What is biofertilizer?

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After the introduction of chemical fertilizers in the last century, farmers were happy of getting increased yield in agriculture in the beginning. But slowly chemical fertilizers started displaying their ill-effects such as leaching out, and polluting water basins, destroying micro-organisms and friendly insects, making the crop more susceptible to the attack of diseases, reducing the soil fertility and thus causing irreparable damage to the overall system.

A number of intellectuals throughout the world started working on the alternatives and found that biofertilizers can help in increasing the yield without causing the damage associated with chemical fertilizers.
Bio fertilizers are
• microbial products containing living cells of different types of micro organisms
• possess the innate ability either to fix or mobilize important nutrient elements from non-usable forms through biological process.
• needed to be applied to soil to enhance microbial activity in the rhizosphere
• playing a significant role in intigrated plant nutrient systems (IPNS)

Different companies producing Biofertilizers are:
• Niftal
• Liphatech
• Zamseed
• Indene
Why should we use bio fertilizers?
With the introduction of green revolution technologies the modern agriculture is getting more and more dependent upon the steady supply of synthetic inputs (mainly fertilizers), which are products of fossil fuel (coal+ petroleum). Adverse effects are being noticed due to the excessive and imbalanced use of these synthetic inputs. This situation has lead to identifying harmless inputs like bio fertilizers. Use of such natural products like bio fertilizers in crop cultivation will help in safeguarding the soil health and also the quality of crop products.
What types of bio fertilizers are available?
For Nitrogen
Rhizobium for legume crops.
Azotobacter/Azospirillum for non legume crops.
Acetobacter for sugarcane only.
Blue –Green Algae (BGA) and Azolla for low land paddy.
For Phosphorous
Phosphatika for all crops to be applied with Rhizobium, Azotobacter, Azospirillum and Acetobacte
Galaxy of Biofertilizers
Phospho: It releases insoluble phosphorus in soil and fix this phosphorus in clay minerals which is of great significance in agriculture.

Rhizo: Rhizo Bacterial plays a very important role in agriculture by inducing nitrogen fixings nodules on the root of legumes such as peas,beans clove and alfalfa.

Azotobactor: Atmosphere contains 78% nitrogen which is a very important nutrient for plant growth. Azotobactor fixes the atmospheric nitrogen in the soil and make it available to the plants. It protects the roots from other pathogens present in the soil.

The Outlines of Commercial Manufacture of Bio-fertilizers :

The manufacturing process in short involves :
Selection of suitable strain of the organism for which market demand is identified.
Mass multiplication.
Mixing of the culture with carrier material and packing.

The steps involved are as follows :

Culture selection and maintenance:

The pure mother cultures of various strains are being maintained in Agricultural Universities, IARI, some ICAR institutions, Regional biofertilizer labs of MOA, etc. There are international sources of supply also like NifTAL, IRRI etc. The mother culture in test tubes of desired strain can be purchased from the identified sources. They have to be further sub-cultured and maintained purely for mass production by adopting standard techniques under the supervision of trained microbiologist.

Culture augmentation:

In the next stage the culture has to be mass multiplied in two levels namely (i) at primary level using shakers in flasks and (ii) Secondary stage multiplication in fermenters. The important factor in this is the preparation of growing medium in which the culture is mass multiplied. There are standard media on which information is available from published sources like Norris & date, Fred et al, ISI approved etc. in case of Rhizobium. Similarly composition for growth media are available for other cultures. After the media is formulated and sterilized in fermenter, it is inoculated using the shorter cultures multiplied in the flasks at definite ratios usually 5%. The bacteria growing medium is called broth and it is continuously aerated by passing sterile air from compressors. After about 3-4 days fermentation period, the broth will be ready for packing in a carrier material. At various stages the quality is tested by drawing samples.


Carrier sterilization:

While the broth is getting ready in the fermenter the carrier material, which is usually the carbon source for the cultures to survive, is sterilized in autoclaves and kept ready for mixing the broth. Peat imported from countries like U.S., Australia is reported to be the best source of carrier material. However, as it is costly lignite is used extensively in India. The carrier is either sterilized in bulk or it is packed and then the packets are sterilized.


Mixing and packing:

There are 2-3 alternatives depends upon the sophistication and automation of the unit.

Under non sterile system, the broth is harvested from the fermenter into sterilized carrier - the mixing is done manually under aseptic condition and packed in polythene bags of desired quantity.
In a slightly upgraded method, the broth and sterilized carrier are mixed mechanically in a blender and the material is packed using semiautomatic packing and sealing machine. In a slightly modified method some units are packing by delivering desired quantities of carrier and broth simultaneously from separate pipe conveyance system in to the polythene bags.
Under a completely sterile system the carrier is taken in autoclavable polypropylene bags and pre sealed - into which the broth from fermenter is directly injected with the help of dispenser. The injection hole is immediately sealed. The packets are kept in incubation room for about a week before transferring to store room.

Sterile system of packing using auto syringe and dispenser is recommended to be the best method and all new units should follow and adopt this system.






Equipment needed:

List of equipment Name Approximate Purpose quantity needed

1. Boiler/steam generator 1 big or 2 small To generate steam for sterilization

2. Autoclaves - Horizontal 1 For carrier sterilization

Vertical 2-4 For smaller quantities and small containers.

3. Rotary shakers (2 tier) 2 Culture growth

4. Fermenters 2 for culture fermentation (500 lit capacity)

5. Laminar air flow - work station of 6' size 2 for inoculation purposes

6. BOD incubator 1 for culture growth sterilization

7. Hot air oven 2 for dry glassware

8. Air conditioner 3-4

9. Refrigerator 2

10. Microscope 1

11. Balances 2-3

12. Dispensers or

Semi automatic mixing 2 sets with automatic injection systems

13. Sealing machine 1

14. Lab equipments: For quality control and microbial works

pH meter 1

Colony counter 1

Microscope 1

Fridge 1

15. Glassware As needed. Conical flasks are the major requirement

16. Distiller water unit or 1 set

Demineralization unit

17. Office furniture As needed


Layout of the production unit:

The biofertilizer plant should be housed in a suitable building complex. The main production unit should have separate channels for bacteriological work, carrier making and mixing and customer and visitor/marketing way. In addition there should be rooms with separate entrance for utilities like power, steam generator and stores. Appropriate design can be adopted in consultation with scientists/engineers.


Raw material:

The chief raw materials needed for the production of biofertilizers are as follows

Mother cultures
Carrier material - lignite or bentonite or peat of desired quality in powder form (70-100 mesh)
Polythene bags, HDPE bags, cardboard cortans
Growth materials - include Manital, sucrose and chemical nutrients.




How could one get good response to biofertilizer application?
• Biofertilizer product must contain good effective strain in appropriate population and should be free from contaminating microorganisms.
• Select right combination of biofertilizers and use before expiry date.
• Use 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 the supply of phosphorus and other nutrients.



What precautions one should take for using biofertilizers?
• Biofertilizer packets need to be stored in 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 for the specified crop only.
• Other chemicals should not be mixed with the biofertilizers.
• Biofertilizers are live product and require care in the storage
• Both nitrogenous and phosphatic biofertilizers are to be used to get the best results.
Advantages of Biofertilizers
1. harnesses atmospheric nitrogen and makes it available directly to the plants.
2. increases phosphorus uptake by solubilising and releasing unavailable phosphorus.
3. enhances root proliferation due to release of growth promoting harmones.
4. increases the crop yields by 10 – 25 %.
5. improves soil properties and sustain soil fertility.
6. are cost effective and environment friendly.
7. benefit to cost ratio of biofertilizers is fairly high.