Prilled urea 46% consists of 46% of nitrogen (N) in ureic form, conveniently absorbed via the leaves of plants. Absorption through the root system is slower, because urea in soil is transformed (as a result of enzymatic hydrolysis) into the ammonia form available for plants, and then into nitrate form. https://socialmarkz.com/story10831191/fascination-about-npk-fertilizer-home-made