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'Biofertilizer' is a substance which contains living microorganisms which, when applied to seed, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant.[1] Biofertilizers add nutrients through the natural processes of Nitrogen fixation , solubilizing phosphorus, and stimulating plant growth through the synthesis of growth promoting substances. Biofertilizers can be expected to reduce the use of chemical fertilizers and pesticides. The microorganisms in biofertilizers restore the soil's natural nutrient cycle and build soil organic matter. Through the use of biofertilizers, healthy plants can be grown while enhancing the sustainability and the health of soil. Since they play several roles, a preferred scientific term for such beneficial bacteria is plant-growth promoting rhizobacteria (PGPR). Therefore, they are extremely advantageous in enriching the soil fertility and fulfilling the plant nutrient requirements by supplying the organic nutrients through microorganism and their byproduct. Hence, biofertilizers do not contain any chemicals which are harmful to the living soil. Biofertilizers are Eco-friendly organic agro-input and more cost effective than chemical fertilizers. Biofertilizers like Rhizobium, Azotobacter, Azospirillum and blue green algae(BGA) are in use since long time ago. Rhizobiuminoculant is used for leguminous crops. Azotobacter can be used with crops like wheat, maize, mustard, cotton, potato and other vegetable crops. Azospirillum inoculants are recommended mainly for sorghum, millets, maize, sugarcane and wheat. Blue green algae belonging to genera Nostoc, Anabaena, Tolypothrix and Aulosira fix atmospheric nitrogen and are used as inoculants for paddy crop grown both under upland and low land conditions. Anabaena in association with water fern Azolla contributes nitrogen up to 60 kg/ha/season and also enriches soils with organic matter [2] Other types of bacteria, so-called phosphate solubilizing bacteria like Pantoea agglomerans strain P5, and Pseudomonas putida strain P13 [3] are able to solubilize the insoluble phosphate from organic and inorganic phosphate source [4] . In fact, due to immobilization of phosphate by mineral ions such as Fe, Al and Ca or organic acids, the rate of available phosphate (Pi) in soil is well below plant needs. In addition, chemical Pi fertilizer are also immobilized in the soil immediately so that less than 20 percent of added fertilizer is absorbed by plants. Therefore, reduction in Pi resources, on one hand, and environmental pollutions resulted from both production and applications of chemical Pi fertilizer, on the other hand, have already demanded the use of new generation of phosphate fertilizers globally known as phosphate solubilizing bacteria or phosphate biofertilizers,

Contents

[hide] 1 Benefits of using Biofertilizers 2 Advantages of Biofertilizers

3 References

o 3.1 External links

[edit] Benefits of using Biofertilizers

As it is living thing, it can symbiotically associate with plant root. Involved microorganisms could readily and safely convert complex organic material in simple compound, so that plant easily taken up. Microorganism function is in long duration causing improvement of the soil fertility. It maintains the natural habitat of the soil. It increases crop yield by 20-30%. Replace chemical nitrogen and phosphorus by 25% in addition to stimulating of the plant growth. Finally it can provide protection against drought and some soil borne diseases.

[edit] Advantages of Biofertilizers

Cost effective relative to chemical fertilizer and reduces the costs towards fertilizers use, especially regarding nitrogen and phosphorus. It is environmentally friendly fertilizer that not only prevents damaging the natural source but helps to some extend clean the nature from precipitated chemical fertilizer.

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Biofertilizers

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. Biofertilizers are organisms that enrich the nutrient quality of soil. The main sources of biofertilizers are bacteria, fungi, and cynobacteria (blue-green algae). The most  striking relationship that these have with plants is symbiosis, in which the partners derive benefits from each other.

Plants have a number of relationships with fungi, bacteria, and algae, the most common of which are with mycorrhiza, rhizobium, and cyanophyceae. These are known to deliver a number of benefits including plant nutrition, disease resistance, and tolerance to adverse soil and climatic conditions. These techniques have proved to be successful biofertilizers that form a health relationship with the roots. 

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.

Mycorrhiza

Mycorrhizae are a group of fungi that include a number of types based on the different structures formed inside or outside the root. These are specific fungi that match with a number of favourable parameters of the the host plant on which it grows. This includes soil type, the presence of particular chemicals in the soil types, and other conditions.

These fungi grow on the roots of these plants. In fact, seedlings that have mycorrhizal fungi growing on their roots survive better after transplantation and grow faster. The fungal symbiont gets shelter and food from the plant which, in turn, acquires an array of benefits such as better uptake of phosphorus, salinity and drought tolerance, maintenance of water balance, and overall increase in plant growth and development.

While selecting fungi, the right fungi have to be matched with the plant. There are specific fungi for vegetables, fodder crops, flowers, trees, etc.

