as-

Bacillus mucilaginosus, B. edaphicus, Acidothiobacillus ferroxidans, Paenibacillus spp.
and B. circulans have capacity to solubilize K minerals (e.g. biotite, feldspar, illite, muscovite,
Dr. J.S. Bamboriya

orthoclase and mica).

KSB are usually present in all soils, although their number, diversity and ability for K
solubilization vary depending upon the soil and climatic conditions. KSB can dissolve silicate
minerals and release K through the production of organic and inorganic acids, acidolysis,
polysaccharides, complexolysis, chelation and exchange reactions.
It is generally believed that microorganisms contribute to the release of K + from K-
bearing minerals by several mechanisms. Released H+ can directly dissolve the mineral K as a
result of slow releases of exchangeable K, readily availbale exchangeable K.
As occurs in the case of P solubilization, the major mechanism of K mineral solubilization
is by production the organic and inorganic acids and production of protons (acidolysis
mechanism) which are able to convert the insoluble K (mica, muscovite, and biotite feldspar) to
soluble forms of K, easily taking up by the plant.
The types of various organic acids such as oxalic acid, tartaric acids, gluconic acid, 2
ketogluconic acid, citric acid, malic acid, succinic acid, lactic acid, propionic acid, glycolic acid,
malonic acid, fumaric acid, etc. have been reported in KSB, which are effective in releasing K
from K-bearing minerals. It has also been known that the type of the organic acid produced by
KSB may be different. Among the different organic acids involved in the solubilization of
insoluble K, tarteric acid, citric acid, succinic acid, a-ketogluconic acid, and oxalic acid are the
most prominent acids released by KSB.
Microbial decomposition of organic materials also produces ammonia and hydrogen
sulfide that can be oxidized in the soil to form the strong acids such as nitric acid (HNO3) and
sulfuric acid (H2SO4). Hydrogen ions displace K+, Mg2+, Ca2+, and Mn2+ from the cation-
exchange complex in a soil. In addition to decreasing soil pH, organic acids produced by KSB
can release of K ions from the mineral K by chelating (complex formation) Si 4+, A13+, Fe2+, and
Ca2+ ions associated with K minerals.
Microorganisms including KSB can have a considerable role in proving K to plant by
storing K in their biomass (a significant quantity of fixed K), which is potentially available to
plants, It has been reported that the production of various extracellular polymers (primarily
proteins and polysaccharides) can also be led to release of K from K-bearing minerals for plant
uptake
The most important mechanisms known in K mineral solubilization by KSB are
(i) By lowering the pH
(ii) By enhancing chelation of the cations bound to K
(iii) Acidolysis of the surrounding area of microorganism
Dr. J.S. Bamboriya

Production technology: Strain selection, sterilization, growth and

fermentation, mass production of carrier based and liquid biofertiizers

Mass Production and Quality Control:

