Urea, a white crystalline solid containing 46% nitrogen, is widely used in the agricultural industry as an animal feed additive and fertilizer Here we discuss it only as a nitrogen fertilizer.
Urea (46-0-0) usually has the lowest cost per pound of nitrogen compared to other single-element nitrogen fertilizers. However, urea undergoes unique chemical transformations when field applied and severe losses in efficiency may result if special management practices are not followed. The purpose of this fact sheet is to briefly describe urea transformations and to suggest how urea-N may be conserved with proper management in the field.
Fertilizer urea can be purchased as prills or as a granulated material. In the past, it was usually produced by dropping liquid urea from a “prilling tower” while drying the product. The prills formed a smaller and softer substance than other materials commonly used in fertilizer blends. Today, though, considerable urea is manufactured as granules. Granules are larger, harder, and more resistant to moisture. As a result, granulated urea has become a more suitable material for fertilizer blends.
| Main specifications | Norm | ||
|---|---|---|---|
| Urea Prilled | Urea Granulated | ||
| Mass portion of nitrogen (N) on a dry basis, %min | 46.2 | 46.2 | |
| Mass portion of biuret, %, max | 1.0 | 1.0 | |
| Moisture (determined by Fischer method), % max: | 0.5 | 0.5 | |
| Granulometry, % | 2 to 5 mm | – | 95 |
| 1 to 4 mm | 90 | – | |
| less than 1 mm | – | 2 | |
| more than 6 mm | none | None | |
| Color | white | white | |
| Static Strength | – | 2.5 kgs/granule | |
| Product free flowing, free from dust and harmful substances Urea is a non-combustible, fire and explosion proof substance |