Biofertilizer for crop production and soil fertility

Abstract

Modern agriculture involves usage of pesticides and chemical fertilizers with an essence of increasing the world's food production. Thus, these serve as a fast food for plants, causing them to grow more rapidly and efficiently. Fertilizers, though they are vital as a nutrient supplement to plants and comprised mainly nitrogen (N), potassium (K) and phosphorous (P), they also cause several health hazard. Researchers have found "Bio fertilizer" as an excellent alternative to chemical fertilizers which provide nutrients through the action of nitrogen fixation, solubilising phosphorus, and trigger plant growth through the synthesis of growth promoting essence. The study reviews these continuously accessible and ecofriendly nutrients, types and their potential for crop production based on relevant literature and research work carried out by numerous researchers.

Full text

Academia Journal of Agricultural Research 6(8): 299-306, August 2018
DOI: 10.15413/ajar.2018.0130
ISSN: 2315-7739
©2018 Academia Publishing
Research Paper
Biofertilizer for crop production and soil fertility
Accepted 30th August, 2018
ABSTRACT
Modern agriculture involves usage of pesticides and chemical fertilizers with an
essence of increasing the world’s food production. Thus, these serve as a fast food
for plants, causing them to grow more rapidly and efficiently. Fertilizers, though
they are vital as a nutrient supplement to plants and comprised mainly nitrogen
(N), potassium (K) and phosphorous (P), they also cause several health hazard.
Researchers have found “Bio fertilizer” as an excellent alternative to chemical
fertilizers which provide nutrients through the action of nitrogen fixation,
solubilising phosphorus, and trigger plant growth through the synthesis of growth
promoting essence. The study reviews these continuously accessible and
ecofriendly nutrients, types and their potential for crop production based on
relevant literature and research work carried out by numerous researchers.
Key words: Nutrients, bio-fertilizer, types, crop production, benefits.
INTRODUCTION
Agriculture plays a pivotal role in the growth and survival
of nations; therefore, maintaining its quantity and quality
is essential for feeding the population and economic
exports. Over the years, agriculture has undergone various
scientific innovations in order to make it more efficient
(Ajmal, 2018). Modern agriculture involves usage of
pesticides and chemical fertilizers with an essence of
increasing the world’s food production, as these serve as a
fast food for plants causing them to grow more rapidly and
efficiently. Continuous application of chemical fertilization
leads to the decay of soil quality and fertility and might
lead to the collection of heavy metals in plant tissues,
affecting the fruit nutritional value and edibility (Farnia
and Hasanpoor, 2015).
Hence, in the recent years, many organic fertilizers have
been introduced that act as natural stimulators for plant
growth. A particular group of organic fertilizers includes
outcomes based on plant growth-promoting
microorganisms identified as ‘Biofertilizers’. These
biofertilizers comprised efficient strains of nitrogen fixing
or phosphate solubilizing microorganism. Organic farming
has appeared as a prime concern area globally in aspect of
the growing demand for safe and healthy food, durable
sustainability and issue on environmental pollution
associated with random use of agrochemicals (Ghany et al.,
2013).
Biological fertilization is based on the supply of organic
inputs including fertilizers, organic wastes, domestic
sewage, animal manure, and microorganisms, such as fungi
and bacteria. They are used to enhance fixation of
nutrients in the rhizosphere, produce plants of growth
stimulants, effective in soil stability, offer biological
control, biodegrade substances, recycle nutrients, support
mycorrhiza symbiosis, and evolve bioremediation
processes in soils contaminated with toxic, xenobiotic and
recalcitrant substances. The bio-fertilizers supply also
enhance the productivity per area in a comparatively short
time, consume smaller amounts of energy, reduce
contamination of soil and water, increase soil fertility, and
encourage antagonism and biological control of
phytopathogenic organisms.
Biofertilizers approach pose lots of such benefits from
an economic, social, and environmental point of view
(Carvajal-Muñoz and Carmona-Garcia, 2012).
Sneha S2, Anitha B2, Anjum Sahair R2, Raghu N1,
Gopenath T.S3, Chandrashekrappa GK4
and Kanthesh M Basalingappa1*
1Division of Molecular Biology, Faculty of Life
Sciences, JSS Academy of Higher Education and
Research (Deemed to be University), SS Nagara,
Mysuru-570015, India.