A specific medium is constituted for the growth of specific or specific group of
microorganisms. During constitution of such medium, one or few additional components are
added and /or one or few components are deleted from the general media depending upon
the requirement of the specific microorganism. Again, according to the physical appearance,
media-are of two types: a) Liquid media and b) Solid media. The liquid medium is solidified by
the addition of solidifying agent- agar-agar. Liquid medium can harbor bacterial growth
suspended in the media, whereas solid medium harbors. Microbial growth on the surface.
Solid media may be prepared as slant or plate. Preparation of Starter Culture: The starter
culture is a little amount of bacterial suspension, which is added to the medium to start the
growth of that bacterium. Twin flask is a pair of flasks of identical size joined together by a
latex tube. For the preparation of starter culture, this type of flask is used. Each flask contains
a side arm below the neck position. The latex tube joining the two flasks is held together by
this glass tube. The benefit of the use of the twin flask is that contamination can be avoided.
Fermentation: A fermenter is a device in which the optimum conditions for the microbial
growth and activity is established artificially. This device may be used for the production of
microbial metabolites such as antibiotics or enzymes; it may also be used for the growth of
microorganisms i.e. production of microorganism itself.
Sterilization of the fermenter:
Fermenter is a metallic vessel for moist sterilization of any article. The principle of
moist sterilization lies in the fact that when water is boiled in a closed system, the water vapor
produced due to boiling accumulates within the vessel and increases the inside pressure. Thus
the boiling point of water increases beyond 100 0C, which is the boiling point of water in
normal atmospheric pressure. In this condition, the steam, released from the boiling water is of
higher temperature. If any article placed in this vessel in such condition, the high temperature
destroys the microorganisms present in or on the article.
Inoculation, Growth, Quality Testing and Termination of growth:
Inoculation means addition of starter culture to the medium in the fermenter. For the
production of microbial biofertilizers a small amount of suspension of the desired bacterium in
pure form is inoculated to the medium. Care should be taken to maintain the quality of starter
culture, as extent of purity (no contaminants should be allowed), size of the starter culture (in
terms of culture volume and density of cell) and stage of growth. Greater the size of starter
culture, lessen the chance of contamination. If the starter culture is inoculated in its log phase,
rapid initial growth will occur. Maintenance of proper physical and chemical environment inside
the fermenter is essential for proper growth of microorganism. Quality testing, in this case, is
enumeration of cell density and its purity in the broth. When the cell density reaches the
desired level, growth is terminated and the culture is ready for mixing with carrier. The time
period required for optimum cell density is thus standardized.
Dr. J.S. Bamboriya

Laboratory setting and operations

Aseptic techniques:
Working in absence of contaminants is very important thing. Aseptic technique is
essential for all pathology work and must be thoroughly practiced and mastered. Insect
pathogenic fungi or bacterial cultures for insect pathology must be pure. This means that they
must be free of any living microbes other than the one required. The presence of unwanted
microorganism (fungi or bacteria) is known as contamination and the microbes responsible for
contamination are referred to as contaminants. We use aseptic technique so that we can
handle, or manipulate microorganisms without appearance of contaminants into the culture.
Aseptic technique also helps to protect the operator from potential infection from pathogenic
organisms.
Always use aseptic technique when handling microorganisms and also when preparing
microbiological media in which to grow these organisms.

Sterilization:
Elimination of all viable microbes from a material is known as sterilization. Sterilization
is nonselective process. It is very important stage for any microbiological work. The success of
proper sterilization ensures quality of final product. All equipment and media to be used
during the handling of the microorganism must be sterile.
Disinfection:
Disinfection is a way to reduce the contaminant load. It removes potentially infective
microbes, but does not render the object sterile. Many different methods of sterilization are
being used. The sterilization method you use depends on the equipment you have and what it
is you are sterilizing. As a general rule, the following methods are appropriate.
Laboratory growth media
Sterilize as above using wet heat sterilization or dry heat sterilization in an oven (see
lab techniques) at 160°C for 1-2 hours. If you have no autoclave, pressure cooker or oven,
you can use certain chemical agents such as strong acids or alkalines, phenols or ethylene
oxide. All chemical methods are potentially hazardous to the operator and should be avoided
where possible.
 Sterilization of carrier material is essential to keep high number of inoculant Bacteria on carrier
for long storage period.
 Gamma-irradiation is the most suitable way of carrier sterilization, because the sterilization
process makes almost no change in physical and chemical properties of the material. (In brief,
carrier material is packed in thin-walled polyethylene bag, and then gamma-irradiated at 50
kGy (5 Mrads).
 Another way of carrier sterilization is autoclaving. Carrier material is packed in a partially
opened, thin-walled polypropylene bags and autoclaved for 60 min at 121 °C. It should be
noted that during autoclaving, some materials changes their properties and produce toxic
substance to some bacterial strains.
Dr. J.S. Bamboriya

A] Carrier based Biofertilizer Production:

1) Preparation of Carrier –
At present, biofertilizers are supplied as carrier-based microbial inoculants which
are added to the soil to enrich the soil fertility. The carrier is a medium that can carry the
microorganisms in sufficient quantities and keep them viable under specified conditions,
easy to supply to the farmers. The use of ideal carrier material is necessary in the
production of good quality biofertilizer. Finely powdered peat, lignite or soil + compost or
cellulose powder may be used as carrier.
A good carrier should have the following qualities:

 Contained high organic matter, more than 60 %.

