What is meant by 'nitrogen fixation' ? State two ways in which nitrogen gas of the atmosphere can be 'fixed' in nature to get nitrogen compounds in the soil.

Explanation

### Step-by-Step Solution:

1. **Definition of Nitrogen Fixation**:
- Nitrogen fixation is the process through which atmospheric nitrogen (N₂) is converted into a more reactive and soluble form, such as nitrites (NO₂⁻) and nitrates (NO₃⁻), which can be utilized by plants. This process is essential for incorporating nitrogen into the soil, making it available for plant uptake.

2. **First Way of Nitrogen Fixation**:
- **Lightning**: During thunderstorms, lightning produces high temperatures and pressure, which can cause nitrogen gas in the atmosphere to react with oxygen. This reaction forms nitrogen oxides, which then dissolve in rainwater to form nitrites and nitrates. These compounds are carried to the soil, enriching it with nitrogen.

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