Blue Green Algae (BGA)

Blue green algae are autotrophic and nitrogen fixing organisms unlike heterotrophic and symbiotic nitrogen fixing microbes discussed above. They manufacture their food by photosynthesis, as they have chloroplasts. Hence, they can live independently. BGA like Anabaena and Nostoc are found to live on soil, rocks. They have potentiality to fix large atmospheric nitrogen (upto 20 - 25 kg/ha). On completion of their life cycle, they add large quantity of nitrogen to the soil. Conditions necessary to grow BGA (light, adequate moisture, 20-30^oC temperature, 70-75% humidity) must be maintained in the soil, in order to grow BGA successfully.