2Division of Biochemistry, Faculty of Life Sciences,
JSS Academy of Higher Education and Research
(Deemed to be University), SS Nagara, Mysuru-
570015, India.
3Division of Biotechnology, Faculty of Life
Sciences, JSS Academy of Higher Education and
Research (Deemed to be University), SS Nagara,
Mysuru-570015, India.
4Chairman, Faculty of Life Sciences, JSS Academy
of Higher Education and Research. (Deemed to be
University), SS Nagara, Mysuru-570015, India.
*Corresponding author. E-mail:
kantheshmb@jssuni.edu.in.

Academia Journal of Agricultural Research; Sneha et al. 300
Table 1: Major macro- and micro-nutrients and their role (Devi and Sumathy, 2017).
Element
Symbol
mg/kg
Soil percentage
Type
Application
Deficiency
Nitrogen
N
15,000
1.5
Macro
Leaf growth ;stem
Yellowish coloring of leaves;
short growth of the stalk.
Potassium
K
10,000
1.0
Macro
Stomata turgor; growth;
enzyme catalyst
stunt growth; leaf necrosis
(death); reduced gas
exchange.
Calcium
Ca
5,000
0.5
Macro
Acid/base regulation;
enzyme catalyst
Lack of growth on meristems;
blossom end rot disease.
Magnesium
Mg
2,000
0.2
Macro
ATP/ADP metabolism
activator; Photosynthesis;
respiration
Necrosis of lower grown-up
leaves
Phosphorous
P
2,000
0.2
Macro
Plant growth; fruit ripening
Lack of flowering ; plant
growth
Sulphur
S
1,000
0.1
Macro
Protein structure
Deplete growth in young
leaves; thin brittle stems.
Chlorine
Cl
100
-
Micro
Respiration, maintenance of
cell turgor
Wilt; stunt growth
Iron
Fe
100
-
Micro
Enzyme catalyst; chlorophyll
assembly; protein synthesis;
respiration
Necrosis of young leaves
Boron
B
20
-
Micro
Metabolism of calcium and
potassium
Lack of growth; blackening of
roots/shoots.
Manganese
Mn
50
-
Micro
Carbohydrate reduction
Necrotic spots on leave sp.;
leaf shed.
Zinc
Zn
20
-
Micro
Enzyme activator
Stunt growth
Copper
Cu
06
-
Micro
chlorophyll formation
Stunt growth; tip death; leaf
twisting; blue-green
coloration of leaves; necrosis,
loss of turgor
Molybdenum
Mo
0.1
-
Micro
nitrogen and Carbohydrate
metabolism
Interveinal necrosis;
mottling; marginal inward
folding of older leaves.
PLANT NUTRITION
Nutrition is a prerequisite required for the production of
crops and healthy food for the world’s enlarging
population. Plant nutrients are a key component of
sustainable agriculture. Soils carry natural reserves of
plant nutrients, but these reserves are unavailable to
plants with only a slight portion released each year
through biological activity or chemical processes. This
release is too lagging to repay for the removal of nutrients
by agricultural production and to meet crop requirement.
The 16 essential plant nutrients (N, P, K, Ca, Mg and S
(macronutrients), and Fe, Zn, Cu, Mo, Mn, B and Cl
(micronutrients)) in required quantities to achieve
maximum yield in crop production are well-established
(Table 1).

Academia Journal of Agricultural Research; Sneha et al. 301
Table 2: PGPR and their effect on crop yields (Abd El-Lattief, 2016).
Plant growth promoting Rhizobacteria
Crop Parameter
Rhizobium leguminosarum
Direct the growth promotion of canola and lettuce.
Pseudomonas putida
Early developments of canola seedlings, growth stimulation
in tomato plant.
Azospirillum brasilense and A. irakense
Growth of wheat and maize plants.
P. flurescens
Growth of pearl millet, enhance growth, leaf nutrient
contents and high yield of banana.
Azotobacter and Azospirillum spp.
Growth and productivity of canola.
P. alcaligenes, Bacillus polymyxa, and Mycobacterium
phlei
Improves the uptake of N, P and K by maize crop.
