Nitrogen Deficiency
Pathogen: Abiotic — nutrient stress · Affects All crops
Nitrogen deficiency is the most common nutrient problem in agriculture because nitrogen is the most mobile macronutrient in the soil — it leaches with heavy rain and is drawn out fastest by fast-growing crops. Unlike a pathogen, it is entirely reversible with the right fertilization, often within days of a foliar application.
Symptoms
- Uniform pale-green to yellow older leaves
- Stunted growth and thin stems
- Reduced tillering in cereals
Causes
- Leached soils after heavy rain or over-irrigation
- Low soil organic matter
- Cold soils that slow nitrogen mineralization
Treatment
- Side-dress with urea (46-0-0) or ammonium sulfate at label rate
- Foliar spray of 1–2% urea for a rapid response
- Incorporate composted manure
Prevention
- Test soil annually and follow an NPK plan
- Rotate with legumes to fix nitrogen
- Use cover crops to build organic matter
Frequently asked questions
How fast does a plant recover from nitrogen deficiency?
A foliar urea spray can show visible greening within 3–5 days, while a soil side-dress typically takes 1–2 weeks to fully correct growth and color.
Why do older leaves yellow first with nitrogen deficiency?
Nitrogen is mobile within the plant, so it is pulled from older leaves and relocated to support new growth, causing the oldest leaves to yellow first.
NPK Fertilization Plan
Balanced macronutrient program based on soil test results.
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