Assessment of Non-Traditional Fertilizer Products, Inhibitors, and Enhancers in Mississippi.

Mississippi producers are continuing to grow corn for grain as an alternative to cotton under irrigated conditions.  As corn production increases, nitrogen (N) use also increases as corn requires about twice as much N as corn.  At the same time, nitrogen use efficiency (NUE) has become a buzz word and many different groups are offering products to enhance NUE.  Products vary from biological inhibitors that can reduce nitrification and ammonia volatilization to those that provide a slow release mechanism such as polymer coatings.  Studies have been established in cotton and corn to evaluate several products including ESN® (polymer coating), Agrotain® and Arborite® (contain NBPT), and NutriSphere-N® (for both liquid solutions and granular material).  Phosphorus (P) use in corn is greater than other crops and environmental concern have been voiced concerning P movement into streams.  Avail® has been promoted to increase P availability and uptake.  To evaluate these products under field conditions multiple field studies have been established for both cotton and corn.  These products are being compared to urea-ammonium nitrate solution (UAN, 32% N) and urea (46% N) at multiple N rates.  Avail®-treated phosphate fertilizer (0-46-0) is also being compared to untreated P at different rates.  Both Agrotain and Arborite contain NBPT which has been proven to reduce ammonia volatilization. However, research to date has not shown a significant advantage to the product if conditions do no favor volatilization losses.  Surface applications of urea, followed by rainfall, tend to decrease the potential for loss.  The ESN (Agrium Technologies) is a polymer-coated urea product that delays melting of the urea prill. Research in other parts of the country has shown significant yields responses to this product compared to uncoated material, especially under no-till conditions.  The NutriSphere-N® and Avail® (SFP, Leawood, KS) have not shown significant advantages for either corn or cotton.