Pseudomonas, Azotobacter and Azospirillum spp.
Stimulates growth and increase the yield of chick pea.
R. leguminismarum and Pseudomonas spp.
Enhances the yield and phosphorus uptake in wheat.
P. putida, P. flurescens, A. brasilense and A.lipoferum
Enhances seed germination, seedling growth and yield of
maize.
P. putida, P. fluorescens, P. fluorescens, P. putida, A.
lipoferum, A. brasilense
Enhances seed germination, growth parameters of maize
seedling in green house and also gain yield on maize.
A fertile soil should possess all the macro and
micronutrients as these minerals promote plant nutrition.
Good fertility is basic for successful plant growth, and the
approach of fertilizes and manures is a necessary graining
activity. The maintenance of sufficient levels of nutrients in
soil is important for healthy plant growth (Devi and
Sumathy, 2017). Chemical fertilizers solitary do not
contribute all the nutrients in balanced quantities needed
by the plants. This result in reduction of soil organic
matter content, which in turn, affects the biological
activities and physical properties of the soil. All these
considerations in widespread have led to prompted
interest towards the utilization of biological manures. The
utilization of biological manure also helps to maintain crop
yields, but play a vital role towards exhibiting both direct
and indirect influence on the nutrient accessibility in soil
by boosting the physical, chemical and biological behavior
of soil and likewise enhances the utilization effectiveness
of applied fertilizers (Mercy et al., 2014). Increased crop
yield largely depend on the type of fertilizers used to
provide essential nutrients for plants. For optimal plant
growth, nutrients must be available in adequate and in
balanced quantities. From the soil nutrients, only a small
portion is released each year by biological activities or
chemical processes. Hence, fertilizers are designed to
supply the nutrients already present in the soil (Verma et
al., 2017).
BIOFERTILIZERS
From long-ago, the chemical pesticides and fertilizers have
played a vital role in improving agricultural production.
Although they have a short history in modern agriculture,
their instant action and low cost managed to bring them
quickly into the center of attention. Thus their adverse
effects on environment, plant, animal and human life have
diverted the priority on ecofriendly plant protection (Patel
et al., 2014). The term biofertilizer, depict everything from
manures to plant extract (Aggani, 2013).
Biofertilizer is a material which contains living
microorganisms. When applied to plant surfaces, they
promotes plant growth by increasing the supply of
primary nutrients to the host plant. Bio-fertilizers add
nutrients through natural processes such as nitrogen
fixation, solubilizing phosphorus, and stimulating plant
growth along with the synthesis of growth-promoting
substances. Bio-fertilizer is technically living; it can be
mutually beneficial in association with plant roots.
Involved microorganisms could easily convert complex
organic material into simpler compounds in order for
plants to easily absorb them. It retains the natural habitat

Academia Journal of Agricultural Research; Sneha et al. 302
bio-fertilizers are in use: Nitrogen fixing micro-organism; Phosphorus solubilising micro-
organism (Jehangir et al., 2017).
Fig .1: Biofertilizer types (Jehangir et al., 2017).
Plant growth promoting rhizobacteria (PGPR):
BIOFERTILIZER
Nitrogen fixing micro-organism
mm
Phosphorus solubilising micro-organism
Symbiotic
(Rhizobium,
Azolla)
Non-Symbiotic
(BGA, Azotobacter,
Azosprillum)
Non-Symbiotic
(Fungi, Bacteria)
Symbiotic
(VAM)
Figure 1: Biofertilizer types (Jehangir et al., 2017).
of the soil. Growth increases by 20-30%, substitute’s
chemical nitrogen and phosphorus by 25%, and enhances
the plant growth. It can impart protection adverse to
drought and some soil borne diseases. Biofertilizers are
ready to use live composition of beneficial
microorganisms, when it revised to seed, root or soil, it
induces the availability and utility of the microorganisms
and thus enhances the soil health (Bhattacharjee and Dey,
2014)
Chemical fertilizers alone does not provide all the
essential nutrients needed by the plants, resulting in
reduction of soil organic content and this in turn, adversely
affects the biological and physical characters of soil. All
these factors in general have led to increased interest
towards the utilization of organic manures. The practice of
organic manure does not only include the management of
crop yields, but also plays a vital role towards exhibiting
both direct, as well as indirect influence on the nutrient
accessibility in soil by improving the physical, chemical
and biological properties of soil and likewise enhances the
utilization effectiveness of applied fertilizers (Kapoor and
Pandit, 2015).
