You may or may not have heard the term Enhanced Efficiency Fertilizer (EEF). Either way, a good place to start is with the term’s official definition: Fertilizer products with characteristics that allow increased plant uptake and reduce the potential of nutrient losses to the environment (i.e. gaseous losses, leaching or runoff) when compared to an appropriate reference product. (AAPFCO, Official 2009)
Although the term enhanced efficiency fertilizer is relatively new, there are products that fit this classification that have been around for more than a half-century. These include methylene urea (MU) and urea-formaldehyde (UF) fertilizers. There are also sulfur-coated urea and polymer-coated urea products, natural organic fertilizers and stabilized nitrogen products incorporating urease and/or nitrification inhibitors. They all fit under the EEF umbrella.
You should become familiar with the term enhanced efficiency fertilizer. Some states are starting to pass more specific regulations on nitrogen (N) application. They are using this terminology and are making fertilizer use rate exceptions or allowances for the application of EEFs. By remembering this term, you can be prepared if you see it in your state or locality in the future.