Which of the following mineral requires chelation in alkaline soil to increase its solubility:

Options

A. Iron
B. Manganese
C. Magnesium
D. Phosphorus

Answer

To solve the question regarding which mineral requires chelation in alkaline soil to increase its solubility, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks which mineral requires chelation in alkaline soil to enhance its solubility. Chelation is a process where metal ions bind with organic molecules (chelating agents) to form a complex that increases the solubility of the metal in the soil.

2. **Identify the Minerals**: The options provided are:
- Option 1: Iron
- Option 2: Manganese
- Option 3: Magnesium
- Option 4: Phosphorus

3. **Analyze Each Mineral**:
- **Iron**: Iron is known to have low solubility in alkaline soils. Chelation is often necessary to increase its availability to plants.
- **Manganese**: Manganese is generally more soluble in alkaline conditions and does not require chelation for availability.
- **Magnesium**: Magnesium is usually available in sufficient quantities in alkaline soils and does not require chelation.
- **Phosphorus**: Phosphorus is typically added through fertilizers and does not require chelation for its solubility.

4. **Conclusion**: Based on the analysis, iron is the mineral that requires chelation in alkaline soil to increase its solubility.

5. **Final Answer**: Therefore, the correct answer is **Iron**.