Nitrogen (N)

Role in plants

Nitrogen drives vegetative growth and is a core component of amino acids, proteins, enzymes, nucleic acids (DNA/RNA), and chlorophyll. It largely determines leaf area, canopy density, and yield potential.

Deficiency symptoms

• General pale green to yellowing (chlorosis)
• Symptoms appear first on older leaves
• Reduced growth and thin stems
• Premature senescence

Toxicity symptoms

• Excessively lush, soft growth
• Dark green foliage
• Increased disease susceptibility
• Delayed flowering and maturity
• Leaf tip burn under extreme excess

Natural sources

• Soil organic matter
• Atmospheric nitrogen via biological fixation
• Decomposing plant residues
• Manures and composts

Fertiliser sources

• Calcium ammonium nitrate
• Potassium nitrate
• Ammonium nitrate
• Ammonium sulphate
• Urea (less common in substrates)

Plant uptake forms

• NO₃⁻ (nitrate)
• NH₄⁺ (ammonium)