 Low soluble salt content, less than 60%.

 High moisture holding capacity – 150 to 200 % by weight.

 Non-toxic to microorganisms;

 Easy to sterilize effectively;

 Available in adequate amounts and low-cost;

 Provide good adhesion to seeds;

 Has good buffering capacity;

Carrier provides a nutritive medium for growth of bacteria and prolongs their survival
in culture as well as on inoculated seed. The carriers are powdered to 250 to 300 mesh
about 75 micron pore size. If peat is used of 300 meshes is neutralized with 1 % CaCO3 and
sterilized at 15 PSI for 4 hours in autoclave.

2) Preparation of Inoculants in Powder Form –

In the preparation of inoculants moisture essential that the appropriate moisture
content of a specific carrier should be determined. The ideal moisture range must be set to
consider the bacterial growth, maximum population attainable after mixing, bacterial survival
and anticipated moisture loss from the package over the period of shelf life 5 – 6 months.
Usually about one part of broth (by weight) required two parts of dry carrier. Final
moisture content varies from 30 to 50 %, depending on quality of carriers. After adding broth
culture to carrier powder in 1 : 2 proportion by weight, it is kept for curing at room
temperature 28˚ C for 5 to 10 days in 10 cm deep trays of convenient size.
After curing it is sieved to disperse the concentrated packets by breaking lumps. It is
then packed in polythene bags of 0.5 mm thickness leaving 2/3 space open for aeration of
the bacteria.

B] Liquid Biofertilizer Production:

At present, Biofertilizers are supplied to the farmers as carrier based inoculants. As
an alternative, liquid formulation technology has been developed which has more advantages
than the carrier inoculants.
The advantages of Liquid Bio-fertilizer over conventional carrier based Bio-fertilizers are listed
below:
Dr. J.S. Bamboriya

 Longer shelf life-12-24 months.

 No contamination and no loss of properties due to storage upto 45° c.
 Greater potentials to fight with native population.
 High populations can be maintained more than 109 cells/ml upto 12 months to 24
months.
 Easy identification by typical fermented smell.
 Cost saving on carrier material, pulverization, neutralization, sterilization, packing and
transport.
 Quality control protocols are easy and quick.
 Better survival on seeds and soil and very much easy to use by the farmer.
 No need of running Bio-fertilizer production units throughout the year.
 Dosages is 10 time less than carrier based powder Bio-fertilizers.
 High commercial revenues and High export potential.
 Very high enzymatic activity since contamination is nil.

1) Preparation of Starter Culture –

Pure culture of efficient strain of N2 fixing, phosphorus solubilizers and potash
solubilizers grown on respective agar medium in petri-plate or slants. A loopful inoculant
from petri-plates or slants is transferred in a 250 ml Liquid medium/ broth of conical flasks.
The flasks are kept on shaker at 260 rpm for 72 to 96 hrs (3 to 4 days). If shaker is not
available incubate it at 28˚C for 5 to 6 days.

2) Preparation of Liquid Biofertilizer –

 Prepare liquid medium/broth for respective efficient strain of N 2 fixing, phosphorus
and potash solubilizers.

 Cell protectants viz. trehalose dissolved separately and add in to broth before
sterilization.
 The sterilization of broth is to be carried out at 15 PSI for 15 minutes.

 Separately sterilized saturated stock solution of glucose and arabinose.

 This stock solution inoculated with pure starter culture at 10 ml/litre under aseptic
condition in conical flasks.
 Incubate the flask at 28˚ C for 2 to 5 days.

 Sterilize glycerol added to the inoculated broth.

 This broth fill up in previously sterilized polypropylene bottles and make it air tight by
screw cap.
 Labelled it properly with product of specific strain for which crop it is used application
instructions, expiry date and quantity required for seed treatment or quantity required
for soil application.
Dr. J.S. Bamboriya

SPECIFICATIONS AND QUALITY CONTROL OF BIOFERTILIZERS

Indian Standard Institution (I.S.I.) now known as a Bureau of Indian Standards (B.I.S)
formulated an agriculturally useful microorganisms sectional committee specified the Indian
Standard for Rhizobium Inoculants (IS : 8268–1976) and Azotobacter Inoculants (IS : 9138–
1979). These specifications are as below. ISI standards specified for Rhizobium and
Azotobacter Inoculants.