The rising importance of bio-fertilizers will reduce the
requirement of chemical fertilizers and the result it will be
helpful in the renewal of environment. Biofertilizer is an
organic by-product containing living microorganisms
arrested from plant roots or soil. Choice of bio-fertilizer is
becoming increasingly popular for the replacement of
chemical fertilizer in order to lower the cost of crop
production, enhance the growth and crop yield by
increasing the nitrogen availability and by producing
certain substances, such as auxin, cytokinin and
gibberellins, which are helpful in the growth of plants.
Microbial activity plays a key role in agriculture because
they are very significant in the movement and availability
of minerals required for plant growth and ultimately lower
the use of chemical fertilizers (Verma et al., 2017).
Bio-fertilizers containing useful micro-organisms
instead of synthetic chemicals are known to enhance plant
growth by the supply of plant nutrients and may help to
retain environmental health and soil productivity. Further,
the use of bio-fertilizers can raise productivity per unit
area in a short time, use smaller amounts of energy, reduce
contamination of soil and water, increase soil fertility, and
encourage antagonism and biological control of
phytopathogenic organisms (Yasin et al., 2012).
Biofertilizers are significant, not only for the decrease in
quantity of chemical fertilizers, but also for better yield in
sustainable agriculture.. Bio fertilizer production is cheap
and does not create pollution in the natural system (Farnia
and Hasanpoor, 2015). In India, systematic study on
biofertilizers was started by N. V. Joshi in 1920. Rhizobium
was the first isolated from various cultivated legumes, and
this was followed by vast research by Gangulee, Sarkaria
and Madhok on the physiology of the nodule bacteria
besides its inoculation for better crop production.
Rhizobium and Blue Green Algae (BGA) are considered as
the traditional biofertilizers, while Azolla, Azospirillum
and Azotobacter are at the middle stage (Rahimi et al.,
2014).
Biological nitrogen fixation
The recognition of nitrogen fixation was assigned by the
German scientists Hellriegel and Wilfarth in 1886, who
reported that legumes bearing root nodules could use
gaseous nitrogen. Soon after, in 1888, Beijerinck, a Dutch
microbiologist, succeeded in isolating a bacterial strain
from root nodules. This isolate was a Rhizobium
leguminosarum strain. Stewart (1969) stated that the
microbiologists Beijerinck in 1901 and Lipman in 1903
were responsible for isolation of Azotobacter spp., while
Winodgradsky (1901) isolated the first strain of
Clostridium pasteurianum. Innovation of nitrogen fixation
in blue-green algae was established later (Stewart, 1969).
At present, research efforts in these fields have showed
several beneficial characters (Barman et al., 2017).

Academia Journal of Agricultural Research; Sneha et al. 303
Nitrogen is the element of protein and nucleic acids and
chlorophyll. Therefore, nitrogen supply to the plant will
have impact on the amount of protein, amino acids,
protoplasm and chlorophyll formed. Hence, moderate
supply of nitrogen is vital to achieve high yield of crops.
Nitrogen makes up 78% of the atmospheric, but is present
in unavailable form for use by organism. In every one
hectare of land, there are ~80000 tones of remote
nitrogen. To convert it into available form, it needs to be
fixed either by industrial process or through Biological
Nitrogen Fixation (BNF). Lack of these nitrogen-fixers
make life on this planet difficult. Nitrogen (N) deficiency is
commonly a prime limiting factor for crops production. It
is a vital plant nutrient, widely applied as N-fertilizer to
enhance yield of agriculturally important crops. A
fascinating alternative to reduce the use of N-fertilizers
could be treatment of Plant Growth-Promoting bacteria
(Ghany et al., 2013).
