Prilled urea 46% consists of 46% of nitrogen (N) in ureic form, quickly absorbed via the leaves of plants. Absorption in the root system is slower, because urea in soil is converted (as being a result of enzymatic hydrolysis) into the ammonia form available for plants, then into nitrate form. https://geilebookmarks.com/story20198735/everything-about-urea-fertilizer-quantity