UREA KNOWLEDGE

The Urea or can be called carbamide is a"water soluble" & an organic compound with the chemical formula (NH2)2CO. The molecule has two amine (-NH2) residues joined by a carbonyl (-CO-) functional group.

We can say that more than 90% of world production is destined for use as a nitrogen-release fertilizer, because of its high nitrogen content (46.00% by weight), urea is a popular fertilizer.

In the soil, it hydrolyses back to ammonia and carbon dioxide. The ammonia is oxidized by bacteria in the soil to nitrate which can be absorbed by the plants.

Urea is also used in many multi-component solid fertilizer formulations.

Urea is highly soluble in water and is, therefore, also very suitable for use in fertilizer solutions.

For fertilizer use, granules are preferred over prills because of their narrower particle size distribution which is an advantage for mechanical application.
Urea can be applied in various forms, it can be spread in bulk alone or can also be mixed with other fertilizers before application.

However Urea should be preferably spread alone so as to avoid unevenness in the field.

In case of preparing blended mixtures with other fertilizers the best ones to suit its density are monoammonium phosphate (11-52-0) or diammonium phosphate (18-46-0).

When blended together, these are easily spread uniformly across the cultivated land.

The most common impurity of synthetic urea, biuret, must be present at less than 2%, as it impairs plant growth.

During summer, urea should be spread just before, or during rain to reduce possible losses from volatilization (process wherein nitrogen is lost to the atmosphere as ammonia gas).

Urea should not be mixed for any length of time with other fertilizers, as problems of physical quality may result.

 Because of the high nitrogen concentration in urea, it is very important to achieve an even spread. 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.

In grain and cotton crops, urea is often applied at the time of the last cultivation before planting.

It should be applied into or be incorporated into the soil. In high rainfall areas and on sandy soils (where nitrogen can be lost through leaching) and where good in-season rainfall is expected, urea can be side- or top-dressed during the growing season.

In irrigated crops, urea can be applied dry to the soil, or dissolved and applied through the irrigation water.

Urea will dissolve in its own weight in water, but it becomes increasingly difficult to dissolve as the concentration increases. Dissolving urea in water is endothermic, causing the temperature of the solution to fall when urea dissolves.

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.

In foliar sprays, urea concentrations of 0.5% – 2.0% are often used in horticultural crops. As urea sprays may damage crop foliage, specific advice should be sought before use.

Low-biuret grades of urea should be used if urea sprays are to be applied regularly or to sensitive horticultural crops.

Like most nitrogen products, urea absorbs moisture from the atmosphere. Therefore it should be stored either in closed/sealed bags on pallets, or, if stored in bulk, under cover with a tarpaulin. As with most solid fertilizers, it should also be stored in a cool, dry, well-ventilated area.