Evaluation of Enhanced Fertilizer Products for Sustainable Corn Production in the Mid South.

Nitrogen is often the most yield limiting agricultural input in irrigated, non-leguminous production systems.  Corn production systems across the Mid-South require high N application to sustain yields.  This has the potential to also lead to high N loss.  As a result, proper N management should focus not only on optimum production but also increasing N use efficiency (NUE).  The use of enhanced efficiency N fertilizers (EENF) has the potential to achieve both of these tasks.  While these products have been available for decades, limited research has directly compared the active chemicals for each of these EENF in corn production in the Mid-South, especially over varying N rates.  A study in 2013 and 2014 at two locations in Louisiana was conducted in a randomized complete block design with six replications. Factors included six different EENF applied in three different N rates.  Corn grain yield was significantly influenced by both N rate and EENF.  Additionally, a significant interactive effect was found between N rate and EENF indicating shifting optimum N rates when different fertilizer products were used.  However, across location, highest significant yields were achieved with pairing an urease and nitrification inhibitor (NBPT and DCD), which improved yields by nearly 3,000 kg ha^-1 over urea when applied at optimum rate.  As expected, a significant location by product as well as a treatment by year interactions existed.  This indicated that not only did the potential loss mechanisms vary between site locations but also varied between years at a single location.