ALGAL BIOFERTILIZER Blue Green Algae (BGA) Blue Green Algae (BGA) or Cyanobacteria are the Algal Biofertilizers involved in Free living nitrogen fixation. Blue-green algae are Prokaryotic, Filamentous in nature and Ubiquitous in distribution. BGA are either single celled or consist of branched or unbranched filaments. More than 100 species of Blue Green Algae (BGA) can fix atmospheric Nitrogen. In BGA, Nitrogen fixation takes place in specialized cells called ‘Heterocyst’. Recently, some BGA without Heterocysts have also been found to fix nitrogen under special conditions like low oxygen tension. The algae that are generally used for field application are species of Aulosira , Tolypothrix , Scytonema , Nostoc , Anabaena and Plectonema as a mixture. The BGA are abundantly present in the habitats wherein moisture and light are adequately available. Though different groups of Algae are presen