Question

Which of the following is an excellent biofertilizer ?

• A. Azolla
• B. Marsilea
• C. Pteridium
• D. Salvina

Hint:

Azolla is a highly effective biofertilizer because it fixes nitrogen, improving soil fertility in rice cultivation.

Answer 1

The Correct Option is A

Step 1: Biofertilizer definition.
Biofertilizers are substances that contain living microorganisms which promote plant growth by increasing the supply or availability of primary nutrients to the host plant. These are natural fertilizers which help in maintaining soil fertility.
Step 2: Analyze the options.
- Azolla: A water fern that is a well-known biofertilizer. It is used as a nitrogen-fixing biofertilizer in rice fields. - Marsilea: While it is a water fern, it is not commonly used as a biofertilizer. - Pteridium: Known as bracken fern, is not commonly associated with biofertilization. - Salvinia: This is another aquatic fern but it does not have significant biofertilizer properties compared to Azolla.
Step 3: Conclusion.
Azolla is widely recognized for its ability to fix nitrogen in rice paddies and is used as an excellent biofertilizer.
Final Answer: \[ \boxed{Azolla} \]