Which type of microbes are found in paddy fields and act as biofertilizers?

Cyanobacteria

The type of microbes found in paddy fields and act as biofertilizers are cyanobacteria.

Cyanobacteria, also known as blue-green algae, are a group of photosynthetic bacteria that are commonly found in various aquatic and terrestrial environments, including paddy fields. These microbes play a crucial role in enhancing soil fertility and promoting plant growth through their ability to fix atmospheric nitrogen.

Cyanobacteria are autotrophic organisms, meaning they can produce their own food through photosynthesis. During photosynthesis, they utilize sunlight to convert carbon dioxide and water into organic compounds, while releasing oxygen as a byproduct. One of the unique abilities of cyanobacteria is their nitrogen-fixing capability.

In nitrogen fixation, certain species of cyanobacteria, such as Anabaena, Nostoc, and Oscillatoria, have specialized cells called heterocysts that can fix atmospheric nitrogen into ammonia. This ammonia is then converted into organic nitrogen compounds, such as amino acids and proteins, which are essential nutrients for plant growth. The process of nitrogen fixation increases the nitrogen content of the soil, making it available to plants and reducing the dependence on synthetic nitrogen fertilizers.

When cyanobacteria colonize the root zone of plants, they form a symbiotic relationship with the plants known as "association with root nodules." For example, Azolla, a small aquatic fern, hosts the cyanobacterium Anabaena in its leaf cavities. This association enables Azolla to fix nitrogen, benefiting the growth of rice plants when grown together in paddy fields.

Besides nitrogen fixation, cyanobacteria also contribute to soil fertility by adding organic matter to the soil. When these organisms die, their remains become part of the soil organic matter, providing essential nutrients for plant growth and improving soil structure and water retention.

In summary, cyanobacteria found in paddy fields act as biofertilizers by fixing atmospheric nitrogen, converting it into organic nitrogen compounds, and enriching the soil with essential nutrients that support the growth of paddy crops like rice. Their role as biofertilizers helps in sustainable agriculture by reducing the need for chemical fertilizers and promoting eco-friendly farming practices.