This PPT is about Biofertilizers & Their effects in Agriculture and Environment. Hope you like it.

1. Biofertilizers
Agriculture
Microbiology

2. Introduction
Biofertilizers are the biological substances that can enhance plant nutrition by mobilizing
or increasing nutrient availability in the soil. The main source of biofertilizers are
bacteria, fungi and cyanobacteria.

3. Introduction

4. Production process of biofertilizers

5. Production process of biofertilizers

6. Biofertilizers vs Chemical
fertilizers
Characteristics Biofertilizer Chemical Fertilizer
Definition Biofertilizers are the biological substances
that can enhance plant nutrition by
mobilizing or increasing nutrient availability
in the soil.
Chemical fertilizers are chemical-based
substances consisting of one or more nutrients
required for the enhancement of plant growth
and soil fertility.
Composition Composed of natural materials that are
extracted from animals and plants.
composed of non-organic and artificially
cultivated elements.
NPK Ratio –
Nitrogen
Phosphorus
Potassium Ratio
Very Low. High.
Shelf-Life Shorter shelf life. Longer shelf life.
Soil Life Makes the soil healthier and more fertile. Soil life will not be enriched or stimulated.
Examples Rhizobium, Azotobacter, Azospirilium and
blue green algae (BGA)
(NH₄)₂SO₄, NH₄NO₃, CO(NH₂)₂ & NH4Cl.

7. Why are biofertilizers preferred over chemical
fertilizers?
1. Less harmful then Chemical fertilizers.
2. They contain organic materials while chemical fertilizers are made up of
harmful chemicals.
3. Production process is less difficult then chemical fertilizers.
4. It Supports the growth of nitrogen-fixing bacteria where chemical fertilizer
destroys the growth of nitrogen-fixing bacteria as it contains high acid
content.
5. More biodegradable, sustainable, and environmentally friendly then Chemical
fertilizers.
6. Biofertilizers ensure an airy soil structure, where chemical fertilizers lead to
soil acidification.
7. Overuse of chemical fertilizer causes soil pollution, where biofertilizer
increases soil fertilization.
8. Biofertilizer provides almost all nutrients but chemical fertilizer supply only
one specific nutrient.
9. Production & manufacture cost is lower than chemical fertilizer.

8. Biofertilizer preparation
Criteria for strain selection of biofertilizers
1.Should usually be a nitrogen fixer.
2.Should be harmless for crops and human.
3.Should be capable to provide nutrients from soil to plants.
4.Should be able to multiply to compete with infectious microbes.
5.Should be able to survive in hostile env. in soil.
6.Should always be available for biofertilizer production.
7. Should increase crop yields.
Rhizobium, Azotobacter, Azospirillum, and blue-green algae (BGA)
are biofertilizers.

9. The carrier is a medium that can carry the microorganisms in sufficient
quantities and keep them viable under specified conditions in biofertilizer.
The most frequently used carrier for inoculant production is peat. A wide
range of substitutes e.g. lignite, coal, charcoal, bagasse, filter mud,
vermiculite, polyacrylamide, mineral soils, vegetable oils, etc. have been
tested as alternative carriers.

10. Quality control measures for
Inoculants
Like every product, the bio-fertilizers should also follow certain standards.
1. Inoculant should be carrier based or liquid based.
2. The carrier material should be in the form of powder, i.e. peat, lignite, peat soil, and humus,
etc.
3. The inoculant should contain minimum of 10₈ viable cells of bioinoculant/g of carrier on dry
weight basis when it is stored at 25–30°C.
4. The inoculant should have a maximum expiry period of 12 months from date of manufacture.
5. The pH of inoculant should be between 6.0 and 7.5.
6. Inoculant should be packed in 50–75 microns low-density polythene bags.
7. It should be free from any contaminant/contamination with other microorganisms.
8. Each packet containing the biofertilizer should be marked with the information’s e.g., name
of product, date of manufacture & expiry, net quantity and storage instructions.

11. Green Manuring
Two main methods of inoculation are currently being used (a) seed inoculation and (b) soil inoculation.
Green manuring is defined as a “farming practice where a green manure crop in the cropping system is
used for building soil organic matter and soil structure.”
Some of the cultivated legumes and annual legumes such as Crotolaria juncea, C. striata, Cassia
mimosoides, Cyamopsis pamas, Glycine wightii, Indigofera linifolia, Sesbania rostrata, Leucaena
leucocephala, etc. contribute nitrogen. These are green legume plants.
Functions:
1. They improve soil nutrients and protect soil erosion.
2. They fix nitrogen in soil, thus Less chemical fertilizers are required.
3. Minimize the pathogenic organisms in soil
4. Green manures provide forage for pollinating insects.
5. Cause reclamation of “usar lands”.

12. Role of cyanobacteria as
biofertilizer
,

13. Role of cyanobacteria as
biofertilizer
A mixture of 5 or 6 regionally acclimatized strains of cyanobacteria e.g. species of
Anabaena, Aulosira, Cylindrospermum, Gloeotrichia, Nostoc, Plectonema, Tolypothrix
etc. are generally used as starter inoculum.

