Nitrogen fixing bacteria (Azotobacter, Beijerinckia, Clostridium, Klebsiella, Azospirillum, Herbaspirillum, Rhizobium, Bradyrhizobium, etc.) and cyanobacteria (Anabaena, Aulosira, Nostoc, etc.) have the potential to be used as bio-fertilizers to fulfill nitrogen requirement of the soil in sustainable agriculture.

@ Rk, the most important microorganisms are Azotobacter, Azospirillum, Rhizobium, cyanobacteria, phosphorus and potassium solubilising microorganisms and mycorrhizae

Rk Naresh Azotobacter, Azospirillum, Rhizobium, cyanobacteria, phosphorus

Infact , no microorganism can fulfill the N-requirement of crop, since microbes are the just partial supplement to crop nutrient requirement .

Rhizobia spp. is an important microorganism forming a mutual beneficial association with plants, especially leguminous plants. Nitrogen fixation by symbiotic relationship between Rhizobia spp. and plant provide 75 % of required nitrogen hence promoting growth and improving soil fertility. On the other hand, the arbuscular mycorrhizal fungus is also an important microorganism because it provides the plant with phosphorus a nutrient that contributes to the plant carrying out biological nitrogen fixation. So, somebody may need all these microorganisms to better improve nitrogen sustainably.

The best option is seed treatment with Rhizobium culture in case of leguminous crops because symbiotic relation is beneficial to both host and bacterium. In case of cereals Azotobacter can be best choice.

Biofertilizers add nutrients through the natural processes of fixing atmospheric nitrogen, solubilizing Phosphorus, and stimulating plant growth through the synthesis of growth promoting substances. Examples are: Azospirillum, Rhizobium and others

Different strains of microorganisms can be used for nitrogen fixation but in case of acidic soil Bradyrhizobium is preferred over Rhizobium. In several institutes a single strain or formulation of microorganisms like Azophos (Azotobacter+PSB) is available and sometimes the combination of 3 is also available. The strain to be used is sometimes crop specific & the other factors like soil pH should also be considered.

For optimizing the application of microbes as sustainable agriculture components, the combined use of biological, mineral and organic resources is a promising approach. Microbial inoculants are important components of efficient integrated pl. Nurient management system, whereas mineral fertilization provide high amount of nutrients. Both resources interact synergistically to improve plant nutrition. Co-inoculation with Azotobacter chroococcum, Azospirillum brasilense, Azospirillum lipoferum, Sinorhizobium spp., Burkholederia spp. Acetobacter diazotrophicus, Pseudomonas spp. Improve the yield of multiple crops including legumes with reduced nitrogen fertilization. Sinorhizobium melilotti RMP and P. aeruginosa GC2 along with urea and DAP is effective for Brassica juncea.

Infact, biofertiisers are only supplemental and not substitutes.

You might also take a look at an opposite question - how does the choice of fertilizer impact the microbial population. The article below is an excellent review

Bob

Article Fertilization and Soil Microbial Community: A Review

There are numerous microorganisms have potentiality to supply Nitrogen into soil by fixation process. Among them Azotobacter and Rhizobium are the major 2 which contribute more in sustainable agriculture.

The Nitrogen fixing bacteria (Rhizobium, Azotobacter, Beijerinckia, Clostridium, Klebsiella, Azospirillum, Herbaspirillum, Bradyrhizobium, etc.) and cyanobacteria (Anabaena, Aulosira, Nostoc, etc.) under rice conditions, have the potential to be used as bio-fertilizer as a supplement they didn't to fulfill nitrogen requirement of the crop but decrease the heavy load of inorganic fertilizers and also maintain the soil in sustainable agriculture.

Yes of course ,should that we reduce from mineral fertilizers with using biofertlizers

Rhizobium as well as cyanobacteria are capable to perform in conversion of atmospheric nitrogen in the form of nitrates and nitrites in the soil as mutually.

Azotobacter, Beijerinckia, Clostridium, Klebsiella, Azospirillum, Herbaspirillum, Rhizobium, Bradyrhizobium, etc.are the functional nitrogen fixing bacteria along with cyanobacteria (Anabaena, Aulosira, Nostoc, etc) can be used in sustainable agriculture

We can use non- symbiotic bacteria such as Azotobacter and Azospirillum. These bacteria does not require host plant for nitrogen fixation @ r k naresh

@ Laxman, Azotobacter does not require the host plant as they are free living but Azospirillum require the plant root association.

