The Effect of Enhanced-Efficiency Nitrogen Fertilizer Formulations on the Yield of Bermudagrass

D. Hancock and G. Harris

Enhanced-efficiency nitrogen fertilizer formulations may reduce potential environmental losses. The objectives of this research were to compare the yields of bermudagrass hay of Agrotain^® (ATU), Environmentally Smart Nitrogen^® (ESN), or Nutrisphere-N™ (NSN) treated urea to conventional applications of urea and ammonium nitrate (AN).  Plots (2.1 x 3.7 m) were delineated within a previously established stand of bermudagrass (cv. ‘Russell') at UGA Agricultural Experiment Station facilities near Calhoun and Eatonton, GA. Soil types were a silt loam and loam, respectively. The experiment was a randomized complete block design with four replicates. The treatment combinations included one rate of 336 kg actual N ha^-1 yr^-1 of ATU, ESN, NSN, or urea applied once or split among two applications during the season; urea or AN split equally across regrowth periods; and a 0 N control. Rainfall during the growing season (Mar-Sept) was severely drought stressed in 2007 and 2008. At both locations and years, there was a significant cutting date x treatment interaction. During the extremely dry first growth period, yields of the ESN treatments (512 kg DM ha^-1) were significantly less than ATU, NSN, urea, and AN treatments (1255 kg DM ha^-1), but not the check plots (570 kg DM ha^-1). However, N formulation did not have a consistently significant effect on yield in subsequent harvests.