Enrichment of soil with ammonia and nitrates by applying fertilisers is called

Options

A. industrial fixation
B. denitrification
C. ammonification
D. nitrogen assimilation.

Explanation

To answer the question "Enrichment of soil with ammonia and nitrates by applying fertilizers is called," we need to analyze the options provided and understand the processes involved in soil enrichment.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the process of enriching soil with ammonia and nitrates through the application of fertilizers.

2. **Identifying the Options**: The options provided are:
- Industrial fixation
- Denitrification
- Ammonification
- Nitrogen assimilation

3. **Analyzing Each Option**:
- **Industrial Fixation**: This process involves the artificial preparation of fertilizers that add nutrients (like ammonia and nitrates) to the soil. This aligns with the question as it directly relates to enriching the soil with these nutrients.
- **Denitrification**: This is the process where nitrates in the soil are converted back into nitrogen gas, which is not related to enriching the soil.
- **Ammonification**: This process converts organic nitrogen into inorganic nitrogen (ammonia), but it does not directly refer to the application of fertilizers.
- **Nitrogen Assimilation**: This refers to the incorporation of inorganic nitrogen (like nitrates and ammonia) into organic compounds by plants, but it does not describe the process of applying fertilizers.

4. **Conclusion**: Based on the analysis, the correct answer is **Industrial Fixation**, as it specifically refers to the enrichment of soil with ammonia and nitrates through the application of fertilizers.

### Final Answer:
The enrichment of soil with ammonia and nitrates by applying fertilizers is called **Industrial Fixation**.

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