Improving Nitrogen Best Management Practices with Enhanced Efficiency Fertilizer Technologies.

Good nitrogen (N) stewardship depends on the principles of using the right source at the right rate, at the right time, and in the right place.  Enhanced-efficiency N fertilizers (slow- and controlled-release and stabilized fertilizers) are defined as fertilizers that enhance plant recovery and reduce losses to the environment compared with an appropriate reference fertilizer.  Urease and nitrification inhibitors are well known and commonly recommended as components of some best management practices (BMPs).  Slow- and controlled-release N fertilizers have been shown to increase crop recovery and reduce leaching losses or gaseous losses to the atmosphere but have been less widely used in broad-acre agricultural crops.  Recent technological advances and higher N costs have increased the interest in these products.  Numerous reports on the benefits of enhanced-efficiency N fertilizers can be found in the literature, but proper use of these fertilizers, as with any fertilizer, is essential to get the full benefit of the technology.  Understanding the specific advantages and disadvantages of the variety of modes-of-action and technologies allows each product to be used most appropriately given a specific set of conditions.  The idea of BMPs suggests that each product is used in the situation and in the manner best for that product.  Therefore the use of enhanced-efficiency fertilizers within the BMP framework allows the grower to enhance other accepted BMPs or to replace an N management practice with a specific product or products that achieve the same result.  Ongoing research continues to define the benefits and proper use of enhanced-efficiency N fertilizers.