Sr. No. Parameters Rhizobium Azotobacter

1 Cell number at the10 /gram of carrier within 15107/gram of carrier within 15
8

time of manufacture days of manufacture. days of manufacture.

2 Cell number at the 107/gram of carrier within 106/gram of carrier within
time of supply 15 days before expiry date 15 days before expiry date
3 Expiry Date 6 months from the date of 6 months from the date of
Manufacture manufacture
4 Permissible No contamination at 108No contamination at 107
Contamination Level dilution. dilution.
5 Ph 6.0 to 7.5 6.5 to 7.5
6 Strain Should be checked Nothing specific.
serologically.
7 Corner Should pass through 150- Should pass through 160
212 micron IS sieve. micron IS sieve.
8 Nodulation Test Should be positive. -
9 Nitrogen fixation Above 20 mg/g of glucose. Not less than 10 mg/g of
sucrose.

Quality control measures as per ISI specification. Biofertilizers should be assessed

for the following quality standards.

1) Inoculant should be carrier based or liquid based.

2) The inoculant should contain minimum of 108 viable cells of bioinoculant / gram of
carrier on dry weight basis when it is started at 25 to 30 ˚C.

3) The inoculant should have a maximum of 6 months of expiry period from

manufacture in case of carrier based and 9 months in case of liquid based.
4) The pH of inoculant should be in the range of 6.0 to 7.5.

5) Inoculant show effective nodulation/ nitrogen fixed on particular crop before expiry
date.

6) The carrier material should be in the form of powder i.e. peat, lignite, peat soil and
humus.

7) Inoculant should be packed in 50-75 micron low density polythene bags (LDP bags).
Dr. J.S. Bamboriya

DIFFERENT METHODS OF APPLICATION OF BIOFERTILIZERS

There are two types of biofertilizer.
a) Carrier based (powder form) biofertilizer
b) Liquid biofertilizer.
A] Application Methods of Carrier Based Biofertilizers

1) Seed Treatment –

This is the most common practice of applying biofertilizers. In this method, the
biofertilizers are mixed with 10% solution of jaggary. The slurry is then poured over the seeds
spread on a cemented floor and mixed properly in a way that a thin layer is formed around
the seeds. The treated seeds should be dried in the shade overnight and then they should be
used. Generally, 750 grams of biofertilizer is required to treat the legume seeds for a one-
hectare area.

2) Seedling Treatment –

Generally this method is used in seedlings of transplanted crops like chilli, vegetable
seedlings, onion, etc. The seedling treatment involves following steps:
The seedling roots of transplanted crops are treated for half an hour in a solution of
biofertilizers before transplantation in the field. In this method, the seedlings required for one
acre are inoculated using 2–2.5 kg biofertilizers. For this, a bucket having adequate quantity
of water is taken and the biofertilizer is mixed properly. The roots of the seedlings are then
dipped in this mixture so as to enable the roots to get inoculum. These seedlings are then
transplanted.

3) Soil Application

When biofertilizer application to seed or seedlings is not possible, then soil application
method is followed. Soil application method involves following steps:

a. Prepare the mixture of 2 to 4 kg biofertilizer in 40 to 60 kg sieved well decomposed

compost.
b. Broadcast the mixture on acre area at the time of sowing or 24 hours before sowing.
c. Soil application for fruit crops, 5 kg FYM + 25 gram PSB + 25 gram Azotobacter + 25
gram Trichoderma is applied per plant.

B] Application Methods of Liquid Biofertilizer:-

1) Seed Treatment –

Treatment 1 kg seed with 25 ml of liquid biofertilzers and seed are kept for 10
minutes. Then dry the seeds in shade and sow as early as possible preferably during morning
or evening hours for the seeds like cotton (hard coat) treatment should be carried out
overnight.

