Prilled Urea 46% incorporates 46% of nitrogen (N) in ureic form, simply absorbed through the leaves of plants. Absorption through the root system is slower, because urea in soil is converted (to be a result of enzymatic hydrolysis) into the ammonia form available for plants, and then into nitrate form. https://brightbookmarks.com/story21719240/about-how-dap-fertilizer-works