Efficient ‘Nitrogen’ utilization is an essential goal in crop
management. Biofertilizers, the gift of modern agricultural
sciences, retard nitrification for acceptably longer time and
enhance soil fertility. Biofertilizers are essential
components of integrated nutrient management. Thus
would play vital role in productivity and sustainability of
soil, while protecting environment, being profitable,
environmental friendly and replaceable source of plant
nutrients to supplement chemical fertilizers in sustainable
agricultural system. Unlike inorganic fertilizers, bio-
fertilizers do not supply nutrients directly to plants. These
are the microbial inoculants containing the living cells of
effective strains used for approach to seeds, soil or
composting areas with the purpose to encourage the
microbial process to increase the availability of nutrients
that can easily be absorb by plants, capture the interior of
the plant and encourage growth by converting
nutritionally essential elements to convenient form
through biological process such as nitrogen fixation and
solubilisation of phosphate. Advantageous micro
organisms in biofertilizers help plants to grow and save
the plants from pest and diseases. Biofertilizers are raised
to harvest the naturally available, organic system of
nutrient mobilization (Jnawali, 2015).Today, two common
types of bio-fertilizers are in use: Nitrogen fixing micro-
organism and Phosphorus solubilising micro-organism
(Jehangir et al., 2017).
Plant growth promoting rhizobacteria (PGPR)
Differential bacterial genera are key components of soil.
The word Plant Growth Promoting Rhizobacteria was first
explained by Kloepper and Schroth in 1978 (Ghumare et
al., 2014). Plant growth promoting rhizobacteria have a
ability to fix atmospheric nitrogen and the production of
certain metabolites including auxin, cytokinin, gibberellins,
hydrogen cyanide (HCN), phytohormones and production
of certain unstable substances. PGPR also produces certain
mineral dissolving compounds, such as solublization of
phosphorus, and produce internal resistances. Azotobacter
has the ability to produce substances, such as Indole acetic
acid (IAA), Gibberellins, vitamin B complex and growth
promoting hormones which have great potential in
increasing plant growth and development and obtain high
crop yield. Marked increases in plant growth have been
observed by the application of Nitrogen fixing bacteria in
non-legume crops. Increase in plant growth might be due
to the biological nitrogen fixation and by the production of
growth promoting substances such as IAA and Gibberellic
acid. The bacteria which promote plant growth are known
as plant growth promoting rhizobacteria (Satyaprakash et
al., 2017).
Rhizobium
Rhizobium belongs to family the Rhizobiaceae. They are
Gram-negative, motile, non-sporulating rod shape, free
living organism present in soil and have the tendency to fix
the atmospheric N in symbiotic manner. They are known
as an endosymbiotic N fixing microorganism related with
root of legumes. It penetrates into plants through the root
system and later forms nodule. The fixation of N in root
nodules reacts with the available H molecules present and
then forms NH3 for which the energy required is gained
from the host. The carbohydrates produced by legume
plants are transfer to the nodules and are used by
Rhizobium as the only source of hydrogen in the
conversion of N to ammonia. The root nodules thus act as a
micro fermentor for organic N fixation where they can
convert atmospheric N into ammonia. Rhizobium is able to
influence the shoot and root growth in rice plants. Its
interaction with legume host is quite specific and it will fix
N in the particular host plant.
Furthermore, Rhizobium shows host specificity and it
was moderated by plant compounds such as flavonoids
which are produced by host plants. Flavonoid initiates the
nod genes present in Rhizobium. It begins infection in root
surface, after which root begins curling. After infection,
Rhizobium starts to move into the root hair. Thus after
certain level, the bacteria stops its multiplication and form
bacteroids which fix N nod and nif genes code for protein
called nodulin. It includes leg hemoglobin which is used for
nodule development and nif genes which are responsible
for N fixation. It is present in both free living and symbiotic
N fixing bacteria and includes structural genes for
nitrogenase and other regulatory enzymes. There are
several methods available for the introduction of
Rhizobium inoculants in soil; seed dipping is one of the
common method for the application of Rhizobium. During
seed germination, the bacteria infects into root hair and
spread towards the root. When the plant grows, Rhizobium
will convert N into ammonia for plant growth (Yasin,

Academia Journal of Agricultural Research; Sneha et al. 304
2012).
