Azolla is used in the cultivation of :

Options

A. Maize
B. Sorghum
C. Wheat
D. Rice

Answer

**Step-by-Step Solution:**

1. **Understanding Azolla**: Azolla is a rapidly growing aquatic fern that is known for its ability to fix atmospheric nitrogen due to its symbiotic relationship with nitrogen-fixing cyanobacteria (blue-green algae).

2. **Role of Nitrogen in Plants**: Nitrogen is an essential nutrient for plants as it plays a crucial role in photosynthesis, chlorophyll production, and overall plant growth. However, plants cannot utilize atmospheric nitrogen directly; it must be converted into usable forms.

3. **Application of Azolla in Agriculture**: Azolla is used as a biofertilizer in agriculture. The cyanobacteria associated with Azolla convert atmospheric nitrogen into forms that plants can absorb and utilize.

4. **Identifying the Crop**: The question asks which crop benefits from the use of Azolla. The options provided are maize, sorghum, wheat, and rice.

5. **Analyzing the Options**:
- **Maize**: While maize is an important crop, it does not typically rely on Azolla for nitrogen.
- **Sorghum**: Similar to maize, sorghum does not commonly use Azolla.
- **Wheat**: Wheat is another important crop but does not utilize Azolla in its cultivation.
- **Rice**: Rice is known to benefit significantly from the addition of Azolla, as the nitrogen fixed by the cyanobacteria enhances its growth and yield.

6. **Conclusion**: Based on the understanding of Azolla's role as a biofertilizer and its specific application in rice cultivation, the correct answer to the question is **rice**.

**Final Answer**: Azolla is used in the cultivation of rice.

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