Urea

Urea, also known as carbamide, is an organic compound with the chemical formula CO(NH2)2. This amide contains two -NH2 groups combined with a carbonyl (C=O) functional group.

Urea plays a significant role in the metabolism of nitrogen-containing compounds and is a fundamental nitrogen-containing substance in mammalian urine. It is a colorless, odorless solid that is highly soluble in water and is virtually non-toxic. It is neither acidic nor alkaline when dissolved in water. The body utilizes urea in many processes, most notably in nitrogen excretion. The liver produces it by combining two ammonia molecules (NH3) with one carbon dioxide (CO2) molecule in the urea cycle. Urea is commonly used as a nitrogen source in fertilizers and is an important raw material for the chemical industry.

Urea can be produced in a significant conceptual milestone in chemistry, as it contradicted the widely held vitalist doctrine that a substance could only be synthesized in a laboratory without the biological starting material, marking the time when a substance, conflicting with the doctrine, was recognized as a byproduct of life.

Urea serves as a raw material for producing two main classes of materials: urea-formaldehyde resins and urea-melamine-formaldehyde used in marine plywood.

Urea can be used to create urea nitrate, a highly explosive compound that is used industrially and as a component of some improvised explosive devices. It acts as a stabilizer in nitrocellulose-based explosives.

More than 90% of the world's industrial urea production is sent for use as nitrogen-containing fertilizers.

Urea has the highest nitrogen content among commonly used nitrogen fertilizers. Therefore, it has the lowest transportation cost per unit of nitrogen nutrient.

Due to the high nitrogen concentration in urea, even distribution is crucial. Application equipment should be properly calibrated and used correctly.

Due to the risk of germination damage, it should not come into contact with or near seed drills.

Urea can be dissolved in water as a spray or through irrigation systems.

In grain and cotton crops, urea is often applied before planting or during the last planting. In areas with high rainfall and sandy soils (where nitrogen can be lost through leaching) and when good rain is expected, urea can be side-dressed or top-dressed during the growing season. Top dressing is also popular for pasture and forage crops. In sugarcane cultivation, urea is side-dressed after planting and applied to each ratoon crop.

For irrigated crops, urea can be applied to the soil in a dry form or dissolved and applied through irrigation water. Urea dissolves in water under its own weight, but its solubility becomes more difficult as the concentration increases. Dissolving urea in water is an endothermic process; the solution temperature decreases as urea dissolves."