Cyanobacteria
Cyanobacteria are essential for global nitrogen cycle. N -
fixing cyanobacteria are between the most widespread and
important N fixers on Earth. Cyanobacteria / Blue Green
Algae are a various group of prokaryotes that generally
form complex associations with bacteria and green algae in
structures known as cyanobacterial mats. These are the
main N fixers in freshwater and marine systems. In large
areas of the world’s oceans, nitrogen –fixing
microorganisms provide a vital source of nitrogen to the
marine ecosystem. They also grow and fix nitrogen in
many terrestrial environments, from rainforests to
deserts. Cyanobacteria are able to survive in severe
environments because of rare adaptations such as their
ability to fix nitrogen and their resistance to desiccation.
Due to the potential to fix atmospheric nitrogen,
cyanobacterial mats have been used as biofertilizer in
current agriculture (kumar and Rao, 2012).
Azotobacter
Azatobacter are free living bacteria which grows well on a
nitrogen free medium. Such bacteria utilize the
atmospheric nitrogen gas for their cell protein synthesis.
This cell protein is later mineralized in soil after the death
of Azotobacter cells, thus contributing to the nitrogen
availability of the crop plants. Azotobacter spp. are
sensitive to acidic pH, high salts, and temperature of 35C.
Besides N2 fixation, Azotobacter synthesizes and secretes
large amounts of organically active substances, such as B
vitamins, nicotinic acid, pantothenic acid, biotin,
heteroxins, and gibberellins etc., which improve the root
growth of plants. Other characteristic of Azotobacter
associate dwith crop improvement is the secretion of
ammonia in the rhizosphere in the presence of root
exudates, which helps in modification of nutrient uptake
by the plants. Improvement in crop production due to
Azotobacter inoculation has been reported in a number of
crops. Azotobacter increases the production of the
agriculture crop plants by 10-12%. Azotobacter can also
improve growth and grain yield in wheat crop.
Azotobacter act as one of vital biofertilizer for rice and
other cereals, it can be applied by seed dipping and
seedling root dipping methods (Sridhar, 2012).
Azospirillum
Azospirillum is a Gram negative motile bacteria belonging
to the order Rhodospirillales, related with roots of
monocots, including essential crops, particularly wheat,
corn and rice. It is the main productive phytostimulator
inoculant for cereals worldwide. Azospirillum can be
established as an associative symbiosis with cereals, but
unlike mutualistic symbiosis, the association is not shown
by the formation of new organs. Azospirillum benefits the
plant directly, through associative nitrogen fixation,
synthesis of phytohormones (indole-3-acetic acid, IAA),
and regulation of plant hormonal balance by deamination
of the ethylene precursor. It is an associative type of
microorganism effective in colonizing the root surface of
the plants. By establishing a symbiotic organization, it
helps the plants to obtain nitrogen from the atmosphere
(Abd El-Lattief, 2016).
Vesicular Arbuscular Mycorrhiza (VAM)
Mycorrhizae are common beneficial relationships between
fungi and plant roots. VAM fungi contaminate and spread
inside the root. They have special structures known as
vesicles and arbuscules. The plant roots transfer
substances to the fungi, and the fungi aid in transferring
nutrients and water to the plant roots. The fungal hyphae
may increase the root lengths to 100-fold. The hyphae
reach further and wetter soil areas and help plants absorb
many nutrients, especially the less available mineral
nutrients such as phosphorus, zinc, molybdenum and
copper. Several VAM fungi form a kind of sheath around
the root, sometimes giving it a hairy, cottony appearance.
Because they provide a protective cover, mycorrhizae
improve seedling tolerance to drought, high temperatures,
infection by disease fungi and even to extreme soil acidity.
Application of VAM produces preferable root systems
which engage root rotting and soil borne pathogens. The
considerable growth response to mycorrhizal fungi is
likely seen in plants in highly weathered tropical acid soils
that are low in basic cations and P, and may have toxic
levels of aluminium. Plants with limited root systems
would be the most beneficial (Abd El-Lattief, 2016).
The function of biofertilizers in crop production
Soil micro-organisms play an important role in regulating
the dynamics of organic matter decomposition and the
availableness of plant nutrients such as N, P and S. It is
well-recognized that microbial inoculants constitute an
essential component of integrated nutrient management
that leads to sensible agriculture. Additionally, microbial
inoculants can be used as an economic input to enhance
crop productivity, the dosage of fertilizers can be lowered
and more nutrients can be harvested from the soil.