2) Seedling Treatment –

Root system of seedlings is to be dipped in liquid biofertilizer for 8-10 minutes so that
root system get high population of bioinoculant. The liquid biofertilizer 500 ml is sufficient for
Dr. J.S. Bamboriya

seedling treatment of one acre.

3) Soil Application –

First 100 ml liquid biofertilizer diluted in 5 litre of water and then fix such solutions in
50 kg cowdung and 5 kg rock phosphate. Keep this mixture overnight and next day apply
the mixture over one acre.

4) Soil Pelleting –
Take 2 kg fine sieved soil sprinkle 25 ml liquid biofertilizer on it. Keep this mixture
overnight. Take about 8 to 10 kg seed and mix with mixture. Then allow the seeds to dry in
shade before sowing in the field.

5) Foliar Spray –

Dilute 3 litre liquid biofertilizer in 200 litres of water and spray the solution on one
acre crop preferably in the evening.

6) Drip Irrigation –

2 litre liquid biofertilizer is given through drip irrigation for one acre area.
Dr. J.S. Bamboriya

BIOFERTILIZERS: STORAGE, SHELF LIFE, QUALITY CONTROL AND MARKETING

Storage of Biofertilizer
 The packet should be stored in a cool place away from the heat or direct sunlight.
 The packets may be stored at room temperature or in cold storage conditions in lots in plastic
crates or polythene / gunny bags.
 The population of inoculant in the carrier inoculant packet may be determined at 15 days
interval. There should be more than 109 cells/g of inoculant at the time of preparation and 107
cells/g on dry weight basis before expiry date.

Shelf Life of Biofertilizers

 In general, biofertilizers are living microorganisms, unlike chemical fertilizers; they
themselves are not the source of nutrients but can help the plants in accessing the nutrient
available in its surrounding environment.
 Viability of these organisms during production, formulation, storage, transportation/
distribution and field application is directly related to plant growth promoting potential of a
biofertilizer formulation.
 The complaint from farmers regarding the efficiency of biofertilizer is not uncommon and
improper storage and longer duration between production and field application could be the
best explanation for such incidents.
 Hence, improved shelf life could be the key for further popularization of biofertilizer
application.

Strategies used for Maximum Viability

(i) Optimization of biofertilizer formulation,
(ii) Application of thermo tolerant/drought tolerant/ genetically modified strains
(iii) Application of liquid biofertilizer
 For convenience of application, a carrier material is used as a vehicle for the microorganisms
to be used as biofertilizer. Moreover, such materials may have a role in maintaining the
viability (shelf-life) of the microorganisms prior to its release into the field as well as they
also provide a suitable micro environment for rapid growth of the organisms upon their
release.
 A carrier could be a material, such as peat, vermiculite, lignite powder, clay, talc, rice bran,
seed, rock phosphate pellet, charcoal, soil, paddy straw compost, wheat bran or a mixture
of such materials. Liquid biofertilizer formulation could be considered as one potential
strategy for improving the shelf-life of biofertilizer.
 Unlike solid carrier based biofertilizers, liquid formulations allow the manufacturer to include
sufficient amount of nutrients, cell protectant, and inducers responsible for cell/spore/cyst
formation to ensure shelf-life.
 The shelf-life of common solid carrier based biofertilizers is around six months; however, it
could be as high as two years for a liquid formulation.
 Further, solid carrier based biofertilizers are less thermo-tolerant whereas; liquid
formulations can tolerate the temperature as high as 55°C.
Marketing Plan / Strategy:
Some of the marketing strategies as suggested below may work strongly in the
Dr. J.S. Bamboriya

marketing of bio fertilizers:

