How are Rhizobium cultures used as biofertilisers?

Explanation

**Step-by-Step Solution:**

1. **Understanding Rhizobium Bacteria:**
- Rhizobium is a type of bacteria that is commonly found in the soil. It is known for its ability to fix atmospheric nitrogen.

2. **Association with Legume Plants:**
- When Rhizobium bacteria come into contact with legume plants (such as peas, beans, and clover), they form a symbiotic relationship. The plants develop specialized structures called root nodules.

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