Biofertilizer could be used as nutrient source for soil
microbiology by maintaining fruit yield and quality and
promoting nutritionally supplied plants with lower
production costs. Nitrogen fixing microorganisms plays an

Academia Journal of Agricultural Research; Sneha et al. 305
vital role in improving yield by converting atmospheric
nitrogen into organic forms which are usable by plant.
Rhizobia are mutually associated with legumes and
nitrogen fixation occurs within the root or stem nodules
where the bacterium is located. Rhizobium inoculation
helps to enhance root nodulation, plant growth and
produces higher grain yield by 10-15% under cultivated
condition than a crop that has not been inoculated.
Nitrogen fixation by unique annual legumes has been
reported to vary from 35-270 kg/ha in a year.
The probable candidates for biological N fixation in rice
are species of Alcaligenes, Azospirillum, Bacillus, Herba
spirillum, Klebsiella, Pseudomonas and Rhizobium. Being
resistant to unusual temperature ranges, Rhizobium
generally enters the root hairs, multiplies and forms root
nodules. Bio fertilizers are mainly constituted of selected
living cells of microbes which provide the plants with
nutrients through their root system. The microbes in these
fertilizers use different mechanisms to supply nutrients to
the plants. They are capable of nitrogen fixation,
phosphate solubilization, phosphate mobilization, and
promotion of rhizobacteria. The preparation includes
selective microorganism that may be useful for the soil.
The suitability of the packaging is ensured for a longer
shelf life and the safety of the environment and the user.
The use of bio fertilizers is becoming popular because of
their nutritious value and relatively lowers environmental
impacts. They are also offer as a renewable resource which
can be actively used in place of chemical fertilizers. As
reported by numerous researchers, the incorporation of
bio-fertilizers plays a key role in enhancing soil fertility,
crop yield and final yield. Addionally, their application in
soil enhances soil biota and minimizes the use of chemical
fertilizers (Mishra et al., 2012). Biofertilizers stimulate
nutrients that favor the development of biological
activities in soils which help in maintaining plant health.
This is enhanced by the addition of balanced nutrient,
which provide food and growth of microorganisms, and
also beneficial soil worms are required. As an outcome of
good structure provided to the soil, root growth and
organic matter in soil are enhanced. Micorrhizal
development is greatly influenced by the application of
biofertilizers, which in turn, is responsible for the
availability of high phosphorus content in the soil.
CONCLUSION
In current agriculture practices, chemical fertilizers have
reduced the fertility of soil, making it unsuited for raising
crop plants. Additionally, the excessive use of these inputs
has also led to severe health and environmental hazards
such as soil erosion, water contamination, pesticide
poisoning, falling ground water table, water logging and
depletion of biodiversity. Biofertilizers spontaneously
activates the microorganisms found in the soil in an
effective and eco-friendly way, thereby gaining more
importance for utilization in crop production, restoring the
soils fertility and protecting it against drought, soil
diseases and thus stimulate plant growth. Biofertilizers
lead to soil enrichment and are suitable with long-term
sustainability. Further, they pose no danger to the
environment and can be substituted with chemical
fertilizers. The application of bio-fertilizers can minimize
the use of chemical fertilizers, decreasing environmental
hazards, enhance soil structure and promote agriculture.
Biofertilizers are cheaper and remarkable in affecting the
yield of cereal crops. Bio-fertilizers being important
components of organic farming play a key role in
maintaining long term soil fertility and sustainability by
fixing insoluble P in the soil into forms available to plants,
thus increasing their effectiveness and availability. In
context of both the cost and environmental impact of
chemical fertilizers, excessive reliance on the chemical
fertilizers is not a useful strategy in the long run due to the
cost, both in domestic resources and foreign exchange;
participate in setting up of fertilizer plants and
maintaining the production. Biofertilizers are the
alternative sources to meet the nutrient requirement of
crops. In Biofertilizers, beneficial bacteria are Azotobacter,
Azospirillium, Rhizobium, Mycorrhizae which are very
essential in crop production. Biofertilizer can also make
plant resistant to unfavorable environmental stresses.
