Urea is a granular, white colored, highly soluble fertilizer and contains the highest nitrogen among all nitrogenous fertilizers. It supplies the nitrogen need of plants through either soil or foliar application. Its chemical formula is CO(NH2)2 and contains 46% N (nitrogen). Since it contains carbon (C) and nitrogen in the form of NH2, it is known as an organic nitrogen source. Although it is highly soluble in water, its nitrogen (NH2) content cannot be directly taken up by plant roots.
In order for its nitrogen content to become available for plants, the urease enzyme (found in numerous coil microorganisms) in soils should convert urea into ammonium (NH4) nitrogen form through enzymatic reaction. That’s why; soil temperature and activity of microorganisms in the soil are important. Therefore, urea fertilizer is considered as a slow release fertilizer.
Agricultural Use
More than 90 percent of world urea production is destined for use as a nitrogen-release fertilizer. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use (46.7%). Therefore, it has the lowest transportation costs per unit of nitrogen nutrient
In order to supply plants with sufficient nitrogen, urea is very useful for almost all crops and for the fertilization of tobacco seedlings. When the plants are not supplied with sufficient nitrogen, the plant growth decelerates; leaves turn yellow, and yield decreases. Urea has a unique property that it can be used in all plant developmental stages.
Chemical industry
Urea is a raw material used in the manufacture of many important chemicals, such as:
1. Various plastics, especially the Urea-formaldehyde resins
2. Various adhesives, such as Urea-formaldehyde or the urea-melamine-formaldehyde used in marine plywood
3. Potassium cyanate, another industrial feedstock
4. Urea nitrate, an explosive
Urea has the ability to trap many organic compounds in the form of clathrates. The organic compounds are held in channels formed by interpenetrating helices comprising of hydrogen-bonded urea molecules. This behavior can be used to separate mixtures, and has been used in the production of aviation fuel and lubricating oils, and in the separation of paraffin.
As the helices are interconnected, all helices in a crystal must have the same molecular handedness. This is determined when the crystal is nucleated and can thus be forced by seeding. The resulting crystals have been used to separate racemic mixtures.
Automobile systems
Urea is used in SNCR and SCR reactions to reduce the NOx pollutants in exhaust gases from combustion, for example, from power plants and diesel engines. The BlueTec system, for example, injects water-based urea solution into the exhaust system. The ammonia produced by decomposition of the urea reacts with the nitrogen oxide emissions and is converted into nitrogen and water within the catalytic converter.
Other commercial uses
1. A stabilizer in nitrocellulose explosive
2. A component of animal feed, providing a relatively cheap source of nitrogen to promote growth
3. A non-corroding alternative to rock salt for road de-icing, and the resurfacing of snowboarding half pipes and terrain parks
4. A flavor-enhancing additive for cigarettes
5. A main ingredient in hair removers such as Nair or Veet
6. A browning agent in factory-produced pretzels
7. An ingredient in some hair conditioners, facial cleansers, bath oils, skin softeners, and lotions
8. A reactant in some ready-to-use cold compresses for first-aid use, due to the endothermic reaction it creates when mixed with water
9. A cloud seeding agent, along with other salts
10. A flame-proofing agent, commonly used in dry chemical fire extinguisher charges such as the urea-potassium bicarbonate mixture.
11. An ingredient in many tooth whitening products
12. An ingredient in dish soap
13. Along with ammonium phosphate, as a yeast nutrient, for fermentation of sugars into ethanol
14. A nutrient used by plankton in ocean nourishment experiments for geoengineering purposes
15. As an additive to extend the working temperature and open time of hide glue
16. As a solubility-enhancing and moisture-retaining additive to dye baths for textile dyeing or printing
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