Market Segmentation & Product Positioning;
The segmentation is primarily dividing market into various groups of buyers. First of
all the organic producers will be the most important buyers as organic production without bio
fertilizers will not be possible. Among nonorganic producers, the market can be segmented
by “specific crop grower (Fruits/ Vegetable/Oilseed/ Pulses/Sugarcane/Cereals), institutional
buyers (Cane/ Tea/ Coffee/ cotton/ oilseeds/pulses federations & research-farms, SFCI,
Agro-industries etc). Bio fertilizers can be easily positioned as environmental friendly growth
enhancer manure with long term benefits such as enrichment of soils, similarly other benefits
for example:
(a) “Save cost through reduced dosage of chemical fertilizers”
(b) “Improves resistance power against disease”
(c) “Enhance sugar recovery percent in sugarcane” etc. need to be highlighted.
Pricing;
Being price sensitive input, the pricing needs to be kept at penetrative level, slightly
lower than the competitors. However, real advantage to the units will come from reduction in
logistics costs being near to the consuming areas. Publicity & Training the POS (Point of
Sales) material giving details of proper method of application must be made available to all
dealer/ distributors and also needs to be ensured that product is displayed visibly. To deploy
Extension Executives for promoting bio fertilizers with constant visits and developing a close
connect with farmers and undertaking demonstrations with its replication in nearby villages.
Marketing Linkages;
With the promotion of alternate sources of nutrition management, there is already
awareness among the farmers related to bio fertilizer and becoming popular gradually. Now
Bio fertilizers of many brands are readily available in the market through the regular dealer/
distributor network. Many of these are produced outside Odisha. So it is not very difficult to
promote the appropriate crop specific products manufactured inside the state. Moreover these
products will have added advantage of lower transportation and marketing cost. The
marketing of the products can therefore be done through the existing marketing network. The
farmer co-operatives and farmer groups can also be contacted for bulk selling. The Marketing
linkages with Technology providers like “Drip Irrigation” producers may be initiated as Liquid
bio-fertilizers have got tremendous potential as its application through this technology.
Similarly, tie-up with Export oriented crops like turmeric, ginger, spices, fruits and Vegetable
growers could be undertaken as the organic products are being preferred by this segment due
to compulsion of importing nation’s condition of permissible limits of chemical residues in the
produce. Govt. of Odisha is also buying bio fertilizer in bulk for various crops under various
schemes and the local products are given preference for the same. This market has to be
tapped. There are Sugar Industries who could also be a bulk buyer for Acetobacter and PSM /
Potash mobiliser or Zinc & sulphur Solubilisers.
Dr. J.S. Bamboriya

FACTORS INFLUENCING THE EFFICACY OF BIOFERTILIZERS

The most important factors affecting field performance of biofertilizers are;

1. Available moisture in the field
2. Microbial population and compatability
3. Soil organic matter
4. Inorganic nutrients and pesticide application
5. Soil characteristics like salinity, acidity, drought, waterlogging, etc.
6. Doses and method of application
7. Crop specificity
8. Soil condition before and immediately after application
9. Soil temperature and rainfall

TIPS TO GET GOOD RESPONSE TO BIOFERTILIZER APPLICATION

 Biofertilizer products must contain an appropriate population of good effective strains and
should be free from contaminating microorganisms.
 Select the right combination of biofertilizers and use before the expiry date.
 Use the suggested method of application and apply at appropriate time as per the
information provided on the label.
 For seed treatment, adequate adhesive should be used for better results.
 For problematic soils, use corrective methods like lime or gypsum pelleting of seeds or
correction of soil pH by use of lime.
 Ensure supply of phosphorus and other nutrients.

PRECAUTIONS BEFORE BIOFERTILIZER APPLICATION

 Biofertilizer packets need to be stored in a cool and dry place away from direct sunlight and
heat.
 Right combinations of biofertilizers have to be used.
 As Rhizobium is crop specific, one should use it for the specified crop only.
 Other chemicals should not be mixed with the biofertilizers.
 When purchasing, one should ensure that each packet is provided with all necessary
information like name of the product, name of the crop for which it is intended, name and
address of the manufacturer, date of manufacture, date of expiry, batch number and
instructions for use.
 The packet has to be used before its expiry, only for the specified crop and by the
recommended method of application.
 Biofertilizers are live products and require care in their storage.
 Both nitrogenous and phosphate biofertilizers are to be used to get the best results.
 It is important to use biofertilizers along with chemical fertilizers and organic manures.
 Biofertilizers are not a replacement of fertilizers but can supplement plant nutrient
requirements.
Dr. J.S. Bamboriya