Rhizobium, Azotobacter, Azospirillum, and blue-green algae (BGA) are biofertilizers which they are play vital in boosting up symbiosis relation with soil fertility enhancement and leads sustainable agriculture by keeping fertility balance.

Cyanobacteria an important microbial which contribute for

a Vital role in sustainable agriculture.

Different PGPRs such as Azotobacter, Azospirillum and Rhizobium sp are utilised for Nitrogen fixation. Amongst these, Azotobacter and Azospirillum are free living while Rhizobium are bound with root nodules of leguminous crops. Rest other organisms such as Anabena azollae, Cyanobacterial sp are also potent nitrogen fixers.

Cyanobacteria

Biological nitrogen fixing microbes (BNF). BNF allows the replenishment of total nitrogen content and the fixed nitrogen regulates the crop growth and yield.

I agree with Anoop Kumar Srivastavs, Definitely no but Rhizobium is relatively more effective and widely used biofertilizer. Rhizobium, in association wit legumes, fixes atmospheric N. The legumes and their symbiotic association with the rhizobium bacterium result in the formation of root nodules that fix atmospheric N. The majority of cyanobacteria can fix nitrogen from the atmosphere and several species including Anabaena sp., Nostoc sp., and Oscillatoria angustissima is known to be effective cyanobacterial based bio fertilizers. Nitrogen fixation is carried out naturally in soil by microorganisms termed diazotrophs that include bacteria, such as Azotobacter, and archaea.

Several microorganisms, including nitrogen-fixing soil bacteria and cyanobacteria, phosphate-solubilizing bacteria, molds, and mushrooms, are routinely utilized as biofertilizers. Similarly, microorganisms that produce phytohormones are used in the production of biofertilizers. Algae like blue-green algae are widely used as biofertilizers as they are free-living microbes that fix the atmospheric nitrogen for the plants. They are cyanobacteria that prefer wet and marshy lands. Biofertilizers are the living microbes that inhabit the root zone or the interior plant parts. These microbes promote growth, productivity, and physiological properties of plant either directly or indirectly and hence, are also said as plant growth-promoting rhizobacteria.

Several microorganisms have the potential to be used as biofertilizers to fulfill the nitrogen requirement of the soil in sustainable agriculture. Here are some examples:

These microorganisms have the potential to be used as biofertilizers to fulfill the nitrogen requirement of the soil in sustainable agriculture. They provide a natural and environmentally friendly alternative to chemical fertilizers, which can have negative impacts on the environment and human health.

Dear Dr Fayaz Hussain thank you for your contribution to the discussion

Cyanobacteria can degrade a wide range of pollutants and perform different roles in the soil ecosystem to sustain soil fertility. Cyanobacteria are emerging microorganism for sustainable agricultural development. There are mainly 6 types of the Microbes that are used as the Biofertilizers. These Microbes are Rhizobia, Azotobacter, Azospirillum, Blue-green algae, Azolla, and Phosphate-solubilizing Microorganisms. The Rhizobium or Bradyrhizobium bacteria colonize the host plant's root system and cause the roots to form nodules to house the bacteria. The bacteria then begin to fix the nitrogen required by the plant. This fixation of atmospheric nitrogen by microbes is called biotic nitrogen fixation. e.g. bacteria and the plant form a mutualistic interaction in nitrogen fixation. Rhizobium and Bradyrhizobium species enter the roots of legumes and form root nodules. Then they convert atmospheric nitrogen into nitrogen compounds. Biopesticides are naturally occurring compounds or agents that are obtained from animals, plants, and microorganisms such as bacteria, cyanobacteria, and microalgae and are used to control agricultural pests and pathogens. Bacteria such as Rhizobium, Azotobacter, and certain blue-green algae present in the soil fix atmospheric nitrogen in the soil. But Rhizobium plays a vital role in nitrogen fixation. A wide variety of bacterial genera, including Agrobacterium, Alcaligenes, Arthrobacter, Bacillus, Enterobacter, Erwinia, Pseudomonas, Rhizobium, Serratia, Stenotrophomonas, Streptomyces, and Xanthomonas have been described to have plant disease protection activity against fungal and bacterial pathogens.