Nutrient Mobility in Plants: Understanding How Nutrients Move and Impact Crop Health
In the world of agronomy, understanding nutrient mobility is essential for diagnosing deficiencies, planning fertilization strategies, and improving crop productivity. Nutrient mobility refers to how easily a nutrient moves within the plant – especially from older tissues to newer growth. This characteristic influences how deficiency symptoms appear and how nutrients should be managed.
What is Nutrient Mobility?
Nutrients absorbed by plant roots are transported through the xylem and phloem. Their mobility determines whether they can be redistributed from older leaves to younger tissues when the supply is limited.
- Mobile nutrients can be translocated easily.
- Immobile nutrients remain fixed in the tissue where they were first deposited.
Classification of Nutrients by Mobility –
Highly Mobile Nutrients
These nutrients move freely from older to younger tissues –
- Nitrogen (N)
- Phosphorus (P)
- Potassium (K)
- Magnesium (Mg)
- Molybdenum (Mo)
Deficiency symptoms appear first in older leaves, as the plant reallocates these nutrients to support new growth.
Moderately Mobile Nutrients
These nutrients move to some extent –
- Zinc (Zn)
- Iron (Fe) (Limited mobility in phloem)
- Copper (Cu)
Symptoms may appear in middle-aged leaves or vary depending on crop species.
Immobile Nutrients
These nutrients are not easily translocated –
- Calcium (Ca)
- Sulfur (S)
- Boron (B)
Deficiency symptoms show up in young leaves or growing points, as these areas cannot draw nutrients from older tissues.
Why Mobility Matters in Agronomy –
Understanding nutrient mobility helps in:
Deficiency Diagnosis: Knowing where symptoms appear helps identify, which nutrient is lacking.
Fertilizer Strategy: Mobile nutrients can be applied to the soil, while immobile ones may need foliar application.
Crop-Specific Management: For example, calcium deficiency in tomato or boron deficiency in sugarcane requires targeted intervention.
Examples –
Nitrogen Deficiency in Maize: Yellowing starts from the older leaves due to high mobility.
Calcium Deficiency in Tomato: Blossom end rot appears in fruits and young tissues due to immobility.
Boron Deficiency in Grapes: Poor fruit set and distorted young leaves.
Conclusion –
Nutrient mobility is a key concept in plant nutrition. By understanding how nutrients move within plants, agronomists and farmers can make smarter decisions to ensure healthy crops and optimal yields.