Question

Which of the following pairs of type of nutrient nutrient is correctly matched?

• A. Micronutrient-Calcium.
• B. Macronutrient-Zinc
• C. Micronutrient-Boron
• D. Macronutrient-Iron

Answer 1

Answer:

C. Micronutrient-Boron

Nutrient Classification in Agriculture

• Macronutrients: These are required by plants in relatively large amounts. They are further divided into:
  • Primary Macronutrients: Nitrogen (N), Phosphorus (P), and Potassium (K).
  • Secondary Macronutrients: Calcium (Ca), Magnesium (Mg), and Sulfur (S).
• Micronutrients: These are essential elements required by plants in very small quantities (often measured in parts per million). Despite their low required concentration, they are critical for plant growth, metabolism, and enzyme function.
• Examples of Micronutrients: Boron (B), Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Molybdenum (Mo), Chlorine (Cl), and Nickel (Ni).

Key Facts for Competitive Exams

• Boron Deficiency: Often leads to 'hollow heart' in groundnut, 'internal necrosis' in mango, and poor seed/fruit set in various crops.
• Essentiality Criteria: According to the Arnon and Stout criteria (1939), an element is essential if a plant cannot complete its life cycle without it, the element cannot be replaced by another, and it is directly involved in plant metabolism.
• Soil pH Influence: The availability of micronutrients in soil is heavily influenced by pH; for example, Iron and Manganese availability increases in acidic soils, while Molybdenum availability increases in alkaline soils.