What Is Bio Fertilizer 
 Ready to use live formulates of beneficial microorganisms which on application to seed, root or soil,
•  mobilize the availability of nutrients
•  help build up the micro-flora 
• Improve the soil health in general 
 The main sources of biofertilizers are bacteria, fungi, and cynobacteria 
 Why should we use biofertilizers? 
 modern agriculture is getting more and more dependent upon the steady supply of synthetic inputs. Thus, 
• Decrease in the quality of crop products
• spoil the soil properties, Osmatic pressure, pH, Conductivity and water holding capacity
• Affect adversly on population of micro-organisms and other parameters
 Types of Bio Fertilizer
 Nitrogen fixers 
 Convert nitrogen from the atmosphere into ammonium (NH4) or nitrate (NO3) ions which are readily useable by plants 
 These include Rhizobium, Azatobacter, Azospirillum, Blue Green Algae (BGA) and Azolla 
 secrete growth promoting substances 
 Contained in the root nodules or Free living
 Nitrogen fixers - Bacteria 
 Rhizobium
• Are soil bacteria that fix 
 nitrogen  after becoming 
 established inside root nodules 
 of legumes 
• They cannot independently fix nitrogen, and requires a plant host
• Morphologically they are generally gram negative, motile, non-sporulating rods
 Nitrogen fixers - Bacteria
 Azospirillum 
• Easy adaptability and limited host specificity
• Lives inside the cortical cells and xylem vessels of plant roots
• Have ability to fix 25-40 kg N/ha/year 
 Nitrogen fixers - Bacteria
 Azospirillum
• Secrete growth promoting substances like gibberellic acid and IAA which enhance root proliferation and growth of crop plants
 Nitrogen fixers – Blue Green
 Anabaena
• genus of filamentous cyanobacteria 
• they form symbiotic relationships with certain plants, such as the mosquito fern 
 Azolla
 They form a symbiotic relationship with the blue-green alga which fixes atmospheric nitrogen, giving the plant access to the essential nutrient 
 grow at great speed - doubling its biomass every two to three days
 30 – 100 kg N/ha/Year
 Yield increases 
 20 – 25 %  
 Phosphorous Solubilizing Bacteria
 Solubilize unavailable organic & inorganic forms of phosphorus (80%)
 Organic P slowly mineralized by the action of phosphatases
 Inorganic P solubilized by the action of organic and inorganic acids
 Belonging to the genera bacillus and pseudomonas 
 Phosphorous Solubilizing Bacteria
 Pseudomonas
• Gram-negative, 
 rod-shaped
• Produce amino acids and growth promoting substances 
• Produce About 30 kg P/ha/annum 
 Nutrients Up Take Enhancing Fungus
 Increase water uptake in plant
 Increase mineral uptake (especially P, Cu & Zn)
 Limits uptake of (Al, As, Ti, 
 Ba & Cd)
 Two types Ectomycorrhizae 
 and Endomycorrhizae 
 Nutrients Up Take Enhancing Fungus
 Ectomycorrhizae
• Form a sheath around the root
• Hyphae grow between the spaces in the cortical root cell 
• No cellular penetration by the hyphae
• Members of the 
 basidomycetes or the
 ascomycetes 
 Nutrients Up Take Enhancing Fungus
 Endomycorrhizae
• Hyphae form arbuscles (Bulb structure) 
• Called VAM (vesicular arbuscular mycorrhizae)
• Direct cell to cell 
 exchange of nutrients
• Hyphae grow into 
 intercellular spaces
 Sulphur Solubilizing Microbes
 Thiobacillus 
• They obtain nutrients by oxidizing iron and sulfur with O2 
 Sulphur Solubilizing Microbes
 Thiobacillus
• they require inorganic molecules as an electron donor and inorganic carbon (such as carbon dioxide) as a source
• They possess an iron oxidase, which allows them to metabolize metal ions
 Enzymatic Biofertilizer
 Microorganism having ability to secret enzymes and external enzymes
  which on application to seed, root or soil mobilize the availability of nutrients by their biological activity 
 Decomposers
 Break down organic waste and dead organisms.
 Releases key ions such as nitrates, and other minor nutrients that are not easily accessible for plants
 Many Kinds of Bacteria and Fungi assist in this process
 Potentials
 Cyanobacteria is an economically attractive and ecologically sound alternative to chemical fertilizers
 Specially in rice cultivation.
 benefits of using bio fertilizers 
 Increase crop yield by 20-30%
 Replace chemical nitrogen and phosphorus by 25%
 Stimulate plant growth
 benefits of using bio fertilizers
 Activate the soil biologically
 Restore natural soil fertility
 Provide protection against drought and some soil borne diseases
 Cost effective 
 Eco-friendly 
 How biofertilizers are applied to crops 
 Seed treatment 
• seeds are treated with nitrogenous biofertilizer and dried in shade. The treated seeds have to be sown as soon as possible 
 Seedling root dip 
• Recommended biofertilizers are mixed in this water and the roots of seedlings are dipped for 8-10 hrs 
 How biofertilizers are applied to crops
 Soil treatment 
• The recommended biofertilizers are mixed in  compost and kept overnight. This mixture is incorporated in the soil at the time of sowing or planting 
 Disadvantages of using Bio Fertilizers
 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
 Should use for the specified crop only. (Rhizobium)
 Disadvantages of using Bio Fertilizers
 Other chemicals should not be mixed with the biofertilizers
 Biofertilizers are live product and require care in the storage  
 Conclusion
 One of the major concerns in today's world is the pollution and contamination of soil
  The use of chemical fertilizers and pesticides has caused tremendous harm to the environment
  An answer to this is the biofertilizer, an environmentally friendly fertilizer now used in most countries