In plant nutrition elements are classified as major or minor depending on

Options

A. Their availability in the soil
B. Their relative production in the ash obtained after burning the plants
C. The relative amounts required by the plants
D. Their relative importance in plant growth

Answer

To solve the question regarding the classification of elements in plant nutrition as major (macronutrients) or minor (micronutrients), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Classification**:
- Elements in plant nutrition are classified into two categories: macronutrients (major elements) and micronutrients (minor elements).

2. **Define Macronutrients and Micronutrients**:
- **Macronutrients** are elements that plants require in larger quantities. They are typically present in plant tissues in amounts greater than 10 millimoles per kg of dry weight.
- **Micronutrients** are needed in much smaller amounts, generally less than 10 millimoles per kg of dry weight.

3. **List of Macronutrients**:
- Common macronutrients include carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, potassium, calcium, and magnesium.
- Carbon, hydrogen, and oxygen are primarily sourced from carbon dioxide and water, while the others are absorbed from the soil.

4. **List of Micronutrients**:
- Micronutrients include elements such as iron, manganese, copper, molybdenum, zinc, boron, chloride, and nickel.

5. **Basis for Classification**:
- The classification into macronutrients and micronutrients is primarily based on the **relative amounts required by the plants**. Macronutrients are needed in larger quantities, while micronutrients are required in trace amounts.

6. **Conclusion**:
- Therefore, the classification of elements as major or minor in plant nutrition depends on their **quantitative requirements by the plants**.

### Final Answer:
In plant nutrition, elements are classified as major or minor depending on their quantitative requirements by the plants.

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