14. Mass Cultivation of Azolla

15. Mass Cultivation of Azolla
The aquatic heterosporus fern contains endophytic
cyanobacterium, Anabaena azollae in its leaf cavity.
There are number of species of Azolla, namely A.
caroliniana, A, filiculoides, A. maxicana, A.
nilotica, A. pinnata and A. rubra which are used as
biofertilizer especially for paddy.
There are two methods for its application in field:
(a) Incorporation of Azolla in soil prior to rice
cultivation, and
(b) Transplantation of rice followed by water
draining and incorporation of Azolla.
Azolla mat is harvested and dried to use as green
manure.

16. Endophytic Nitrogen Fixers
The term endophyte refers to the microorganisms (bacteria and fungi) that colonize root
interior of plants and live most of their life inside the plant tissue. Examples are
Fusarium oxysporum, Bradyrhizobium japonicum, Fusarium culmorum & Fusarium
venenatum etc.
(i) Facultative Endophytic Diazotrophs:
Azospirillum spp., A. lipoferum & A. brasilense.
(ii) Obligate Endophytic Diazotrophs:
• Acetobacter diazotrophicus (syn. Gluconacetobacter diazotrophicus)-a nitrogen fixing
bacterium, alpha sub-class of the proteobacteria.
• Azoarcus spp., Herbaspirillum spp. and a partially identified Burkholderia sp.-beta sub-
class of the proteobacteria.
(iii) Other Bacteria:
1. Alcaligens-isolated from the rhizosphere of wet rice land.
2. Burkholderia-have potential as rice inoculant.

17. Isolation and Identification of
Endophytes
Sample plant
In petri plates with
selected media

18. Bio-Fertilizers aiding Phosphorus
Nutrition
There are some fungi such as Aspergillus awamori, Penicillium digitatum,
etc. and bacteria like Bacillus polymyxa, Pseudomonas striata, etc. that
solubilize unavailable form of P to available form.
Vesicular-arbuscular mycorrhizal (VAM) fungi colonize roots of
several crop plants. These are obligate symbionts and cannot be
cultured on synthetic media. They help plant growth through
improved phosphorus nutrition and protect the roots against
pathogens.

19. Ectomycorrhizal Fungi
Ectomycorrhizal Fungi:
In this case,
1. The basidiospores, chopped sporocarps, sclerotia, pure mycelial culture,
fragmented mycorrhizal roots or soil from mycorhizosphere region can
be used as inoculum.
2. The inoculum is mixed with nursery soil and seeds are sown thereafter.

20. The host plants which support large scale
production of inoculum are sudan grass,
strawberry, sorghum, maize, onion, citrus, etc.
There are two methods of using the inoculum:
(a) Using a dried spore-root-soil to plants by
placing the inoculum several centimeters below
the seeds or seedlings
(b) Using a mixture of soil- roots, and spores in
soil pellets and spores are adhered to seed
surface with adhesive.
The starter inoculum of VAM can be isolated
from soil by wet sieving and decantation
technique
VA Mycorrhizal Fungi

21. Disadvantages of bio & chemical
fertilizers
The disadvantages of biofertilizers
1. Biofertilizers provide lower nutrient density than chemical fertilizers, so more product is often required for the same effect
2. Biofertilizer production requires specific machinery
3. Biofertilizers can be difficult to store and may have a much shorter shelf-life than chemical fertilizers
4. Biofertilizers are often plant specific; what works on one crop does not work on another
5. Biofertilizers can have a strong, distinctive odor.
Disadvantages of chemical fertilizers
1. They are expensive.
2. Chemical fertilizers can deplete the soil.
3. They pollute the environment.
4. Chemical fertilizers interrupt soil ecology.
5. Their application can result in weak plants.
6. Contains limited nutrients.
7. Causes Over-fertilization or PH balance troubles.
8. They provide only short term benefits.

22. why we use nitrogen fixing microorganisms as
potential inoculate for Biofertilizer production
Nitrogen-fixing bacteria are prokaryotic microorganisms that are capable of transforming nitrogen gas finto “fixed
nitrogen” compounds, such as ammonia etc.
1. supply plants with the vital nutrient that they cannot obtain from the air themselves.
2. They usually do not allow pathogens to flourish.
3. protect the environment from pollutants since they are natural fertilizers.
4. Eco-friendly, more available and cost-effective.
5. capable of transforming atmospheric nitrogen into fixed nitrogen (inorganic compounds usable by plants).
6. play an important role in the nitrogen cycle.
7. They can form symbiotic relationships with members of all major plant groups.
8. When applied as green manure, it promotes soil fertility.
9. Crop waste can be utilised to help with weed control.
10. Nitrogen-fixing bacteria examples comprise Rhizobium (formerly Agrobacterium), Frankia, Azospirillum,
Azoarcus, Herbaspirillum, Cyanobacteria, Rhodobacter, Klebsiella, etc.
11. helps in fixing nitrogen in leguminous plants.
12. growth hormone production, phosphate solubilization, plant disease management and reclamation of better soil
health.
Species of Azotobacter, Bacillus, Clostridium, and Klebsiella etc.

23. why we use nitrogen fixing microorganisms as
potential inoculate for Biofertilizer production
Nitrogen-fixing bacteria.
Genus Rhizobium and
Bradyrhizobium.

24. Biofertilizers