which of the following plant is used as green manure ?

Options

A. Crotalaria juncea
B. Vigna sinensis
C. Barseem
D. All the above

Answer

**Step-by-Step Solution:**

1. **Understanding Green Manure:**
- Green manure refers to plants that are grown primarily to be incorporated back into the soil to improve its fertility. These plants are usually legumes that can fix nitrogen, which is essential for plant growth.

2. **Analyzing the Options:**
- The question provides four options:
1. Crotalaria juncea
2. Vigna sinensis
3. Barcium
4. All of the above

3. **Evaluating Crotalaria juncea:**
- Crotalaria juncea, commonly known as sunn hemp, is a plant that is widely used as green manure. It is known for its ability to improve soil fertility and can also be used as fodder for livestock.

4. **Evaluating Vigna sinensis:**
- Vigna sinensis, commonly known as cowpea, is another legume that is extensively used as green manure. It has a high nitrogen-fixing capacity and can be incorporated into the soil to enhance its nutrient content.

5. **Evaluating Barcium:**
- Barcium (likely referring to a legume like 'Bacillus' or 'Bacopa') is also a nitrogen-fixing legume. It helps in improving soil quality and preventing soil erosion.

6. **Conclusion:**
- Since all three plants mentioned (Crotalaria juncea, Vigna sinensis, and Barcium) are used as green manure, the correct answer is option 4: "All of the above."

**Final Answer:**
The plant used as green manure is: **All of the above (Crotalaria juncea, Vigna sinensis, Barcium).**

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