GENERAL KNOWLEDGE

Detailed explanation-1: -Azolla is a fern, which harbours blue green algae on its leaves. The blue green algae are good nitrogen fixers, which makes Azolla a biofertilizer. It is frequently used in rice fields.

Detailed explanation-2: -Blue-green algae (BGA) have been found to be an easily available and economically cheap resource material for production and use as biofertilizers. These are free-living, photoautotrophic micro-organisms, many of which also fix atmospheric nitrogen and are found in abundance in rice fields.

Detailed explanation-3: -Asia; a blue-green algae (Anabaena azollae) is always found in pockets on the leaves of Azolla and helps convert nitrogen to a form usable by other plants (see nitrogen-fixation), thus greatly increasing the productivity of rice paddies where the fern occurs.

Detailed explanation-4: -Acutodesmus dimorphus, Spirulina platensis Chlorella vulgaris, Scenedesmus dimorphus, Anabaena azolla, and Nostoc sp. are some of the green microalgae and cyanobacteria species that have been successfully used as bio fertilizers to boost crop growth.

Detailed explanation-5: -Leaves of Azolla contain blue-green algae Anabaena azollae which fixes atmospheric Nitrogen. Anabaena pinata is also a good biofertilizer.