Nitrogen fertilizer in the form of urea is subject to ammonia volatilization through the activity of the urease enzyme found ubiquitously in soil (Kissel et al., 2008). Nitrogen volatilization is especially prevalent when urea is applied to the soil surface, as in no-till systems when growers have not invested in sub-surface application tools. To decrease possible ammonia volatilization losses a number of products have been developed to delay urease activity.
Soil Science Extension
University of Wisconsin Madison