Azolla pinnata is a water fern that is used as a biofertilizer in rice cultivation. It is a nitrogen-fixing plant that forms a symbiotic relationship with a cyanobacterium, Anabaena azollae, which is capable of fixing atmospheric nitrogen. This nitrogen is then made available to the rice plants, resulting in higher yields.

Benefits of using Azolla pinnata as a biofertilizer:

1. Nitrogen fixation: The symbiotic relationship between Azolla pinnata and Anabaena azollae results in the fixation of atmospheric nitrogen, which is then made available to the rice plants. This reduces the need for synthetic nitrogen fertilizers, which are expensive and can have negative environmental impacts.

2. Organic matter: Azolla pinnata is a rich source of organic matter, which helps to improve soil fertility and structure. This can lead to better water retention and nutrient availability for the rice plants.

3. Weed control: The dense mat of Azolla pinnata on the surface of the water helps to suppress weed growth, reducing competition for nutrients and sunlight with the rice plants.

4. Pest control: Azolla pinnata has been shown to have insecticidal properties, which can help to control pests in rice fields.

5. Cost-effective: Azolla pinnata is easy to cultivate, requires minimal inputs, and can be propagated quickly. This makes it a cost-effective alternative to synthetic fertilizers.

In conclusion, the use of Azolla pinnata as a biofertilizer in rice cultivation has been shown to increase yields by over 50%. Its benefits include nitrogen fixation, organic matter, weed and pest control, and cost-effectiveness. It is a sustainable and eco-friendly alternative to synthetic fertilizers, which can have negative environmental impacts.

Azolla plays a very important role in rice production. Azolla and its nitrogen-fixing partner, Anabaena, have been used as green manure to fertilize rice paddies and increase production. With the help of Azolla, rice can be grown year after year, several crops a year, with little or no decline in productivity; hence no rotation of crops is necessary