▶ Biofertilizers are the substance that contains
microorganism's living or latent cells.
▶ Biofertilizers increases the nutrients of host
plants when applied to their seeds, plant surface
or soil by colonizing the rhizosphere of the plant.
▶ Biofertilizers are more cost-effective as compared
to chemical fertilizers
▶ ‘Bio’ means ‘life’. Therefore, by definition bio
fertilizers are living organisms that enrich the
nutrient quality of the soil.
▶ It refers to the use of microbes instead of
chemicals to enhance the nutrition of the soil.
As a result, it is also less harmful and does not
▶ This is what makes them so important to organic
farming because they are completely
friendly. Let’s take a look at the different microbes
are used as biofertilizers.
▶ Over the years, chemical fertilizers have helped
farmers increase crop production to meet the
increasing demand. However, the overuse of these
fertilizers is harmful because they cause air and
water pollution; and also deplete minerals from the
soil. Therefore, there is a need to now switch to
organic farming which involves the use of
▶ Bio-fertilizers are eco-friendly fertilizers, which are being
used to improve the quality and fertility of the soil.
▶ Bio-fertilizers are made from biological wastes and they do
not contain any chemicals. They are beneficial to the soil,
as they enrich the soil with micro-organisms that help in
producing organic nutrients, which in turn help the soil to
fight diseases. They therefore enrich the the nutrient
quality of the soil. They also restore the depleted nutrients
of the soil.
▶ The main sources of bio-fertilizers are bacteria, fungi and
cynobacteria (blue-green algae). Plants have a special
relationship with bacteria and fungi. They provide the plant
with nutrition, resistance against diseases and the ability to
combat worst climatic conditions.
▶The nitrogen-fixing nodules on the roots of legumes.
This a great example of biofertilizers. The nodules
are formed by the association of the bacterium
‘Rhizobium’ with the roots of these plants. This
association is beneficial and is, therefore, called
▶ Symbiotic associations exist between plants and
▶ These associations are called ‘Mycorrhizae’.
▶ The fungus in this association absorbs phosphorus
from the soil and provides it to the plant. Plants
that grow with these associations also show other
advantageous characteristics such as:
Tolerance to drought conditions and salinity.
Resistance to root-borne pathogens.
An overall increase in plant growth and
▶ These are blue-green bacteria found in water and on
▶ They also help fix atmospheric nitrogen. Examples are
Oscillatoria, Nostoc, Anabaena etc.
▶ The symbiotic association between the aquatic fern
Azolla and Anabaena is very important for rice fields.
▶ In this association, Anabaena receives carbon and
nitrogen from the plant in exchange for fixed nitrogen.
▶ This adds organic matter to the soil enhancing the
fertility of rice fields.
Phosphate solublizing bio fertilizer .
• Phosphorus is important for plant growth.
• In rhizosphere of crops will render insoluble soil phosphate
available to plants due to production and secretion of
organic acid by them.
• The use of this biofertilizer will also increase the
availability of phosphate from rock phosphate applied
directly even to neutral to alkaline soil or when used for
preparation of phosphor-compost.
Examples- Pseudomonas, bacillus, micrococcus
Preparation of Bio fertilizer
▶ Biocompost: It is a kind of organic fertilizer, which
is prepared from the waste of the sugar industry.
The waste is decomposed using a number of human
and plants friendly bacteria and Fungi.
Biocompost consists of nitrogen, phosphate
solubilizing bacteria and plenty of useful fungi like
the decomposing fungi. This biofertilizer helps the
farmers to increase soil fertility and thereby
increase the yield of the crops
Vermicompost: it organic fertilizer containing nitrogen
phosphorus, potassium, sulphur, organic carbon, sulfur,
hormones, enzymes, etc. If used over a period of time, the
soil becomes extremely fertile and all the lost nutrients
are restored back to the turf and the soil remains fertilizer
Rhizobium a bacterial, which induces nitrogen fixing
nodules on the roots of vegetables like peas, beans, etc.,
thereby, playing an important role in agriculture.
Azotobactor Nitrogen plays an extremely important
role in plant growth. Azotobactor improves the quantity of
atmospheric nitrogen in the soil and makes it available to
the plants. It also shields the roots from other pathogens
existing in the soil