Urea fertilizer comes in different types. The two main types are prilled and granular. Urea can also be coated or uncoated. This guide explains the differences, so you can pick the right type for your needs.
Prilled Urea
Prilled urea is a form of nitrogen-rich solid fertilizer that has the ability to dissolve quickly in water.
Prilled urea is more commonly used today to resist breaking down when mixing with other fertilizer components like Potassium chloride.
It is also known as ice melting or deicing urea since it can reduce ice efficiently, even at very low temperatures ( -6 ◦C) .
Physical Properties of Prilled Urea
Prilled urea forms small, round particles. These particles have a large surface area. This helps water reach the urea faster, so it dissolves quickly.
Rain can wash away or break down some fertilizers fast. Prilled urea resists this well. It stays in the soil longer, so you apply it less often.
Prilled Urea Applications
- Direct use on soil or through irrigation, as a nitrogen fertilizer
- Used in NOx control systems, to reduce pollution from diesel engines
- Used as a nitrogen source in liquid fertilizers
- Used to melt snow and ice on runways
- Used in animal feed
- Used in some medicines
Granular Urea
Granular urea also has 46% nitrogen, the highest level among solid fertilizers. You can use it directly on soil, or mix it with phosphate and potash for a complete plant fertilizer. Granular urea works well with standard spreading equipment.
Physical Properties of Granular Urea
Granular urea has bigger particles and an uneven shape. It is stronger than prilled urea and less likely to break.
It releases nitrogen slowly. It can be a rich source of nutrients for plants. You can check the Urea page, to read the granular urea specifications.
Granular Urea Application
- Raw material for other fertilizers production
- Manufacturing of melamine used in melamine-methanal resins (used for the synthesis of melamine through a chemical reaction involving urea and formaldehyde.)
- Formation of important resins (urea-formaldehyde resin)
- Use in reducing air pollution from diesel engines in cars, buses, and lorries
Urea Types Comparison
Urea TypesSizeColorShapeHardnessSolubility OdorPrill Urea1-2.4 mmWhite or Light Gray Spherical SofterHighly SolubleOdorlessGranular Urea2-4 mmWhite IrregularHarderHighly SolubleOdorless
Coated vs Uncoated Urea
Some urea is treated with a small amount of formaldehyde during production. This creates a coating that makes the prill or granule stronger. It helps stop the urea from breaking apart or forming clumps during storage and shipping.
Uncoated urea has little or no formaldehyde. This matters for some uses, like making DEF (diesel exhaust fluid), where low formaldehyde is required. Coated urea has more formaldehyde treatment, for buyers who need extra strength during long transport.
In this article, we explained different types of urea. If you have any questions about other differences that we did not cover, please leave a comment.