What is urea fertiliser? It is a granular, white, easy and very soluble fertiliser with the highest nitrogen content among nitrogen fertilisers. It meets the nitrogen needs of plants both through soil and foliar application. Its formula is CO(NH2)2 – 46% N (nitrogen). It is an amide fertiliser due to the presence of carbon (C) in its structure and nitrogen in the form of NH2. Although it dissolves easily in water, the nitrogen (NH2) in its structure is not in a form that can be taken up immediately by plant roots. In order for the nitrogen in its structure to become useful, urea bacteria in the soil must convert urea into ammonium (NH4) nitrogen by enzymatic reaction. The temperature of the soil and the amount (concentration) of urea bacteria in the soil are important for this. For this reason, urea fertiliser belongs to the slow-acting fertiliser group. Where is it used? Urea is very useful in almost all types of crops and in fertilising tobacco seedlings to meet the nitrogen requirement of plants. When urea is insufficient, plant development slows down, leaves turn yellow and yield decreases. Urea has the ability to be used in all stages of plant development. Method of use Urea fertiliser can be applied as a base fertiliser (subsoil) with or before planting, or as a top fertiliser. In both cases, if the soil has a very sandy and loamy texture, a large part of the urea fertiliser is washed deep into the soil by excessive rainfall or improper irrigation. Therefore, it is necessary to pay attention to irrigation when using nitrogen fertiliser in the form of urea on such soils. When urea fertiliser is spread on the soil surface as a top fertiliser in plants such as wheat and barley, it is hydrolysed by solar energy depending on the air temperature, especially in calcareous soils with high pH values, and a nitrogen loss of 30-40% may occur. Nitrogen loss is less in urea fertiliser applied by mixing into the soil. Two-nutrient (such as 20.20.0) and three-nutrient (such as 15.15.15) compound fertilisers usually contain nitrogen in the form of urea. However, it is preferred that the nitrogen in foliar fertilisers is in the form of urea, as it is absorbed much faster and shows its effect immediately. More information on this subject can be found in the “Fertilisation Recommendations” section of the website.