Urea 46% Nitrogen
The world's most concentrated solid nitrogen fertiliser at 46% N. Used as a top-dress to push vegetative growth, extend green leaf area, and support grain fill in cereals. The most cost-effective source of nitrogen per kilogram.
How to Use
Use as Top-Dress Only
Never apply Urea at planting in direct contact with seed — it converts to ammonia gas in soil which is toxic to germinating seeds. Use NPK 20-10-10 or DAP at planting, then top-dress with Urea 3–5 weeks later.
Apply at the Right Stage
For maize: apply at knee-high stage (4–5 weeks after emergence) and again at tasseling if needed. For vegetables: apply every 3–4 weeks during the growing period. Do not apply within 4 weeks of harvest as it can cause leafy growth at the expense of fruit/grain.
Broadcast or Band
Broadcast: spread granules evenly across the field at 100–150 kg/ha and incorporate by light cultivation or rainfall. Band: place 5 cm beside crop rows and cover with soil immediately to reduce ammonia loss.
Apply Before Rain
Urea must be incorporated by rainfall or irrigation within 24–48 hours of application. If applied to dry soil with no rain expected, nitrogen loss from volatilisation can exceed 30%. Timing is critical for Urea efficiency.
For Foliar Application
Urea can be dissolved for foliar feeding at 1–2% solution (100–200 g per 10 L). Apply in the cool of the evening. Do not exceed 2% concentration as leaf burn can occur, especially on young plants or in hot weather.
Safe Storage
Urea is hygroscopic and absorbs atmospheric moisture rapidly. Store in sealed bags on pallets in a dry building. Once opened, fold and clip the bag tight. Never store near nitrate fertilisers (CAN, ammonium nitrate) — moisture can cause dangerous reactions.
Key Features
Highest Nitrogen Content
46% N is double the nitrogen content of CAN and 2.3× that of ammonium sulphate — the most nitrogen per kilogram of any solid fertiliser.
Lowest Cost per kg N
Because of its high concentration, Urea delivers nitrogen at the lowest cost per kilogram of N compared to all other solid nitrogen sources.
Universal Crop Use
Suitable for maize, rice, wheat, vegetables, sugarcane, cotton, tea, and all horticultural crops — the most versatile nitrogen source available.
Fully Water Soluble
Dissolves completely in water for foliar feeding, drip fertigation, or incorporation by irrigation. No insoluble residues or tank blockages.
Soil pH Neutral
Unlike ammonium sulphate (which acidifies soil), Urea has a near-neutral long-term pH effect when used at recommended rates — suitable for all soil types.
Fast Acting
Urea converts to ammonium in the soil within 2–7 days (temperature-dependent), providing rapidly available nitrogen for quick crop response.
Efficiency Tips & Warnings
- Add a urease inhibitor (NBPT) if available locally — it slows conversion to ammonia and reduces volatilisation by up to 50%, especially important in hot, humid Tanzanian conditions.
- Never apply on waterlogged soils — anaerobic conditions convert nitrogen to N₂ gas (denitrification) and you lose the investment entirely.
- On slopes, apply in bands or incorporate immediately — Urea dissolved by rainfall can run off before it is absorbed, causing both crop loss and water pollution.
- Urea burns: if granules land in leaf whorls or on wet leaf surfaces, they can cause contact burn. For maize top-dressing, apply between rows not onto leaves — broadcasting by hand on a calm day gives best results.
- For drip irrigation (fertigation), dissolve completely in a separate bucket before adding to the drip tank. Always flush drip lines with clean water for 20 minutes after fertigation.