Mycorrhizal fungi can increase the yield of a plot of land by 30%-40%. It can absorb phosphorus from the soil and pass it on to the plant. Mycorrhizal plants show higher tolerance to high soil temperatures, various soil- and root-borne pathogens, and heavy metal toxicity.

Legume-rhizobium relationship

Leguminous plants require high quantities of nitrogen compared to other plants. Nitrogen isan inert gas and its uptake is possible only in fixed form, which is facilitated by the rhizobiumbacteria present in the nodules of the root system. The bacterium lives in the soil to form rootnodules (i.e. outgrowth on roots) in plants such as beans, gram, groundnut, and soybean.

Blue-green algae

Blue-green algae are considered the simplest, living autotrophic plants, i.e. organisms capable of building up food materials from inorganic matter. They are microscopic. Blue-green algae are widely distributed in the aquatic environment. Some of them are responsible for water blooms in stagnant water. They adapt to extreme weather conditions and are found in snow and in hot springs, where the water is 85 °C.

Certain blue-green algae live intimately with other organisms in a symbiotic relationship. Some are associated with the fungi in form of lichens. The ability of blue-green algae tophotosynthesize food and fix atmospheric nitrogen accounts for their symbiotic associations and also for their presence in paddy fields.

Blue-green algae are of immense economic value as they add organic matter to the soil and increase soil fertility. Barren alkaline lands in India have been reclaimed and made productive by inducing the proper growth of certain blue-green algae.

The term biopesticide is used for microbial biological pest control agents that are applied in a similar manner to chemical pesticides. Commonly these are bacterial, but there are also examples of fungal control agents, including Trichoderma spp. and Ampelomyces quisqualis (a control agent for grape powdery mildew). Bacillus subtilis are used to control plant pathogens. Weeds and rodents have also been controlled with microbial agents.

One well-known insecticide example is Bacillus thuringiensis, a bacterial disease of Lepidoptera, Coleoptera and Diptera. Because it has little effect on other organisms, it is considered more environmentally friendly than synthetic pesticides. The toxin from Bacillus thuringiensis (Bt toxin) has been incorporated directly into plants through the use of genetic engineering.

Biological insecticides include products based on:

entomopathogenic fungi (e.g.Beauveria bassiana, Metarhizium anisopliae), entomopathogenic nematodes (e.g. Steinernema feltiae) and entomopathogenic viruses (e.g.. Cydia pomonella granulovirus ).

Biopesticides, key components of integrated pest management (IPM) programs, are receiving much practical attention as a means to reduce the load of synthetic chemical products being used to control plant diseases. In most cropping systems, biopesticides should not necessarily be viewed as wholesale replacements for chemical control of plant diseases, but rather as a growing category of efficacious supplements that can be used as rotation agents to retard the onset of resistance to chemical pesticides and improve sustainability. In organic cropping systems, biopesticides can represent valuable tools that further supplement the rich collection of cultural practices that ensure against crop loss to diseases.

Biopesticides for use against crop diseases have already established themselves on a variety of crops. For example, biopesticides already play an important role in controlling downy mildew diseases. Their benefits include: a 0-Day PreHarvest Interval, the ability to use under moderate to severe disease pressure, and the ability to use as a tank mix or in a rotational program with other registered fungicides. Because some market studies estimate that as much as 20% of global fungicide sales are directed at downy mildew diseases, the integration of biofungicides into grape production has substantial benefits in terms of extending the useful life of other fungicides, especially those in the reduced-risk category.

A major growth area for biopesticides is in the area of seed treatments and soil amendments. Fungicidal and biofungicidal seed treatments are used to control soil borne fungal pathogens that cause seed rots, damping-off, root rot and seedling blights. They can also be used to control internal seed–borne fungal pathogens as well as fungal pathogens that are on the surface of the seed. Many biofungicidal products also show

capacities to stimulate plant host defenses and other physiological processes that can make treated crops more resistant to a variety of biotic and abiotic stresses.

The Manual of Biocontrol Agents[1] gives a review of the available biological insecticide (and other biology-based control) products. In order to implement these environmentally-friendly pest control agents, it is often especially important to pay attention to their formulation [2] and application.[3]

[edit] Perceived Advantages of biopesticides

do not leave harmful residues substantially reduced impact on non-target species when locally produced, may be cheaper than chemical pesticides in the long-term may be more effective than chemical pesticides (e.g. as

demonstrated by the LUBILOSA Programme)

[edit] Perceived disadvantages

high specificity, which will require an exact identification of the pest/pathogen and may require multiple pesticides to be used

often slow speed of action (thus making them unsuitable if a pest outbreak is an immediate threat to a crop)

often variable efficacy due to the influences of various biotic and abiotic factors (since biopesticides are usually living organisms, which bring about pest/pathogen control by multiplying within the target insect pest/pathogen)

living organisms evolve and increase their resistance to biological, chemical, physical or any other form of control. Unless the target population is completely exterminated or is rendered incapable of reproduction, the surviving population will inevitably acquire a tolerance of whatever pressures are brought to bear - this results in an evolutionary arms race.

