Urea is the most traded nitrogen fertilizer in the world, and its specification sheet looks simple: 46-0-0 plus a few parameters. But each line on that sheet has commercial consequences, and knowing which ones matter for your application is the difference between a smooth shipment and a claim.
Total Nitrogen: the headline number
46% minimum nitrogen is the standard for solid urea — the highest N content of any solid nitrogen fertilizer. The number is rarely the problem in trade disputes; it is the anchor from which everything else is negotiated. Prices are quoted per tonne of physical product, so every fraction of a percent of nitrogen is value.
Biuret: the quiet variable
Biuret is a urea decomposition product that forms in production. At moderate levels it is harmless to soil application, but it is phytotoxic above certain concentrations — relevant for foliar application and fertigation — and it is a critical parameter for industrial users and DEF blending. Prilled material is typically specified at or below 1.0%; if you spray urea solutions on crops or process urea industrially, push this parameter in your contract.
Moisture and caking: the shipping risk
Urea is hygroscopic: it absorbs moisture from humid air and, once it starts, cakes into lumps. This is the single most common quality complaint in bagged urea imports, and it is usually a logistics problem rather than a production problem — bags stored in humid warehouses, containers without lining, or cargo stuffed wet. Buyers importing to tropical climates should treat packaging quality and container preparation as part of the specification.
Particle size: prilled vs granular
| Parameter | Prilled urea | Granular urea |
|---|---|---|
| Process | Prilling tower | Granulation |
| Typical size | 0.85 – 2.80 mm | 2.00 – 4.75 mm |
| Hardness / dust | Softer, more dust | Harder, low dust |
| Best for | Dissolution, hand spreading | Mechanical spreading, NPK blending |
For blending plants, particle size matching with the other nutrients (DAP, MAP, MOP) prevents segregation during handling and spreading. State your blending mix when requesting a quotation so the producer can confirm the size distribution.
One rule above all
Never accept a specification sheet as the delivered quality. The document that matters is the COA for the production lot, and ideally an independent surveyor’s certificate for the shipped cargo. Build both into your contract terms from the first order.
SINO STARCO CHEMICAL exports prilled and granular urea 46-0-0 with manufacturer COA per lot and third-party inspection available. Contact us with your destination market and application for a specification-matched quotation.