THE IMPACT OF THE POLYMER COATING NUTRISPHERE™ IN INCREASING NITROGEN USE EFFICIENCY AND CORN YIELD

Currently, it is estimated that 50 to 60% of the N applied fertilizer is actually utilized by the crop with the remaining N lost through leaching or denitrification. A three year study was conducted at eight locations in North Carolina to examine the impact of Nutrisphere™ on corn yield, optimum N rate, maximum yield, tissue N concentration, plant biomass and N uptake. At six locations the study consisted of a split plot design where main plots were either 30% Urea Ammonium Nitrate (UAN) or 30% UAN plus Nutrisphere™ applied either at planting or layby with subplots consisting of five N rates that differed slightly across years. At two locations, two N solutions were applied at two rates to plots that received one of two starter fertilizer treatments. The overall trend indicated that Nutrisphere™ increased yield compared to the use of 30% UAN alone with a significant (p<0.10) yield increases of 0.74 Mg ha^-1 from combined results at Bertie08 and Pamlico08, 0.93 Mg ha^-1 from combined results at Guilford08 and Forsythe08 and 0.37 Mg ha^-1 from the treatment with at planting application of N at Beaufort09 and Pamlico09. While Nutrisphere™ only reduced optimum N rate in two trials, there was a consistent increase in maximum potential yield across trials. Plant analysis found that Nutrisphere™ increased biomass at one location, although it did not affect tissue N concentration and did not result in consistent increases in plant N uptake. The significant impacts of Nutrisphere™ on plant biomass and corn yield indicate that it affects the N movement to the root surface over a short period of time after application. More research is needed to determine how Nutrisphere™ impacts N movement in the soil, N transformations and N uptake to improve recommendations regarding its use and potential for increasing yield.