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Thursday, September 11, 2008


What Is Bio Fertilizer
. Ready to use live formulates of such beneficial microorganisms which on application to seed, root or soil mobilize the availability of nutrients by their biological activity in particular, and help build up the micro-flora and improve the soil health in general
Why should 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
. 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
¨genus of gamma proteobacteria
¨Gram-negative, rod-shaped and polar-flagella bacteria
¨Known to produce amino acids and growth promoting substances which help in better growth of plants
¨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
¨colorless, rod-shaped, Gram-negative bacteria with polar flagella
¨They possess an iron oxidase, which allows them to metabolize metal ions
Sulphur Solubilizing Microbes
. Thiobacillus
¨ they require inorganic molecules as an electron donor and inorganic carbon (such as carbon dioxide) as a source.
¨ They obtain nutrients by oxidizing iron and sulfur with O2

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
. Break down organic waste and dead organisms.
. Releases key ions such as nitrates, phosphates and sulfates for use by other organisms
. Many Kinds of Bacteria and Fungi assist in this process
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.
. As Rhizobium is crop specific, one should use for the specified crop only.
Disadvantages of using Bio Fertilizers
. Other chemicals should not be mixed with the biofertilizers
. Biofertilizers are live product and require care in the storage

. Biofertilizers will help solve such problems as increased salinity of the soil and chemical run-offs from the agricultural fields
. Thus, biofertilizers are important if we are to ensure a healthy future for the generations to come

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