Effect of ESN Nitrogen Fertilizer On Bermudagrass Forage Production.

Forage producers are increasingly reliant on urea-based fertilizers because ammonium nitrate is less available in many areas. Reliance on urea puts the system at greater risk of nitrogen loss to ammonia volatilization. Environmentally Smart Nitrogen (ESN^®, Agrium Advanced Technologies, Brantford, Ontario) is a polymer-coated N fertilizer that controls the release of nitrogen through temperature-controlled diffusion. Studies have shown that ESN is effective in reducing volatilization losses and increasing N recovery. However, the release of nitrogen is too slow to be effective on early forage harvests. This study was designed to determine the response of different blends of ESN and untreated urea (0, 50, 75, and 100% ESN with 100, 50, 25, and 0% untreated urea, respectively) on ‘Russell’ bermudagrass (Cynodon dactylon) DM yield, N yield, N Recovery, nutritive quality, and NO₃ concentration compared to conventional treatments of AN and urea. The study was conducted in Eatonton and Calhoun, GA using a randomized complete block design with four replications. Nitrogen was applied at 336 kg N ha^-1 season^-1; in two equal applications for the treatments that were ESN blends and four equal applications for the conventional treatments over the season. The 50 and 75 percent ESN blends were: 10 and 6.1% higher in total DM yield, 14.4 and 19.5% more in total N removal, 2.2 and 5.4% higher in CP, and 0.4 and 0.8% higher in TDN, respectively, when compared to a conventional urea treatment, while still being comparable to AN. These ESN blends decreased the average nitrate concentration by 16.8% from the conventional AN treatment, but were 72.3% higher than the conventional urea. These results support the development of a recommendation of blending ESN at a rate of 50 and 75% with urea as a substitute for AN.