Denitrification occurs seriosly in:

Options

A. Aerated soil with very low organic matter content
B. Aeratted soil with moderate amount of `N_(2)^(-)` and organic matter.
C. Water logged anaerobic soil with a high organic matter.
D. Water logged anaerobic soil with a low organic matter

Answer

**Step-by-Step Solution:**

1. **Understanding Denitrification**: Denitrification is a microbial process in which nitrates in the soil are converted into nitrogen gases, which are then released into the atmosphere. This process is crucial for the nitrogen cycle.

2. **Conditions for Denitrification**: Denitrification occurs most effectively in conditions that are warm, wet, and have a high abundance of nitrates. The denitrifying bacteria involved in this process require low oxygen levels and organic matter for energy.

3. **Analyzing the Options**:
- **Option 1: Irrigated soil with very low organic matter content**: This soil is aerated (contains oxygen) and has low organic matter, which is not suitable for denitrification. **(Incorrect)**
- **Option 2: Irrigated soil with a moderate amount of nitrogen and organic matter**: Again, this soil is aerated, meaning it has oxygen, which is not conducive for denitrification. **(Incorrect)**
- **Option 3: Waterlogged anaerobic soil with a high organic matter**: This condition provides low oxygen levels and high organic matter, making it ideal for denitrification. **(Correct)**
- **Option 4: Waterlogged anaerobic soil with a low organic matter**: While this soil is anaerobic, the low organic matter is not sufficient for denitrification. **(Incorrect)**

4. **Conclusion**: Based on the analysis, the best condition for denitrification to occur seriously is in **waterlogged anaerobic soil with a high organic matter**.

**Final Answer**: Waterlogged anaerobic soil with a high organic matter.

---