What is Urea 46% (Carbamide) and how does it work?
Urea is a naturally occurring compound contained in urine from mammals. It is manufactured by combining carbon dioxide with ammonia and is the most commonly used nitrogen fertilizer worldwide. With more than 46% nitrogen, it has the highest nutrient concentration among the commercially available solid nitrogen fertilizers. It can be applied in a solid prilled or granulated form. Although soluble in water, its application in fluid form is uncommon. In the soil, urea is converted from carbamide nitrogen to ammonium ions (NH4 +) by a series of enzyme reactions. Under normal soil conditions, the ammonium ions are absorbed by the soil (i.e. become attached to the negatively charged soil particles) and the nitrogen becomes available to the plant, either in its ammonium form or as nitrate following microbial oxidation. Urea derived ammonium behaves in exactly the same way as that from other ammonium based nitrogen fertilizers. This breakdown of urea to release ammonium ions normally occurs within a week.

• when urea fertilizer is incorporated or well washed into the soil
• when the soil has a high absorption capacity
• when the soil is sufficiently moist
• when the soil has a low pH
• at low temperatures

• persistent drought
• high temperatures and strong winds
• soil which has a low capacity for absorbing ammonium
• soil which has a high pH

May promote measurable gaseous losses of ammonia (NH3) which has been
converted from
ammonium and released to the atmosphere (after the application of fertilizer).