Biopesticides

Biopesticides are certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals. For example, canola oil and baking soda have pesticidal applications and are considered biopesticides. At the end of 2001, there were approximately 195 registered biopesticide active ingredients and 780 products. Biopesticides fall into three major classes:

(1) Microbial pesticides consist of a microorganism (e.g., a bacterium, fungus, virus or protozoan) as the active ingredient. Microbial pesticides can control many different kinds of pests, although each separate active ingredient is relatively specific for its target pest[s]. For example, there are fungi that control certain weeds, and other fungi that kill specific insects.

The most widely used microbial pesticides are subspecies and strains of Bacillus thuringiensis, or Bt. Each strain of this bacterium produces a different mix of proteins, and specifically kills one or a few related species of insect larvae. While some Bt's control moth larvae found on plants, other Bt's are specific for larvae of flies and mosquitoes. The target insect species are determined by whether the particular Bt produces a protein that can bind to a larval gut receptor, thereby causing the insect larvae to starve

(2) Plant-Incorporated-Protectants (PIPs) are pesticidal substances that plants produce from genetic material that has been added to the plant. For example, scientists can take the gene for the Bt pesticidal protein, and introduce the gene into the plant's own genetic material. Then the plant, instead of the Bt bacterium, manufactures the substance that destroys the pest. The protein and its genetic material, but not the plant itself, are regulated by EPA.

(3) Biochemical pesticides are naturally occurring substances that control pests by non-toxic mechanisms. Conventional pesticides, by contrast, are generally synthetic materials that directly kill or inactivate the pest. Biochemical pesticides include substances, such as insect sex pheromones, that interfere with mating, as well as various scented plant extracts that attract insect pests to traps. Because it is sometimes difficult to determine whether a substance meets the criteria for classification as a biochemical pesticide, EPA has established a special committee to make such decisions.

Types of BiopesticidesBy Ida Tolen, eHow Contributor updated: December 1, 2009

Types of Biopesticides

Biopesticides, or biological pesticides, are pest control agents obtained from natural substances, such as plants, minerals and bacteria. One advantage of using biopesticides over conventional pesticides is that they can be less toxic. The Environmental Protection Agency (EPA) requires the registration of all biopesticides and reviews these for any potential adverse effects on the environment or people.

The Facts

1. Whether derived from plants that are living organisms or substances like minerals, biopesticides can play an important role in protecting agriculture from certain unwanted pests. The active ingredients in these biological pesticides can also include the use of microbial organisms, genetic material or pheromones. According to the EPA, there were roughly 195 of these active ingredients registered by the end of 2001. Biopesticides function in a variety of ways to suppress pests. The three main types of biopesticides are plant-incorporated-protectants, biochemical and microbial pesticides.

Microbial Pesticides

2. Microbial pesticides contain active ingredients of specific types of microorganisms, such as a fungus, bacterium or protozoan. Each active ingredient can be utilized to target a specific type of pest. For example, some fungi can suppress certain weeds, while certain types of bacteria can control different species of insect larvae, such as mosquitoes, moths or flies. The most commonly utilized microbial pesticides come from strains of the bacteria called Bacillus thuringiensis (Bt). The bacteria strains manufacture different protein mixes that can target specific insect larvae and will not affect other organisms.

Biochemical Pesticides

3. Biochemical pesticides use natural substances like insect sex pheromones, which can disrupt mating, thus controlling the insect population. Other types of biochemical pesticides can include the use of hormones, enzymes and scented plant extracts to attract and trap certain pests. These are good alternatives to conventional pesticides because often the latter contain synthetic toxic material to destroy insects.

Plant-Incorporated-Protectants

4. By introducing genetic material into plants, scientists can make plants produce pesticidal substances which can target and kill specific pests. In some cases, the addition of a gene with a particular Bt protein can produce these plant incorporated protectants, or plant pesticides. In theses cases, EPA regulations apply only to the protein, genetic substance and not the plant.

Benefits and Advantages

5. One of the main advantages of biopesticides is that they are less toxic and cause less harm than synthetic or chemical pesticides. Likewise, since biopesticides only target specific insects and pests, they will not affect other insects or animals. They

may also be safer for humans and the environment. In addition, the use of small quantities of biological pesticides can be very effective and cause little residue problems. However, for the effective use of biological pesticides, it is important to have extensive knowledge about pest management.

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