Enhanced efficiency fertilizers (EEF) are forms of fertilizer, including nitrogen, designed to reduce nutrient losses to the environment. In doing so they make more nutrients available to crops.
Nitrogen EEFs may be contrasted with “traditional” forms of N which include anhydrous ammonia, granular urea, ammonium sulfate, and urea-ammonium nitrate solutions. Traditional forms of nitrogen are prone to N loss through leaching, runoff, volatilization or denitrification.
Nitrogen EEFs may be formulated with an extra additive or they may incorporate a special coating. Both methods are designed to slow or control the release of nitrogen.
Enhanced efficiency fertilizers fall into three groups:
– Inhibitors: Products with limited protection times. Urease inhibitors, for example, protect urea from volatilization while nitrification inhibitors protect against leaching and denitrification. Urease inhibitor brands include Agrotain®, Agrotain Plus®, Super U® and NutriSphere-N®. Nitrification inhibitors include Agrotain Plus, Super U, Guardian®, N-Serve®, Super U®, InstinctTM, Entec® and NutriSphere-N.
– Slow release products: Non-coated products that release N at a slow rate (as opposed to a controlled rate – see below). This category includes sulphur-coated urea reaction products. Slow release brands include Nitamin NFusion®, CoRoN®, N-Sure®, Nortrace®, NPactTM and Trisert®.
– Controlled release products: The only controlled release nitrogen fertilizer available for broad acre farming is ESN® SMART NITROGEN®, a urea granule encapsulated in a flexible polymer coating. Controlled release means ESN protects its nitrogen from loss and only releases its nitrogen in response soil temperature – the same trigger that spurs plant growth. Controlled release also means that ESN is designed to provide season-long feeding to plants.