Urea [N-46-0-0] (Taranaki) Traditional Cache
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Urea [N-46-0-0] (Taranaki)
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A cache with a view of the the Ammonia Urea Plant at Kapuni.
Urea or carbamide is an organic compound with the chemical formula (NH2)2CO. The molecule has two amine (-NH2) groups joined by a carbonyl (C=O) functional group.
Urea serves an important role in the metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. It is solid, colourless, and odorless (although the ammonia which it gives off in the presence of water, including water vapor in the air, has a strong odor). It is highly soluble in water and non-toxic. Dissolved in water it is neither acidic nor alkaline.
Urea is widely used in fertilizers as a convenient source of nitrogen, and this was why this plant was built in the early 1980s as part of Muldoon's Thing Big campaign. I worked on building this plant during the construction phases.
Urea was first discovered in urine in 1773 by the French chemist Hilaire Rouelle. In 1828, the German chemist Friedrich Wöhler obtained urea by treating silver isocyanate with ammonium chloride
AgNCO + NH4Cl ? (NH2)2CO + AgCl
More than 90% of world production of urea is destined for use as a nitrogen-release fertilizer. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use. Therefore, it has the lowest transportation costs per unit of nitrogen nutrient. The standard crop nutrient rating of urea is 46-0-0, hence the cache name.
Because of the high nitrogen concentration in urea, it is very important to achieve an even spread. The application equipment must be correctly calibrated and properly used. Drilling must not occur on contact with or close to seed, due to the risk of germination damage. Urea dissolves in water for application as a spray or through irrigation systems. Top-dressing is also popular on pasture and forage crops.
Urea will dissolve in its own weight in water, but it becomes increasingly difficult to dissolve as the concentration increases. Farmers in this area usually apply before forecast rain. As a practical guide, when preparing urea solutions for fertigation (injection into irrigation lines), dissolve no more than 30 kg urea per 100 L water.
Urea absorbs moisture from the atmosphere and therefore is typically stored either in closed/sealed bags on pallets, or, if stored in bulk, under cover with a tarpaulin. As with most solid fertilizers, storage in a cool, dry, well-ventilated area is recommended.
The Kapuni plant in Taranaki produces all of NZ's urea, from natural gas, and a high proportion of it is exported. On September 17 2009, the plant produced its 5 Millionth tonne of N-rich Urea.
Additional Information: Ballance, Wikipedia.
Additional Hints
(Decrypt)
R-nfl? Cbfgrq? Fubhyq or boivbhf. Srry serr gb gnxr n cubgb bs gur cynag naq cbfg jvgu lbhe ybt.