Which of the following is used as green manure?

Options

A. Azadirachta
B. Azolla
C. Crotalaria
D. Hevea

Answer

**Step-by-Step Solution:**

1. **Understanding Green Manure**: Green manure refers to crops that are grown specifically to be plowed back into the soil to improve its fertility. These crops are typically rich in nutrients, particularly nitrogen, and help enhance soil structure and organic matter content.

2. **Identifying the Options**: The question provides four options:
- A. Azardirecta
- B. Azola
- C. Croteleria
- D. Hedia

3. **Analyzing Each Option**:
- **A. Azardirecta**: While it is a plant, it is not commonly used as green manure.
- **B. Azola**: This is a type of aquatic fern and is not typically used as green manure.
- **C. Croteleria**: This is also known as Sun Hemp (Crotalaria juncea) and is widely recognized for its use as green manure.
- **D. Hedia**: This option does not correspond to a known green manure crop.

4. **Conclusion**: Based on the analysis, the correct answer is **C. Croteleria**, as it is specifically used as green manure due to its ability to supply organic matter and nitrogen to the soil.

5. **Final Answer**: Croteleria (Sun Hemp) is used as green manure.

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