REFERENCES
Abd El-Lattief EA (2016).Use of azospirillum and azobacter bacteria as
biofertilizers in cereal crops: A review. Int. J. Res. Eng. Appl. Sci. 6(7): 36-
44.
Aggani SL (2013). Development of bio-fertilizers and its future
perspective. Schol. Acad. J. Pharm. 2(4): 327-332.
Ajmal M et al (2018). Biofertilizer as an Alternative for Chemical
Fertilizers. J. Agri. Sci. 7(1): 1-7.
Barman M et al (2017). Biofertilizer as Prospective Input for Sustainable
Agriculture in India. Int. J. Curr. Microbiol. App. Sci. 6 (11): 1177-1186.
Bhattacharjee R, Dey U (2014).Biofertilizer, a way towards organic
agriculture: A Review. Afr. J. Microbiol. Res. 8(24): 2332-2343.
Carvajal-Muñoz JS, Carmona-Garcia CE (2012). Benefits and limitations of
biofertilization in agricultural practices. Livestock Research for Rural
Development. 24(3).
Devi V, Sumathy VJH (2017). Production of biofertilizer from fruit wastes.
Eur. J. Pharm. Med. Res. 4(9): 436-443.
Farnia A, Hasanpoor K (2015).Comparison between effect of chemical
and biological fertilizers on yield and yield components in wheat
(Triticum aestivum L.). Indian J. Nat. Sci. 5 (30): 7792-7800.
Ghany TMA et al (2013). Role of biofertilizers in agriculture: a brief
review. Mycopath. 11 (2): 95-101.
Ghumare V et al (2014). Bio-fertilizers- increasing soil fertility and crop
productivity, Jr. Ind. Poll. Cont. 30(2): 196-201.
Jehangir IA, et al (2017). Biofertilizers an approach to sustainability in
agriculture: A review. Int. J. Pure Appl. Biosci. 5(5): 327-334.
Jnawali AD, et al (2015). Role of azotobacter in soil fertility and
sustainability–a review. Adv. Plants Agric. Res. 2(6): 1-5.
Kapoor A, et al (2015).Organic agriculture: biofertilizer - A review. Int. J.
Pharmaceut. Biol. Arch. 6 (5): 1-5.
Kumar SRS, Rao KVB (2012). Biological nitrogen fixation: A review. Int. J.
Adv. Life Sci.1: 1-6.
Mercy S, et al (2014). Application of different fruit peels formulations as a

Academia Journal of Agricultural Research; Sneha et al. 306
natural fertilizer for plant growth. Int. J. Sci. Techno. Res. 3(1): 300-
307.
Mishra DJ, et al (2012). Role of bio-fertilizer in organic agriculture: A
review. Res. J. Recent. Sci. 2: 39-41.
Patel N (2014). Bio fertilizer: A promising tool for sustainable farming.
Int. J. Innov. Res. Sci. Eng. Techno. 3 (9): 15838-15842.
Rahimi S (2014).Classification of bio-fertilizers and regulations and
international standards in the field of agricultural production and
healthy eating: Review Article. J. Appl. Sci. Agri. 9(1): 1120-1122.
Satyaprakash M (2017). Phosphorous and phosphate solubilising bacteria
and their role in plant nutrition. Int. J. Curr. Microbiol. Appl. Sci. 6 (4):
2133-2144.
Shridhar BS (2012). Review: Nitrogen fixing microorganisms. Int. J.
Microbiol. Res. 3(1): 46-52.
Verma S (2017). Bio-efficacy of organic formulations on crop production-
A review. Int. J. Curr. Microbiol. App. Sci. 6(5): 648-665.
Yasin M (2012). Bio-fertilizers, substitution of synthetic fertilizers in
cereals for leveraging agriculture. Crop Environ. 3 (1-2): 62-66.
Yasin M (2012).Review article: bio-fertilizers, substitution of synthetic
fertilizers in cereals for leveraging agriculture. Crop Environ. 3 (1-2):
62-66.
Cite this article as:
Sneha S, Anitha B, Sahair RA, Raghu N, Gopenath TS,
Chandrashekrappa GK, Basalingappa KM (2018). Biofertilizer for
crop production and soil fertility. Acad. J. Agric. Res. 6(8): 299-306.
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